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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
Showing 1 - 200 of 265 Journals sorted alphabetically
AAS Open Research     Open Access   (Followers: 1)
Accountability in Research: Policies and Quality Assurance     Hybrid Journal   (Followers: 19)
Acta Materialia Transilvanica     Open Access  
Acta Nova     Open Access   (Followers: 2)
Acta Scientifica Malaysia     Open Access   (Followers: 1)
Acta Scientifica Naturalis     Open Access   (Followers: 4)
Adıyaman University Journal of Science     Open Access  
Advanced Science     Open Access   (Followers: 16)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 5)
Advances in Research     Open Access  
Advances in Science and Technology     Full-text available via subscription   (Followers: 18)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 7)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 1)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 3)
Alfarama Journal of Basic & Applied Sciences     Open Access   (Followers: 12)
American Academic & Scholarly Research Journal     Open Access   (Followers: 4)
American Journal of Applied Sciences     Open Access   (Followers: 22)
American Journal of Humanities and Social Sciences     Open Access   (Followers: 13)
ANALES de la Universidad Central del Ecuador     Open Access   (Followers: 1)
Anales del Instituto de la Patagonia     Open Access  
Applied Mathematics and Nonlinear Sciences     Open Access   (Followers: 2)
Apuntes de Ciencia & Sociedad     Open Access  
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 1)
Archives Internationales d'Histoire des Sciences     Partially Free   (Followers: 5)
Archives of Current Research International     Open Access  
ARO. The Scientific Journal of Koya University     Open Access  
ARPHA Conference Abstracts     Open Access   (Followers: 1)
ARPHA Proceedings     Open Access  
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access  
Asian Journal of Advanced Research and Reports     Open Access  
Asian Journal of Scientific Research     Open Access   (Followers: 2)
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 5)
Australian Field Ornithology     Full-text available via subscription   (Followers: 1)
Australian Journal of Social Issues     Hybrid Journal   (Followers: 6)
Avrasya Terim Dergisi     Open Access  
Bangladesh Journal of Scientific Research     Open Access  
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 1)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 11)
BIBECHANA     Open Access  
Bilge International Journal of Science and Technology Research     Open Access  
Bioethics Research Notes     Full-text available via subscription   (Followers: 15)
BJHS Themes     Open Access   (Followers: 2)
Black Sea Journal of Engineering and Science     Open Access  
Borneo Journal of Resource Science and Technology     Open Access  
Bulletin de la Société Royale des Sciences de Liège     Open Access  
Bulletin of the National Research Centre     Open Access  
Butlletí de la Institució Catalana d'Història Natural     Open Access  
Chain Reaction     Full-text available via subscription  
Ciencia Amazónica (Iquitos)     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia Ergo Sum     Open Access  
Ciência ET Praxis     Open Access  
Ciencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Citizen Science : Theory and Practice     Open Access   (Followers: 3)
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Communications in Applied Sciences     Open Access  
Comunicata Scientiae     Open Access  
ConCiencia     Open Access  
Conference Papers in Science     Open Access  
Configurations     Full-text available via subscription   (Followers: 11)
COSMOS     Hybrid Journal   (Followers: 1)
Crea Ciencia Revista Científica     Open Access  
Cuadernos de Investigación UNED     Open Access  
Current Issues in Criminal Justice     Hybrid Journal   (Followers: 14)
Current Research in Geoscience     Open Access   (Followers: 6)
Dalat University Journal of Science     Open Access  
Data     Open Access   (Followers: 4)
Data Curation Profiles Directory     Open Access   (Followers: 9)
Dhaka University Journal of Science     Open Access  
Diálogos Interdisciplinares     Open Access  
Digithum     Open Access   (Followers: 2)
Discover Sustainability     Open Access   (Followers: 5)
Einstein (São Paulo)     Open Access  
Ekaia : EHUko Zientzia eta Teknologia aldizkaria     Open Access  
Elkawnie : Journal of Islamic Science and Technology     Open Access  
Emergent Scientist     Open Access  
Enhancing Learning in the Social Sciences     Open Access   (Followers: 7)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Entramado     Open Access  
Entre Ciencia e Ingeniería     Open Access  
Epiphany     Open Access   (Followers: 1)
Estação Científica (UNIFAP)     Open Access  
Ethiopian Journal of Education and Sciences     Open Access   (Followers: 5)
Ethiopian Journal of Science and Technology     Open Access  
Ethiopian Journal of Sciences and Sustainable Development     Open Access  
European Online Journal of Natural and Social Sciences     Open Access   (Followers: 4)
European Scientific Journal     Open Access   (Followers: 7)
Evidência - Ciência e Biotecnologia - Interdisciplinar     Open Access  
Exchanges : the Warwick Research Journal     Open Access   (Followers: 1)
Experimental Results     Open Access   (Followers: 2)
Facets     Open Access  
Fides et Ratio : Revista de Difusión Cultural y Científica     Open Access  
Fırat University Turkish Journal of Science & Technology     Open Access  
Fontanus     Open Access   (Followers: 1)
Forensic Science Policy & Management: An International Journal     Hybrid Journal   (Followers: 247)
Frontiers for Young Minds     Open Access  
Frontiers in Climate     Open Access   (Followers: 5)
Frontiers in Science     Open Access   (Followers: 1)
Fundamental Research     Open Access  
Futures & Foresight Science     Hybrid Journal   (Followers: 1)
Gaudium Sciendi     Open Access  
Gazi University Journal of Science     Open Access  
Ghana Studies     Full-text available via subscription   (Followers: 15)
Global Journal of Pure and Applied Sciences     Full-text available via subscription  
Global Journal of Science Frontier Research     Open Access   (Followers: 1)
Globe, The     Full-text available via subscription   (Followers: 4)
HardwareX     Open Access  
Heidelberger Jahrbücher Online     Open Access  
Heliyon     Open Access   (Followers: 1)
Himalayan Journal of Science and Technology     Open Access  
History of Science and Technology     Open Access   (Followers: 6)
Hoosier Science Teacher     Open Access  
Impact     Open Access   (Followers: 1)
Indian Journal of History of Science     Hybrid Journal   (Followers: 3)
Indonesian Journal of Fundamental Sciences     Open Access  
Indonesian Journal of Science and Mathematics Education     Open Access   (Followers: 2)
Indonesian Journal of Science and Technology     Open Access  
Ingenieria y Ciencia     Open Access   (Followers: 1)
Innovare : Revista de ciencia y tecnología     Open Access  
Instruments     Open Access  
Integrated Research Advances     Open Access  
Interciencia     Open Access  
Interface Focus     Full-text available via subscription  
International Annals of Science     Open Access  
International Archives of Science and Technology     Open Access  
International Journal of Academic Research in Business, Arts & Science     Open Access  
International Journal of Advanced Multidisciplinary Research and Review     Open Access  
International Journal of Applied Science     Open Access  
International Journal of Basic and Applied Sciences     Open Access   (Followers: 1)
International Journal of Computational and Experimental Science and Engineering (IJCESEN)     Open Access  
International Journal of Culture and Modernity     Open Access   (Followers: 5)
International Journal of Engineering, Science and Technology     Open Access  
International Journal of Engineering, Technology and Natural Sciences     Open Access  
International Journal of Innovation and Applied Studies     Open Access   (Followers: 4)
International Journal of Innovative Research and Scientific Studies     Open Access   (Followers: 1)
International Journal of Network Science     Hybrid Journal   (Followers: 3)
International Journal of Recent Contributions from Engineering, Science & IT     Open Access  
International Journal of Research in Science     Open Access   (Followers: 1)
International Journal of Social Sciences and Management     Open Access   (Followers: 2)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 10)
International Letters of Social and Humanistic Sciences     Open Access  
International Science and Technology Journal of Namibia     Open Access   (Followers: 2)
International Scientific and Vocational Studies Journal     Open Access  
InterSciencePlace     Open Access  
Investiga : TEC     Open Access  
Investigación Joven     Open Access  
Investigacion y Ciencia     Open Access   (Followers: 1)
Iranian Journal of Science and Technology, Transactions A : Science     Hybrid Journal  
iScience     Open Access   (Followers: 2)
Issues in Science & Technology     Free   (Followers: 8)
Ithaca : Viaggio nella Scienza     Open Access  
J : Multidisciplinary Scientific Journal     Open Access  
Jaunujų mokslininkų darbai     Open Access   (Followers: 3)
Journal de la Recherche Scientifique de l'Universite de Lome     Full-text available via subscription  
Journal of Chromatography & Separation Techniques     Open Access   (Followers: 9)
Journal of Advanced Research     Open Access   (Followers: 2)
Journal of Al-Qadisiyah for Pure Science     Open Access  
Journal of Alasmarya University     Open Access   (Followers: 3)
Journal of Analytical Science & Technology     Open Access   (Followers: 5)
Journal of Applied Science and Technology     Full-text available via subscription   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)
Journal of Big History     Open Access   (Followers: 4)
Journal of Composites Science     Open Access   (Followers: 4)
Journal of Diversity Management     Open Access   (Followers: 4)
Journal of Indian Council of Philosophical Research     Hybrid Journal  
Journal of Institute of Science and Technology     Open Access  
Journal of Integrated Science and Technology     Open Access  
Journal of King Saud University - Science     Open Access  
Journal of Mathematical and Fundamental Sciences     Open Access  
Journal of Natural Sciences Research     Open Access   (Followers: 2)
Journal of Negative and No Positive Results     Open Access  
Journal of Responsible Technology     Open Access  
Journal of Science (JSc)     Open Access  
Journal of Science and Engineering     Open Access   (Followers: 1)
Journal of Science and Technology     Open Access   (Followers: 2)
Journal of Science and Technology     Open Access   (Followers: 1)
Journal of Science and Technology (Ghana)     Open Access   (Followers: 3)
Journal of Science and Technology Policy Management     Hybrid Journal   (Followers: 1)
Journal of Science Foundation     Open Access   (Followers: 1)
Journal of Science of the University of Kelaniya Sri Lanka     Open Access  
Journal of Scientific Research     Open Access   (Followers: 1)
Journal of Scientific Research and Reports     Open Access   (Followers: 1)
Journal of Scientometric Research     Open Access   (Followers: 22)
Journal of Shanghai Jiaotong University (Science)     Hybrid Journal  
Journal of Social Science Research     Open Access   (Followers: 2)
Journal of Taibah University for Science     Open Access  
Journal of the Asiatic Society of Bangladesh, Science     Open Access  
Journal of the Ghana Science Association     Full-text available via subscription   (Followers: 3)
Journal of the History of Ideas     Full-text available via subscription   (Followers: 168)
Journal of the Indian Institute of Science     Hybrid Journal   (Followers: 4)
Journal of the National Science Foundation of Sri Lanka     Open Access  
Journal of the Royal Society of New Zealand     Hybrid Journal   (Followers: 49)
Journal of the South Carolina Academy of Science     Open Access  
Journal of Unsolved Questions     Open Access  
Jurnal Ilmiah Ilmu Terapan Universitas Jambi : JIITUJ     Open Access  
Jurnal Matematika, Sains, Dan Teknologi     Open Access  

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ARPHA Conference Abstracts
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ISSN (Online) 2603-3925
Published by Pensoft Homepage  [58 journals]
  • Pathogen survival in groundwater: Influence of redox and organic matter

    • Abstract: ARPHA Conference s 6: e108697
      DOI : 10.3897/aca.6.e108697
      Authors : Louise Weaver, Erin McGill, Panan Sitthirit, Judith Webber, Phil Abraham, Murray Close : Microbial pathogen survival within the environment can be variable and can depend on many criteria, including environmental conditions e.g. oxygen concentration, temperature, pH, sunlight, etc. (e.g., Horswell et al. (2010)). Groundwater has been shown to enable the prolonged survival of pathogenic organisms due to the absence of sunlight and relatively stable temperatures (Cook and Bolster 2007). In other studies, however, survival has been lower in groundwater when compared with a sterile environment (e.g. sterilised groundwater or artificial groundwater) due to the presence of competing organisms and adverse conditions of pH and redox.To elucidate these discrepancies two experiments were designed: The first, hypothesised that, due to Campylobacters' low tolerance to high oxygen levels, survival in oxic (dissolved oxygen (DO) levels over 5 mg per L) would be less than in anoxic groundwater (DO levels below 2 mg per L). The second hypothesised that the survival of the pathogen Salmonella typhimurium, in groundwater, will be enhanced by organic carbon.METHODSCampylobacter experiment:Campylobacter jejuni isolated from the Havelock North drinking water source was used (designated HN16) (Gilpin et al. 2020). To compare the survival of the outbreak strain with type strain Campylobacter, NCTC 11351 was used.Salmonella experiment:For this experiment, environmental isolates were used rather than laboratory strains. Salmonella, isolated from a stream in Wellington, New Zealand, was identified as Salmonella enterica serovar Typhimurium. The Escherichia coli used was a phylogroup A, isolated from stream sediment in Whangarei Falls, New Zealand.Mesocosm experiments were established containing groundwater (oxic and anoxic for Campylobacter experiment and ultrafiltered, groundwater, groundwater amended with 1% or 10% dissolved organic carbon (DOC). pH, dissolved oxygen (DO), and temperature were monitored over the experimental period. The temperature was maintained at 12-14°C during both experiments.Samples (5 mL) of the groundwater from each jar were taken aseptically at set time points over the experimental period. Samples were then serially diluted in sterile peptone water to give a dilution series from 10-1 to 10-4. Samples were analysed by plating onto selective media.RESULTSCampylobacter experiment:The results presented demonstrated differences in the survival of the two Campylobacter strains tested and differences in survival of Campylobacter HN16 depending on groundwater type. Fig. 1 shows the average concentration of Campylobacter strains in groundwater types over time. The results presented are average of three replicates. Over the whole experimental period survival of Campylobacter HN16 was greatest in anoxic groundwater, and only a 1 log reduction was observed (Fig. 1), equating to a 79.6% survival after 16 days. The die-off rate of Campylobacter HN16 in anoxic groundwater was calculated to be 0.0873 days and T90 6.85 days.Salmonella experiment:Die-of rates for Salmonella were similar over the course of the experiment when no or low levels of DOC were present (Fig. 2a). At high levels of DOC, however, Salmonella showed similar survival to the control. After 84 days only a 1 Log decrease was observed. In comparison, E. coli died off at a faster rate than Salmonella in all mesocosms (Fig. 2). It is interesting to note that in the high DOC mesocosms after day 56 counts of E. coli remained at 103 per mL until the end of the experiment.Conclusions and significanceBoth experiments demonstrated the survival of pathogenic microorganisms in varying groundwater conditions. The variation in the outbreak strain Campylobacter compared to the type strain indicated variation within species that may lead to enhanced survival in the environment. The Salmonella experiment indicated the presence of additional organic carbon can enhance the survival of pathogens in groundwater. In addition, the variation between the microbial indicator E. coli and Salmonella provides evidence of differences in the survival of microbes in the environment and indicates caution is needed when considering the survival of pathogens in groundwater if reliance is made on microbial indicator organisms. HTML XML PDF
      PubDate: Mon, 23 Oct 2023 15:31:00 +030
       
  • Groundwater Diversity across New Zealand: From micro to macro-scale

    • Abstract: ARPHA Conference s 6: e108433
      DOI : 10.3897/aca.6.e108433
      Authors : Louise Weaver, Judith Webber, Phil Abraham, Annette Bolton, Panan Sitthirit, Murray Close : Groundwater is home to a diverse range of organisms, both small and large, which form a complex ecosystem that helps to purify the water and keep it flowing smoothly. However, much of the processes that occur in this ecosystem are still a mystery and there are many important services that we have yet to fully understand. Our goal is to create a groundwater health index that can be used to monitor the health of groundwater, similar to the macroinvertebrate community index used for surface water systems. We are investigating both the macroinvertebrates and microbial diversity in our research. To gather data, we are collecting groundwater environmental (e)DNA samples and biofilm samples using in-situ biofilm bags from various sites in New Zealand across multiple seasons. We then analyze the water chemistry and sequence data for bacteria, archaea, eukaryotes, and fungi to determine the status of the groundwater source. Our findings show that there is a complex diversity present in both the groundwater itself (e.g., Fig. 1) and the attached microbial biofilm. We have also discovered variations between the attached and groundwater across all sites studied, with significant differences in the Shannon richness indicator in Canterbury. Additionally, we have observed differences in microbial populations depending on the lithology and water chemistry present. Our research aims to identify key species, both micro and macro, that can potentially act as a tool for predicting the health of groundwater. Furthermore, understanding the biological processes occurring in our groundwater may lead to the discovery of beneficial organisms capable of remediation. HTML XML PDF
      PubDate: Mon, 23 Oct 2023 15:30:00 +030
       
  • Characterizing biofilms and their associated biosignatures in an Arctic
           hypersaline cold spring Mars analog

    • Abstract: ARPHA Conference s 6: e111363
      DOI : 10.3897/aca.6.e111363
      Authors : Olivia Blenner-Hassett, Ianina Altshuler, Elisse Magnuson, Lyle Whyte : The last surface-level aqueous environments on Mars were likely sulfurous brines that formed as the climate cooled and large bodies of water receded during the transition from the wet Noachian to the dry Hesperian (4.1 – 3.0 Gya). To understand the diversity of microorganisms that could have inhabited such environments and their associated biosignatures, we turn to analogous environments on Earth. Here we investigated biofilm communities and their associated biosignatures at Gypsum Hill, (GH), a perennial cold spring system located at nearly 80°N on Axel Heiberg Island in the Canadian high Arctic. The biofilms develop during the summer months alongside the oligotrophic and sulphur rich GH brines and spread out along the flood plains formed by meltwater and spring run-off. Our objective was to link the microbial community structure of the biofilms to geochemical changes across the GH site as an analog to the micro-niches that could have formed during the recession of an ancient Martian Ocean. We collected 14 morphologically distinct biofilms over two field season and found that minor variations in chemistry between proximal sites impacted community structure. 16S amplicon sequencing revealed that biofilms closest to outflow channels were dominated by sulfur oxidizing bacteria, suggesting that primary production may be driven by chemolithoautotrophy. The community structure shifted towards more heterotrophic and phototrophic populations the further the biofilms appeared from a spring source. Microbial eukaryotes at the GH site were investigated for the first time through 18S sequencing with diatoms and photoautotrophic algae dominating all biofilms. Lastly, we linked the biofilm communities to potential biosignatures by examining lipid profiles to help guide the search and identification of potential remnants of hypothetical ancient Martian life.  HTML XML PDF
      PubDate: Wed, 18 Oct 2023 22:41:54 +030
       
  • Improving conventional household greensand treatment for efficient Mn(II)
           removal from drinking water

    • Abstract: ARPHA Conference s 6: e111924
      DOI : 10.3897/aca.6.e111924
      Authors : Binrui Li, Debra Hausladen : Geogenic contaminants pose a global threat to ensuring access to safe drinking water. Manganese (Mn) is a naturally-occurring redox-active element which in its reduced form, Mn(II), is a widespread groundwater contaminant. Prolonged consumption of water containing high levels of Mn has been linked to adverse effects on memory, attention, motor skills, and nervous system function, particularly in vulnerable groups including pregnant individuals and young children. In addition, Mn can lead to aesthetic issues such as altered taste, clogging, and damage to plumbing systems. While Mn has historically been regulated as an aesthetic concern, a mounting body of evidence linking health issues to Mn exposure through drinking water has heightened the challenges of using groundwater to meet drinking water needs. Recently, Health Canada established a health guideline which set a maximum acceptable concentration for total Mn in drinking water of 120 μg/L. Greensand (GS) filters are commonly used in conventional drinking water treatment systems for Mn(II) removal due to their cost-effectiveness and high exchange capacity. However, under certain conditions conventional GS systems may have a low Mn(II) removal efficiency (Galangashi et al. 2021) and encounter challenges related to Mn leaching (Outram et al. 2018), resulting in failure to meet health-related standards. Furthermore, GS filters typically undergo regeneration using potassium permanganate (KMnO4), a mild oxidant that results in the release of additional Mn waste byproducts during the regeneration of the filter. Recent research suggests that Mn-containing materials can effectively activate peroxymonosulfate (PMS) and produce reactive oxygen species (ROS) that facilitate contaminant degradation. This study aims to investigate whether PMS may be used to improve greensand treatment systems and enhance Mn(II) removal from drinking water. Batch experiments were performed to test the Mn(II) removal efficiency across a range of PMS concentrations (0-500 μM) and GS mass (0.1-3 g). Aqueous Mn concentrations were measured over time using inductively coupled plasma optical emission spectrometry (ICP-OES). Solid-phase reaction products were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The mechanisms of Mn oxidation were identified by quenching experiments and electron paramagnetic resonance (EPR) spectroscopy. The activation of PMS by greensand significantly increased the removal efficiency of Mn(II) compared to the conventional method (e.g., 96.83(±3.77)% at PMS = 500 µM vs. 5.77(±11.1)% at PMS = 0 µM). Our results attribute the mechanism underlying increased Mn removal in our improved treatment method to advanced oxidation processes that involve free radicals (e.g., hydroxyl radical (·OH) and sulfate radical (SO4·-)) and non-free radical pathways, with Mn oxides as the main oxidation products. This study provides a new treatment method for more efficient Mn(II) removal while simultaneously reducing Mn wastes produced during the regeneration cycle which allows for a more sustainable and holistic management of invaluable groundwater resources. HTML XML PDF
      PubDate: Wed, 18 Oct 2023 20:21:06 +030
       
  • Relationship Between Sulfidated Nano Zero Valent Iron and a Reductive
           Dechlorinating Microbial Culture - Synergistic or Antagonistic' 

    • Abstract: ARPHA Conference s 6: e111354
      DOI : 10.3897/aca.6.e111354
      Authors : Chao-Lung Yang, Jingzhi Liang, Hardiljeet Boparai, Jiayu Yao, Line Lomheim, Elizabeth Edwards, Brent Sleep : Sulfidated nano zerovalent iron (S-nZVI) has garnered significant attention from researchers due to its potential for effective in-situ remediation applications. Compared to bare nZVI, sulfidation process enhances its reactivity towards chlorinated volatile organic compounds (cVOCs) and improves its longevity (Nunez Garcia et al. 2021). Stabilizing the particles with a polymer, like carboxymethyl cellulose (CMC), can further improve the performance of S-nZVI by imparting higher stability, less toxicity towards microbial cells, and a potential biostimulatory effect, making CMC-S-nZVI a promising in-situ remediation technology (Nunez Garcia et al. 2021).Recently, CMC-S-nZVI has also been applied for field-scale remediation (Nunez Garcia et al. 2020;Brumovský et al. 2021). The contaminated sites usually have multiple pollutants and not all can be degraded by CMC-S-nZVI, thus, leaving some recalcitrant cVOCs untreated (Zhang et al. 2021). Biodegradation of cVOCs by dechlorinating microbial cultures may generate highly toxic intermediates like vinyl chloride (Kocur et al. 2016). However, coupling the two treatments may be able to compensate for each other’s drawbacks, resulting in higher efficiency, longer effectiveness, non-accumulation of intermediates, and degradation of a wider range of target contaminants. However, interacting effects of CMC-S-nZVI on dechlorinating microbial cultures have not been studied yet.This research investigates the potential of combining CMC-S-nZVI and a reductive dechlorinating microbial culture (KB-1) to degrade trichloroethylene (TCE) and 1,2-dichloroethane (1,2-DCA). CMC-S-nZVI was synthesized by a two-step method: (1) CMC-nZVI was first synthesized by reducing ferrous sulfate-CMC solution with dropwise addition of sodium borohydride solution with continuous mixing and (2) then sodium dithionite solution was added as a sulfidation agent to the freshly-synthesized CMC-nZVI (Nunez Garcia et al. 2020). Effects of different sulfur-iron ratios (S/Fe), iron, and CMC concentrations on TCE degradation were studied to obtain an effective CMC-S-nZVI formulation. Results showed a successful TCE removal by the CMC-S-nZVI but 1,2-DCA was not degraded. TCE degradation by CMC-S-nZVI fitted the first-order kinetic model, with the highest degradation rate constant (0.35 h-1) achieved at S/Fe = 0.1 with iron and CMC concentrations of 1 gL-1 and 0.4 wt%, respectively. This CMC-S-nZVI formulation was further tested to examine its interaction with KB-1 in terms of cVOCs dechlorination and microbial population responses. A four-day aged CMC-S-nZVI was also tested to study the effect of aging. Degradation pathways for TCE and 1,2-DCA were proposed, based on the formation of degradation products.For the coupled treatment, an increase in microbial abundance was observed by quantifying DNA concentrations. This demonstrated a synergistic relationship between CMC-S-nZVI and KB-1. Unlike the CMC-S-nZVI only treatment, microcosms containing both CMC-S-nZVI and KB-1 were found to successfully degrade the 1,2-DCA. The coupled treatment degraded TCE and 1,2-DCA at faster rates and generated lesser amounts of vinyl chloride than the KB-1 only treatment, confirming the biostimulatory effect of CMC-S-nZVI. In the KB-1 only treatment with CMC as the sole carbon and energy source, TCE and 1,2-DCA were successfully dechlorinated. Transmission electron microscopy illustrated that CMC-S-nZVI particles were attached to the microbes but did not penetrate the bacterial cells. In summary, synergistic abiotic-biotic dechlorination of TCE and 1,2-DCA was achieved by the combined treatment of CMC-S-nZVI and KB-1, suggesting that multi-contaminant sites can benefit from this approach. Additionally, the four-day aged CMC-S-nZVI performed similar to the freshly-synthesized one, demonstrating that the field-scale remediation can have a more feasible time scale for the preparation and application of these amendments. HTML XML PDF
      PubDate: Wed, 18 Oct 2023 19:24:32 +030
       
  • Glacial secrets uncovered: Revealing the modes of survival of
           

    • Abstract: ARPHA Conference s 6: e108883
      DOI : 10.3897/aca.6.e108883
      Authors : Brady O'Connor, Lyle Whyte : Glaciers, once dismissed as inhospitable environments, have been overlooked in scientific investigations. Previous studies have primarily focused on the supraglacial (cryoconite holes, snow, and meltwater) and subglacial (bedrock and soils, among others) environments, neglecting the englacial (inside ice) realm. Despite evidence demonstrating the survival of cells in glacial/sea ice (Christner 2000, Junge et al. 2002, Miteva et al. 2004, Miteva and Brenchley 2005) and theoretical predictions and indirect evidence hinting at active microbial communities within glacial ice (Krembs et al. 2002, Junge et al. 2004, Price and Sowers 2004, Tung et al. 2005, Tung et al. 2006, Rohde et al. 2008), the englacial environment has remained largely unexplored.Recognizing that englacial ice hosts potentially active microbial communities carries significant implications for the future of these habitats in the face of escalating global warming and glacial retreat. As glaciers rapidly melt due to the effects of global warming, the liberation of these microbial communities will undoubtedly exert profound effects on local ecosystems and biogeochemical cycles, presenting an array of unknown consequences. Furthermore, considering the ability of microbial communities to persist in such extreme conditions on Earth, they become intriguing subjects for the search for life on celestial bodies such as Mars, Europa, Enceladus, and Titan, all of which house vast ice deposits.However, several fundamental questions persist. The extent of metabolic activity in glacial ice remains uncertain, as does the identification of microorganisms capable of sustaining metabolic processes. Most importantly, understanding the survival strategies employed by these organisms in such an extreme environment remains unknown.To answer these questions, we present metagenomes and what we believe to be the first metatranscriptomes ever analyzed from glacial ice. We have developed a method which allows us to melt ice cores without altering the mRNA profile of the microorganisms within, allowing us to directly determine how microorganisms are able to survive in such a hostile environment. One-to-two-meter cores were taken from the surface of White Glacier, Axel Heiberg Island and from the Devon Island ice cap, both in the Canadian High Arctic. A depth of 70 – 90 cm and 131 – 151 cm was chosen for analysis from White Glacier and Devon Island respectively. In the lab, to remove surface contamination from the cores, the outer 0.5 cm of the cores was removed, and the inner cores were sprayed with 70% ethanol. The decontaminated core subsections were melted at 4°C directly into DNA/RNA Shield (1:1 ratio) which preserved the microbial communities on contact, preventing changes to the metagenome or metatranscriptome during melt. Melted samples were filtered and nucleic acids extracted before DNA and RNA sequenced on an Illumina NovaSeq 6000 sequencer. Sequencing yield from Devon ice cap was low, resulting in few metagenomic and metatranscriptomic sequences however White Glacier produced a metagenome of 46 million reads and a metatranscriptome of 56 million reads. These data revealed that White Glacier is dominated by Cyanobacteria and Actinobacteria and the Devon ice cap is dominated by Proteobacteria. Furthermore, metatranscriptomic analysis of microorganisms from White Glacier revealed a metabolically active microbial community reliant on oxygenic photosynthesis, and carbon fixation via the Calvin and 3-hydroxypropionate Cycles. Transcripts related to aerobic respiration, aerobic carbon monoxide oxidation, sulfur oxidation, nitrite oxidation, nitric and nitrous oxide reduction and anoxygenic photosynthesis were also present. Cold adapted microorganisms possess many mechanisms to deal with low temperatures and the microbial community of White Glacier is no different. Cold response genes were highly expressed, principally membrane and peptidoglycan modifying proteins which increase membrane and cell wall fluidity at low temperatures, translation and transcription factors which increase the efficiency of protein synthesis at low temperatures, and cold shock proteins which stabilize RNA at low temperatures.Two high and five medium quality metagenome assembled genomes (MAGs) were also recovered from the White Glacier ice core, including a 99.86% complete Coleofasciculaceae Cyanobacterial genome with transcripts mapping to its genome related to aerobic respiration, oxygenic photosynthesis, carbon fixation (Calvin cycle) and nitrous oxide reduction. Transcripts related to cold response included those from categories such as cold shock proteins, DNA repair, membrane and peptidoglycan alteration, osmotic stress, and transcription and translation factors. Transcripts involved in DNA replication even mapped to the genome of this organism indicating it was capable of cell division in the ice.Overall, our research suggests that englacial ice can support an active microbial community where Cyanobacteria act as primary producers, generating energy from photosynthesis and fixing carbon from trapped atmospheric CO2. Carbon monoxide is also used as an energy source. As expected, cold adaptation genes are widespread and highly expressed indicating a community highly adapted to life in glacial environments and which may even be capable of growth. This research is significant because it presents the first metatranscriptomic profile of microorganisms trapped within glaciers, challenging preconceived notions about the habitability of ice. These results carry profound implications for the field of astrobiology and the quest to uncover signs of life within Martian glaciers o...
      PubDate: Wed, 18 Oct 2023 19:00:00 +030
       
  • The Crucial Relationship: Reinforcing the Role of Microbial Mats in Early
           Animal Life

    • Abstract: ARPHA Conference s 6: e111320
      DOI : 10.3897/aca.6.e111320
      Authors : Baptiste Coutret, Kurt Konhauser, Marc Laflamme, Murray Gingras : The stem-group eumetazoans, also known as basal animals, have been present on Earth since the Neoproterozoic era, as evidenced by the fossil record of the Ediacaran Period (Xiao and Laflamme 2009, Butterfield 2011, Darroch et al. 2018). Previously, it was thought that Ediacaran microbial mats (also called biomats) were a key factor for early animals, providing food resources and stimulating motility and burrowing strategies into the sediment (Seilacher 1999, Meyer et al. 2014, Buatois et al. 2014, Tarhan et al. 2017, Scott et al. 2020, Coutret and Néraudeau 2022). Other research has suggested that animals living within modern microbial mats could have used the latter as a source of O2, and thus they were not reliant upon bottom water oxygenation (e.g., Gingras et al. (2007), Gingras et al. (2011)). This observation leads to the hypothesis that free dissolved O2 within the microbial mats could have facilitated the evolution of primitive animals in the Ediacaran oceans (Gingras et al. 2011). This is significant because the low concentration of dissolved O2 is often considered a significant environmental obstacle for complex animals (Lyons et al. 2014, Knoll and Sperling 2014, Boag 2018). On the other hand, it is frequently observed that microbial mats have the ability to trap and bind sediment, and in some cases, they can even induce mineral precipitation. Following the process of lithification, the once "soft" biofilms are transformed into biolaminated organosedimentary structures known as stromatolites (Konhauser 2009). Critically, the earliest biomineralized metazoans (e.g., Cloudina - Namacalathus) are found within biostromal carbonate reefs supported by microbialites (Hofmann and Mountjoy 2001, Penny et al. 2014; also illustrated in Fig. 1A, B: Byng Formation in the Mont Robson area (BC, Canada)). Characterized as sessile and gregarious, epibenthic filter feeders, we propose that the earliest biomineralized metazoans derived advantages from stromatolitic reefs by becoming encrusted or attached to them in shallow water environments (Fig. 1A, B: white arrows). Stromatolites are regarded as fossilized relics of microbial communities and occupied various subaqueous and shallow water environments, such as tidal flats, potentially dating back as far as 3.4 billion years ago (Gehling 1999, Walter et al. 1980). However, there is a lack of study regarding the role of stromatolites in the life of early animals. Recent field investgations, led by our group, in Cooking Lake (Canada) have demonstrated that animals are burrowing into sediments and actively exploiting the microbial mats not only for food resources, but also for oxygen (Fig. 1C-E). Other extensive Ediacaran microbialites (e.g., Fig. 1F) have been discovered in recent field studies in the Byng Formation from the Jasper area (AB, Canada). Interestingly, the earliest biomineralized metazoans were described from a similar depositional environment (Fig. 1A, B: Byng Formation in the Mont Robson area (BC, Canada). Consequently, we aim to reinterpret the role of microbial mats in early animal life by examining: 1) trace fossils associated with fossilized microbial textures; 2) modern 'soft' biofilms that produce O2 with fresh bioturbations; and 3) mineralized bioconstructions (stromatolitic biostromes and thrombolitic reef-mound carbonates from the Ediacaran period). These reinterpretations will enable us to speculate about the significance of microbial communities, such as oxygenic photosynthetic cyanobacteria, on early animal evolution. HTML XML PDF
      PubDate: Wed, 18 Oct 2023 18:51:33 +030
       
  • Non-syntrophic Methanogenic Hydrocarbon Degradation by an Archaeal Species

    • Abstract: ARPHA Conference s 6: e111614
      DOI : 10.3897/aca.6.e111614
      Authors : Zhuo Zhou, Cuijing Zhang, Pengfei Liu, Lin Fu, Rafael Laso-Pérez, Lu Yang, Liping Bai, Jiang Li, Min Yang, Junzhang Lin, Weidong Wang, Gunter Wegener, Meng Li, Lei Cheng : Methanogenic hydrocarbon biodegradation alters the composition of many subsurface oil reservoirs (Jones et al. 2007). This process reduced the crude oil quality by removing alkanes and thus increasing the oil viscosity. The process has been described for syntrophic associations of hydrocarbon-degrading bacteria and methanogenic archaea (Zengler et al. 1999, Dolfing et al. 2007). However, recent culture-independent studies suggest that the archaeon ‘Candidatus Methanoliparum’ may combine alkane degradation and methanogenesis (Laso-Pérez et al. 2019, Borrel et al. 2019). Here we cultured Ca. Methanoliparum from a subsurface oil reservoir. To study this culture, situ hybridization, metagenomics and metatranscriptomics were combined with stable isotope probing and metabolite analyses for describing its functioning and assessing its potential role in reservoir chemistry.Incubated an anoxic oily sludge of the Shengli oilfield with sulfate-free medium, we established a methanogenic culture. This culture consumed various different long-chain alkanes, but also alkyl-benzenes and alkyl-cycloalkanes, and produced methane and CO2 as products (Fig. 1a-b). Our analyses revealed that our culture is dominated by a single archaeon, Ca. Methanoliparia (green).To study the specific turnover of n-alkanes, the cultures were supplemented with 1,2-13C-labelled or unlabelled n-hexadecane (Fig. 2). Within 100 days of incubation, both compounds were quantitatively converted into methane and carbon dioxide. In the 13C-labelling experiment, around 0.46 mmol of 13CH4 and around 0.15 mmol of 13CO2 were produced, which was equal to 85% to 92% of the stoichiometric conversion of the supplemented labelled hexadecane according to 4C16H34 + 30H2O -- 49CH4 + 15CO2 (Fig. 2a-d).We examined the functioning of Ca. Methanoliparum in the hexadecane-degrading culture using amplicon sequencing, metagenomics and metatranscriptomics. In the archaeal domain, the relative abundance of Ca. Methanoliparum in the hexadecane-degrading cultures comprised up to 75% of the total abundance according to analysis of archaeal 16S rRNA genes. Furthermore, Ca. Methanoliparum accounted for approximately 34–40% of the total microbial community as determined by metagenomic read recruitment estimation (Fig. 2e-f).We analysed the gene expression patterns of Ca. Methanoliparum during methanogenic hexadecane degradation (Fig. 3). The genes encoding the methanogenic hexadecane degradation pathway ranked among the top 10% to 25% of all Ca. M. thermophilum transcribed genes. Moreover, genes of Ca. M. thermophilum encoding ACR and MCR ranked among the top 2% of all transcribed genes within the whole community (Fig. 3b). The MAGs of Ca. M. thermophilum also showed the highest transcription among all described MAGs (Fig. 3c). These analyses indicate that Ca. M. thermophilum performs both the degradation of hexadecane and the formation of methane.We searched the cell extracts of the hexadecane-degrading cultures for hexadecyl-CoM formation using Q-Exactive Plus Orbitrap masss pectrometry. The unlabelled hexadecane culture contained a prominent mass peak of m/z = 365.21868 that matches the mass produced by synthesized authentic standard of hexadecyl-CoM. Fragmentation of both peaks yielded hexadecyl-thiol (m/z = 257.23080, C16H33S−), ethenesulfonate (m/z = 106.98074, C2H3SO3−) and bisulfite (m/z = 80.96510, HSO3−). Moreover, cultures supplied with 1,2-13C-hexadecane produced a peak at m/z = 367.22524 for 1,2-13C-hexadecyl-CoM and the fragment 259.23721 for 1,2-13C-hexadecyl-thiol, with a mass shift of 2 units compared with the unlabelled group. These analyses confirmed the activation of n-hexadecane as hexadecyl-CoM (Fig. 4).Here we demonstrate the activation of different hydrocarbon classes by ACRs of Ca. Methanoliparum, expanding the substrate range of this enzyme to an unforeseen number of compounds. Ca. Methanoliparum couples the degradation of long-chain alkanes and alkyl-substituted hydrocarbons to methane formation, proposed as alkylotrophy. Its metabolic pathways represent an additional mode of methanogenesis, adding to CO2 reduction, methylotrophy, methyl reduction, acetate fermentation and the recently reported methoxydotrophy. Ca. Methanoliparum grows in a wide temperature range, at least between 35 and 55 °C, covering the temperature range of most biodegraded oil reservoirs. Indeed, sequences of Ca. Methanoliparum are present in various anoxic hydrocarbon-rich environments worldwide. Thus, the demonstration of the unique features of Ca. Methanoliparum in hydrocarbon conversion may fundamentally change our view of crude oil transformation and biogeochemical processes in subsurface oil reservoirs. Future studies with Ca. Methanoliparia cultures will resolve the biochemical mechanisms of methanogenic hydrocarbon degradation in archaea, and will be helpful for the application of microbial-enhanced energyrecovery from depleted oil reservoirs. HTML XML PDF
      PubDate: Wed, 18 Oct 2023 17:58:17 +030
       
  • Chemo-organo-autotrophic degradation of aromatic hydrocarbons indicates a
           new type of bacterial metabolism

    • Abstract: ARPHA Conference s 6: e111950
      DOI : 10.3897/aca.6.e111950
      Authors : Rainer U. Meckenstock, Isabelle Heker, Christian Seitz, Lisa Voskuhl, Wolfgang Eisenreich : The sulfate-reducing culture N47 can grow with naphthalene and has a complete tricarboxylic acid cycle (TCA) and Wood-Ljungdahl pathway (WLP) while other organisms have only either of them. Here, we wanted to elucidate why N47 has two complete pathways potentially able to oxidize acetyl-CoA. Enzyme activities were measured in cell extracts indicating a fully functional rTCA and WLP. To elucidate the carbon flux through the pathways, cells were grown with 13C-labeled naphthalene or 13C-bicarbonate buffer. Amino acids and fatty acids were analysed for position specific 13C-incorporation with GC-MS, which indicated that in catabolism, acetyl-CoA from naphthalene was fully oxidized to CO2 via the WLP. Acetyl-CoA for anabolism of amino acids, fatty acids and carbohydrates was surprisingly not coming from the substrate naphthalene but is generated de novo by CO2-fixation, making N47 a chemoorganoauto-trophic microorganism. This indicates that chemoorganoauto-trophy can also occur with complex substrates but probably requires a complete WLP and rTCA in anaerobic microorganisms. HTML XML PDF
      PubDate: Wed, 18 Oct 2023 10:52:37 +030
       
  • Detection and Characterization of Active Microbial Cells in Salt Cavern
           Brine

    • Abstract: ARPHA Conference s 6: e108637
      DOI : 10.3897/aca.6.e108637
      Authors : Laura Schwab : Salt caverns have been used for decades as natural gas storage facilities and are now target of large-scale underground H2 storage to secure national energy transition goals. Contrary to CH4, H2 is a universal electron donor for microbial anaerobic respiration. Suitable electron acceptors are sulfate and carbonate, which dissolve from gypsum, anhydrite and lime that can make up 10 % of subsurface salt formations. Whilst sulfate reduction is inherently linked to the formation of H2S, microbial CO2 reduction can generate acetate, which can be used as carbon source by diverse microorganisms. Thus, supporting other microbial side effects, such as H2S formation, clogging and H2 consumption. However, microbial diversity and activity in salt caverns are selectively controlled by salt concentrations close to saturation and limited availability of organic carbon. If these conditions allow for microbial activity was investigated in our study.To circumvent long enrichment times associated with high salinity and limited nutrient availability, we used a stable isotope labelling approach combined with nano-scale secondary ion mass spectrometry analysis (SIP-nanoSIMS) to investigate H2-dependant microbial activity in two brine samples and compared them with that of an extremely halophilic enrichment culture (MP-32). Heavy carbonate and water (13CO2 and 2H2O) served as tracers for microbial activity. Microbial H2 consumption was additionally investigated in microcosm experiments with brine and rock salt over a period of 200 days. Setups with MP-32 served as a positive control.  Subsequently, MP-32 was selected for metagenome sequencing to explore potential metabolic pathways and strategies for osmoadaptation.Analysis of the microbial community composition in brine revealed that members of the Desulfohalobiaceae, Halobacteria and Halanaerobiales were present in all caverns and their relative abundance increased during incubation with H2 as electron donor although sulfate reduction was not observed. But incubation with H2 resulted in an increased uptake of 13C from 13CO2 in 1.6 to 3.6 % of the cells compared to incubations without H2. Uptake of 2H from 2H2O was detected in 20 to 30 % of the cells and was higher when H2 was not offered as an electron donor. Similar results were obtained from the enrichment culture MP-32, which was grown in medium with reduced salinity compared to the salt cavern brine. Uptake of 13C was 10-fold higher when incubated with H2 and nearly all cells incorporated 2H with and without H2. A total of eight metagenome-assembled genomes (MAGs) with a completion of more than 90 % could be recovered from MP-32. Two of them belonged to Desulfohalobiaceae and can be characterized as autotrophic sulfate reducers by means of the Acetyl-Coenzyme A pathway that compensate osmotic stress by synthesizing small organic molecules. Collectively, our findings provide a new approach to study microbial activity that is strongly impacted by high salinity and an improved understanding of their genomic potential.  HTML XML PDF
      PubDate: Wed, 18 Oct 2023 09:26:14 +030
       
  • Elevated bacterial endospores associated with thermogenic hydrocarbon
           seeps in deep sea sediments.

    • Abstract: ARPHA Conference s 6: e108247
      DOI : 10.3897/aca.6.e108247
      Authors : Jayne Rattray, Gretta Elizondo, Kathryn Sloan, Natasha Morrison, Martin Fowler, Daniel Gittins, Jamie Webb, D Campbell, Adam MacDonald, Casey Hubert : Introduction and approachBacterial endospore distributions in marine sediments are influenced by geological conduits providing routes for subsurface to surface microbial dispersal. To examine this phenomenon in more detail, endospore abundance was determined by quantifying the biomarker 2,6-pyridine dicarboxylic acid (dipicolinic acid or DPA) in 16 deep sea sediment cores from hydrocarbon prospective areas in the NW Atlantic Ocean. DPA is specific to endospore-forming bacteria from the phylum Firmicutes and constitutes a significant percentage of endospore dry weight. DPA is therefore a potential biomarker for sediment dwelling endospores and geological conduits.Piston cores (10), gravity cores (3) and box cores (3) were collected during two expeditions to the Scotian Slope in the NW Atlantic Ocean off the east coast of Canada aboard the CCGS Hudson in 2016 and 2018 (Campbell (2016), Campbell and Normandeau (2018), Campbell and MacDonald. (2016)). Sampling sites were 1970 to 2791 m water depth, with piston cores (n=3) ranging from 344 to 953 cmbsf and gravity cores (n=10) ranging from 43 to 739 cmbsf, box coring captured the top 25 cmbsf. To address the efficacy of DPA biomarker analysis as a tool for hydrocarbon seep location we established a modified Tb3+ chelation method (Lomstein and Jørgensen (2012), Rattray (2021)). Sediment samples were extracted using acid hydrolysis, chelated with Tb3+ and analysed using HPLC fluorescence, measuring at 270 nm emission and 545 nm excitation. DPA concentrations were converted to Endospore numbers were calculated using 2.24 fmol DPA per endospore (Fichtel 2007), a conversion factor routinely used in other studies (Braun 2017, Gittins 2022, Heuer 2020, Lomstein 2012, Rattray 2022, Wörmer 2019, Lomstein and Jørgensen 2012). DPA concentrations were compared with measurements of over 250 different gaseous and liquid hydrocarbon compounds used to assess for the presence of thermogenic hydrocarbons.Results and discussionSamples and locations were assessed as being thermogenic hydrocarbon gas positive (stations 16-41, 18-07) or thermogenic hydrocarbon negative based on the abundance of C1-C5 hydrocarbons in sediments sampled from the same cores. Station 18-14 contained hydrocarbons from biogenic origin. Station 18-06 is the only site with higher endospore abundance but that was determined to be hydrocarbon negative.Deep water Scotian Slope sediment cores show high endospore abundance correlates with thermogenic hydrocarbon seeps (Fig. 1). Cores from locations lacking evidence for thermogenic hydrocarbons generally contained significantly lower endospore abundances, with the notable exception of site 18-06. This potential paleoenvironmental hydrocarbon seep site highlights the utility of a DPA proxy for potentially identifying ancient hydrocarbon seeps and investigating past geological systems. The association of high endospore abundances with thermogenic hydrocarbons and the quantity of gas expulsion points to an interesting new biological tool for understanding hydrocarbon seepage in the deep biosphere, based on DPA assays in marine sediments. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Investigating Manganese-oxidizing microbial Biofilms in a historic Copper
           Mine of Upper Frankonia

    • Abstract: ARPHA Conference s 6: e108107
      DOI : 10.3897/aca.6.e108107
      Authors : Tillmann Lueders, Christopher Mechela, Felix Beulig, Martin Obst : Providing evidence for presumed chemolithoautotrophic manganese oxidation remains a major and challenging objective in subsurface microbiology. Here, we report on the dissection of blackish, leathery microbial biofilms discovered in the “Goldene Falk”, a historic copper mine in Northern Bavaria, with mine shafts originating back to the 15th centrury. Biogeochemical analysis of the biofilm indicated a notable enrichment of manganese oxides (MnOX), with Mn making up for more than 10% (dry weight) of the deposits. STXM analysis suggested a clear biogenic origin of MnOX in situ. Characteristic nodules of MnOX with microbial cells attached were also found in aerobic Mn-oxidizing enrichment cultures set up in minimal media in the lab. The biofilms obtained from the mine were also subjected to amplicon and metagenomic sequencing,revealing a vast diversity of presumably chemolithoautotrophic and heterotrophic microbial lineages, including members of the Pyrinomonadaceae, Rhizobiales, Methylomirabilaceae and also lineages within the Nitrospiraceae previously reported to be associated with lithotrophic Mn oxidation. We reconstructed>100 high-quality bacterial genomes (MAGs), many of them carrying genomic signatures of biogenic Mn oxidation (albeit non-lithotrophic). We continue to investigate the biofilms, our enrichment cultures and the metagenomic data obtained from the mine for further evidence of possible autotrophic manganese oxidation, the macroscopic leathery biofilm representing a likely habitat for these still enigmatic microbes. Indications for nitrogen and sulfur cycling also ongoing in the biofilms will also be discussed. This research contributes to a better understanding of the yet-enigmatic capacities of the microbiota in man-made subsurface environments. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Updates on microbial Iodine Cycling in snotty Biofilms of a prealpine
           Mineral Spring Cavern

    • Abstract: ARPHA Conference s 6: e108241
      DOI : 10.3897/aca.6.e108241
      Authors : Tillmann Lueders, Clemens Karwautz, Barbara Bekwinknoll, Felix Beulig, Baoli Zhu : We have previously described the massive, methane-oxidizing microbial biofilms discovered in the cavern of an iodine-rich former medicinal spring in prealpine southern Germany (Karwautz et al. 2017). Next to up to 3000 ppm of methane in the cavern atmosphere, the mineral spring water can contain up to 23 mM of iodine, ~thousand-fold higher than in natural freshwaters. Since reactive iodine species can be toxic for microbes, the massive microbial growth in this cave is a fascinating phenomenon. We postulate that microbes capable of utilizing different iodine species should be prevalent in the cavern. Here, we present our recent work investigating the possible involvement of biofilm microbiota in either oxidative or reductive iodine cycling. Gradient tubes set up with iodide and oxygen as redox partners showed ample microbial growth and the formation of elemental iodine. Amplicon sequencing suggested different Alpha- (Magnetospirillum spp.) and Gammaproteobacteria (Aeromonas spp.) to be capable of iodide oxidation. Moreover, we address a possible iodate-dependent methane oxidation hosted within biofilm microbiota. Metagenomes allowed to assemble the MAGs of a novel member of the recently discovered anaerobic Methylomirabilota methanotrophs, Candidatus Methylomirabilis iodofontis. Its genetic repertoire included not only known markers of oxygenic denitrification and aerobic methane oxidation, but also of iodate respiration (Zhu et al. 2022). Our ongoing work will provide further evidence of the still largely uncharted iodine-cycling ecophysiologies of the biofilm microbiota of this unique microbe-dominated subsurface ecosystem. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • From the Mountain to the Valley - Drivers of Groundwater Prokaryotic
           Communities along an Alpine River Corridor

    • Abstract: ARPHA Conference s 6: e108227
      DOI : 10.3897/aca.6.e108227
      Authors : Clemens Karwautz, Alice Retter, Johannes Haas, Steffen Birk, Christian Griebler : Rivers extend into the underlying groundwater which represents the unseen freshwater majority. Understanding microbial community composition and dynamics of shallow groundwater and lotic ecosystems is thus crucial, due to their potential impact on ecosystem processes and functioning.A 300 km section of the Mur river valley, from 2000 m.a.s.l. in the Austrian alps to the flats (200 m.a.s.l.) at the Slovenian border, was followed, analyzing river water from 14 stations and groundwater from 45 wells in early summer and late autumn. The active (RNA derived) and total prokaryotic communities were characterized using high-throughput gene amplicon sequencing. Key physico-chemical parameters and stress indicators were recorded. The groundwater microbiome is analyzed regarding its composition, change with land use, and difference to the river. Community composition and species turnover differed significantly. At high altitudes, dispersal limitation was the main driver of groundwater community assembly, whereas in the lowland, homogeneous selection explained the larger share. Land use was a key determinant of the groundwater microbiome composition. The alpine region was more diverse in prokaryotic taxa, with some early diverging archaeal lineages being highly abundant. This dataset shows a longitudinal change in prokaryotic communities that is dependent on regional differences affected by geomorphology and land use. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Soil management effects on soil organic matter properties and carbon
           sequestration (SOMPACS)

    • Abstract: ARPHA Conference s 6: e108213
      DOI : 10.3897/aca.6.e108213
      Authors : Jerzy Weber, Peter Leinweber, Yakov Kuzyakov, Edyta Hewelke, Magdalena Frąc, Michael Hayes, Vaclovas Boguzas, Andy Gregory, Lilla Mielnik, Urszula Norton, Maria Jerzykiewicz, Magdalena Debicka, Elżbieta Jamroz, Irmina Ćwieląg-Piasecka, Andrzej Kocowicz : SOMPACS is a project recommended by EJP SOIL for funding under the 1st External Call "Towards Healthy, Resilient and Sustainable Agricultural Soils". The goal of this project is to assess management practices that enrich organic matter pools that are resilient to rapid microbial decomposition. The project started in 2022 as a consortium of 12 research institutions from Poland, Germany, Ireland, Lithuania, UK, Italy and USA for a period of three years.Soil and vegetation samples from eight long-term experiments that differ in soil management practices (i.e., conventional vs. no-tillage; mineral vs. organic fertilization; with and without catch crop; and arable land vs. undisturbed grassland) are investigated. Study sites include: 22- and 54-year long experiments in Lithuania; 26-year long experiment in Italy; 30- and 40-year long experiments in Ireland; 30- and 46- and 100-year long experiments in Poland; and 178-year long Broadbalk experiment in Great Britain. Additional experimentation includes assessing the impact of root growth promoting amendments (commercially available humic substances, biochar and biogas digestate) on stable organic matter pools. In parallel with soil sampling, plant productivity are measured in all field experiments. This investigation is couples fields studies with small-scale experimental plots and laboratory incubations under controlled conditions. In addition to assessing basic soil properties, the following state-of-the-art analyses are conducted:SOM composition and stability by Py-GC-MS;fractionation of aggregate size classes and C pools of increasing physicochemical protection;isotopic analysis of δ13C and δ15N performed on different SOM pools;microbiological properties (community-level physiological profiling, selected functional genes involved in C and N cycles, microbiome and mycobiome analyses by next-generation sequencing, genetic diversity using terminal restriction fragment length polymorphism);enzymatic activity;soil water retention and soil water repellency;mineral composition of clay fraction; (8) soil structure stability.The most resistant SOM pool (humin) are isolated by different methods (isolation vs. extraction) and examined for chemical composition and structure, using spectrometric and spectroscopic techniques (mass spectrometry, NMR, FTIR, EPR, UV-Vis-NIR, fluorescence). The carbon stocks in the soil profile will be evaluated and the carbon extractable in cold water will be determined to assess the potential carbon leaching and microbial availability. Additionally, in-field soil carbon dioxide (CO2) fluxes from selected experiments is monitored.Thus far, soil samples (0-100 cm depth) were collected and the humin fraction from surface A horizon was isolated for spectroscopic studies. Crop yield and vegetation productivity was also assessed.The research was financed by NCBR (EJPSOIL/I/78/SOMPACS/2022). HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • On the presence and detectability of polyphosphates in soil microbial
           biomass

    • Abstract: ARPHA Conference s 6: e108187
      DOI : 10.3897/aca.6.e108187
      Authors : Petr Čapek, Adéla Tupá : Polyphosphates (PolyP), i.e. phosphate polymers, are commonly found in pure cultures of various microorganisms. Although they have been the subject of intensive microbiological research in the past, they have never been directly studied in species-rich soil microbial communities. So far, there are only few studies indirectly suggesting that soil microorganisms build up PolyP as a storage for phosphorus (P), and use them when soil P availability decreases. We attempted to provide direct evidence for PolyP presence in soil microorganisms, and test if the PolyP can be detected in the soil microbial biomass P pool applying the standard chloroform-fumigation extraction method. Twelve different soil samples were collected along the gradient of forest recovery after the bark beetle outbreak in the catchments of two adjacent glacier lakes (Plešné and Čertovo, Bohemian forest, Czech Republic). The presence of PolyP in the samples was assessed by staining in a manipulative experiment designed to deplete any PolyP present. Carbon (C), nitrogen (N), and P in the microbial biomass were estimated by the chloroform-fumigation extraction method and soil slurries of fresh samples stained by the Neisser method. The soils were then mixed with sterile sand and supplemented with growth medium without P. The rate of growth of microbial biomass was estimated from oxygen consumption during one week incubation at dark. After one week, the microbial biomass C, N, and the P were estimated again and samples stained. The combination of the incubation experiment and staining proved that the soil microorganisms in the collected samples contained PolyP and that PolyP were used to achieve maximum growth rate under P-limited conditions. The C to N to P ratio increased significantly over one week of incubation reflecting the changing PolyP content. To further confirm that the fumigation extraction method is sensitive to PolyP content, manufactured PolyP was added to all soils at different steps of the fumigation extraction method, and its recovery was estimated. Recovery ranged from 80 to 100%. Abiotic depolymerisation at acidic conditions required for the correct quantification of P-PO4 using molybdenum-blue method was very likely responsible for half of the recovery, the remaining being enzymatic depolymerisation. We conclude that PolyP are ubiquitous in soils and affect microbial biomass P estimation. The high recovery rate of PolyP around 90% implies that presence of PolyP can cause a significant overestimation of the microbial biomass P when typical correction factor 0.4 is used. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Differences Between Heterotrophic and Nitrate-dependent Iron-oxidizing
           Microbial Communities in Bioreactor Sediment Treating Mine Wastewater

    • Abstract: ARPHA Conference s 6: e108177
      DOI : 10.3897/aca.6.e108177
      Authors : Hannah Koepnick, Brent Peyton, Ellen Lauchnor : Nitrate-dependent iron oxidation (NDFO) is a novel mechanism for microbial bioremediation of metal and metalloid contaminants. During NDFO, microbes catalyze a redox reaction wherein nitrate is reduced to nitrite and nitrogen gas while Fe(II) is oxidized to solid Fe(III) hydroxide minerals. Metalloid contaminants such as selenium and arsenic have a propensity for adsorption to iron minerals produced during NDFO; some contaminants may also be concurrently bioreduced. A number of bacterial isolates have been shown to be capable of NDFO (e.g., Kappler et al. (2005), Kiskira et al. (2017)), but little work has been done to date characterizing mixed microbial communities performing NDFO. Some autotrophic communities have been characterized, with high relative abundances for strains of Gallionellaceae in both a freshwater sediment enrichment culture and an activated sludge culture (Blöthe and Roden 2009, Tian et al. 2020). In mixotrophic activated sludge cultures, the concentration of Fe(II) amendment was found to significantly impact microbial community composition; these cultures were fed with methanol in addition to Fe(II), and the dominant community members were Methyloversatilis and other methylotrophic strains (Liu et al. 2018). The work presented here examines microbial communities performing NDFO in the context of remediation, and in particular how differences between NDFO and heterotrophic communities may influence remediation effectiveness.This research characterizes and compares microbial communities performing NDFO versus heterotrophic denitrification during removal of selenium and nickel from mining wastewater. Sediment and influent water from a subsurface bioreactor treating mining wastewater were used to construct batch bioreactors, which were amended with selenium and nickel as well as either Fe(II) or methanol to investigate contaminant removal and microbial community composition in NDFO versus heterotrophic microbial communities. Both Fe(II) and methanol reactors removed total aqueous selenium to below the quantification limit, but Fe(II) reactors removed it more rapidly, likely due to adsorption of selenite. For nickel, removal to below the detection limit was achieved with methanol amendment, while Fe(II) amendment resulted in 42-95% removal. This was likely due to precipitation of nickel sulfide during sulfate reduction in methanol-amended reactors.DNA from the batch bioreactors will be sequenced and the results analyzed for differences among communities. Permutational multivariate analysis of variance and non-metric multidimensional scaling will be used to determine significant correlations of community composition with experimental variables, selenium and nickel removal, and NDFO (Roberts 2023, Kruskal 1964). Indicator species analyses (De Cáceres et al. 2010) will be applied to identify taxa found significantly more often (i.e., at a higher relative abundance) in one group of microbial communities than in any other group. The indicator species analysis may reveal whether there are groups of denitrifiers that predominate in NDFO conditions vs. groups that predominate during heterotrophic denitrification. The results of these microbial community analyses, in combination with the geochemical analyses, will improve our understanding of microbial communities performing NDFO in remediation environments. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • The Geochemical Habitats that Favored the Origin of Thermophilic
           Lineages 

    • Abstract: ARPHA Conference s 6: e108175
      DOI : 10.3897/aca.6.e108175
      Authors : Daniel Colman, Lisa Keller, Eva Andrade Barahona, Emilia Arteaga Pozo, Brian St. Clair, Alysia Cox, Eric Boyd : Evidence in the fossil and isotopic records suggests that life inhabited hot springs by ~3.5 Ga. Further, phylogenetic evidence places Bacteria and Archaea from high temperature environments as among the earliest evolving lineages. Moreover, contemporary hot spring communities host an extensive level of biodiversity coinciding with extensive geochemical variation due to spatial and temporal heterogeneity in available oxidants and reductants generated by variable mixing of reduced volcanic and oxidized meteoric fluids. Thus, thermophilic archaeal and bacterial lineages have been co-evolving with their hydrothermal environments since early in the history of life and through dramatic changes in Earth’s geologic history. Yet, little is known of the environmental characteristics that enabled the extensive diversification of microbial life and their metabolic functionalities in these environments. To begin developing a framework to understand the environmental characteristics that enabled expansive microbial taxonomic and functional innovation in thermophilic lineages - coordinated geochemical, metagenomic, and phylogenetic analyses were conducted on 37 high-temperature Yellowstone National Park (YNP) hot spring ecosystems that spanned the range of geochemistry (pH ~1.5-10) in YNP springs. Considerable variation in dissolved solutes and gases were identified, consistent with spatial and temporal variation in the geological, geochemical, and hydrologic processes that influence the YNP hydrothermal system. Shotgun sequencing and bioinformatics analyses yielded 1,154 archaeal and bacterial metagenome-assembled-genomes (MAGs) from the 37 springs. Genomic diversity and metabolic functions encoded by the MAGs were not uniformly distributed among spring types based on geochemistry, with moderately acidic springs (pH 5-7) harboring the greatest overall diversity, despite these spring types being relatively rare among continental hydrothermal systems. Phylogenomic analyses of MAGs indicated that their divergence times (estimated by distance to phylogenetic roots) were variable, but highly associated with spring geochemistry. Specifically, spring types hosting the highest genomic, taxonomic, and functional diversity also predominantly harbored microbial lineages with the oldest inferred divergence times. In addition, MAG-encoded metabolic functions related to carbon fixation, methane, sulfur, iron, arsenic, hydrogen, and nitrogen metabolism were discretely distributed across spring geochemical types. The distribution of metabolic functions coincided with variation in spring geochemical parameters related to those metabolisms. For example, iron metabolism was most prevalent in acidic springs exhibiting the highest iron concentrations, gas metabolism was most prominent in moderately acidic springs that exhibited the highest dissolved gas concentrations, and arsenic metabolism was prevalent among alkaline pH springs where arsenic concentrations were highest. Lastly, preliminary comparisons of microbial communities from YNP and other global continental hydrothermal systems suggest that geologic setting (e.g., bedrock type) significantly influences hot spring geochemistry and ultimately, microbial compositional and functional profiles that coincide with distinct evolutionary trajectories of hot spring taxa and functional genes. Results will be discussed in the context of the early evolution of life and the co-evolution of microbial lineages and their geologic settings in hydrothermal systems. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Gene Expression in Cadmium Sulfide Biological-Nanoparticle Hybrids

    • Abstract: ARPHA Conference s 6: e108174
      DOI : 10.3897/aca.6.e108174
      Authors : Amelia Danzinger, Robert Barnes, Stephen Larter, Steven Bryant, Casey Hubert : Through millions of years of evolution, bacteria have developed unique and complex ways to survive, allowing them to inhabit ecosystems all over the Earth, including places with high metal ion concentrations. Bacteria have developed many survival mechanisms to evade metal ion toxicity. Survival mechanisms to evade metal toxicity include the ability to transform metal ions into nanoparticles. When metal ions bind to other constituents to form nanoparticles, the metal ion concentrations in the environment can be lowered, in turn lessening the likelihood of cells encountering toxic concentrations of metals. These nanoparticles can be expelled by the bacteria into the environment, remain inside the bacteria, or attached to the cell surface. Bacteria and metal nanoparticles have many useful functions on their own. Furthermore, these functions can be combined when the two come together. Cells that produce metal nanoparticles that remain attached to their surface are referred to as biological-nanoparticle hybrids (bionanohybrids), as shown in the scanning electron image in Fig. 1. Surface-associated nanoparticles (SANs) can enhance biological functions, enabling a variety of new applications related to bioremediation, energy production and storage, and agricultural and medical advances. Bionanohybrid research also creates new opportunities to investigate microbial communities, synthetic biology, and the origins of life. Metal-sulfide SANs are of particular interest due to their semi-conductor abilities and examples of their generation by multiple bacterial species. This includes bacteria inhabiting metal-rich extreme environments like the Mariana Trench, to bacteria found in the human gut (such as E. coli). While these bacteria are very different, they do share in common the cysteine desulfhydrase enzyme—which plays a crucial role in the formation of metal-sulfide bionanohybrids. Cysteine desulfhydrase converts the amino acid cysteine into sulfide that then reacts with environmental metal cations to create metal sulfide nanoparticles (Raouf Hosseini and Nasiri Sarvi 2015). Under the right conditions (e.g., optimal ratios of metal and cysteine to cell density and growth phase), the resulting nanoparticles remain attached to the surface of the cell, as shown in Fig. 1 (Barnes et al. 2022). Despite the emergence of bionanohybrid applications, very little is known about how the bionanohybrid lifestyle impacts cells. This project aims to uncover some of the fundamental questions regarding bionanohybrid gene expression by analyzing the RNA transcripts from E. coli K-12 cells with different degrees of cadmium sulfide (CdS) SAN coverage. Gene expression studies may reveal fundamental differences between bionanohybrids and uncoated bacteria, potentially informing development of industrially advantageous bacteria strains that can produce more SANs.Gel electrophoresis and/or density gradient centrifugation will be used to separate cells that are uncoated, lightly coated, medium coated, and heavily coated proir to RNA isolation and purification. Scanning electron microscopy will confirm SAN coverage in these different fractions. RNA sequencing will indicate if there are any differences in gene expression between uncoated cells and bionanoybrids, as well as examine if SAN cell coverage has any relationship to  gene expression. This research promises to open doors to new applications related to bionanohybrids while expanding our knowledge of microbial biology. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Genomic Approaches and Analyses of Slow-Growing Obligate Iron-Metabolizing
           Microbes

    • Abstract: ARPHA Conference s 6: e108172
      DOI : 10.3897/aca.6.e108172
      Authors : David Hsu, Abhiney Jain, Halle Kruchoski, Daniel Bond, Jeffrey Gralnick : The biogeochemical cycling of iron is a vastly important process that has been a major factor defining life on Earth both before and after the Great Oxidation Event. While both abiotic and biotic factors contributing to the iron cycle have been studied for many years, the bulk of studies on iron metabolizing organisms has focused on a select few, easily manipulated model organisms. Recent discoveries have identified several unique and difficult to work with organisms from iron rich environments that survive solely on iron as either an electron acceptor or donor. The Fe(III)-reducing, Gram-positive Firmicute Metallumcola ferriviriculae MK1 was recently isolated from the Soudan Underground Mine in northern Minnesota from brine waters that intersect 2.7 Ga banded iron formations within the Canadian Shield. M. ferriviriculae MK1, which grows anaerobically using Fe(III)-citrate as its sole electron acceptor, is also mesophilic, spore-forming, culturable, and rich in multiheme cytochromes. Multiheme cytochromes are a well-established mechanism for Fe(III) reduction among the model Gram-negative microbes, such as Shewanella oneidensis and Geobacter sulfurreducens, but is poorly studied in Gram-positives. While the slow growth times of M. ferriviriculae MK1 make it difficult to study in the laboratory, the genome encodes homologs to multiheme cytochromes utilized by G. sulfurreducens for Fe(III) reduction. Specifically, two gene clusters (MK1_2258-2259 and MK1_2264-2265) each encode proteins homologous to the b-type cytochrome domain (60% and 61% sequence similarity, respectively) and c-type cytochrome domain (44.9% and 47.14%, respectively) of cbcL, which is used for reduction of mid-range redox potential acceptors in G. sulfurreducens and MK1_1670 is homologous to imcH (54.3% sequence similarity), which is used for higher redox potential acceptors. Additionally, the MK1 genome contains genes associated with sporulation, including genes encoding the master sporulation regulator spo0A, the peptidoglycan remodeling enzymes spoIID, spoIIP, and spoIIM, the spore morphogenesis protein spoIVA, and the small, acid-soluble spore proteins sspA, sspB, sspC, sspD, and sspF. Extraction and isolation of MK1 spores will facilitate evaluation of sporulation and germination conditions to shed light on a crucial preservation mechanism from an organism found in an environment with limited nutrients. Further evaluation into this novel organism can also give us insights into the microbial impacts on the iron cycle in the deep terrestrial biosphere. Another microbe of interest that was isolated from an iron-rich environment is the obligate Fe(II)-oxidizing Mariprofundus ferrooxydans PV-1, which was enriched from iron-rich mats associated with hydrothermal vents at the Kama’ehuakanaloa Seamount (previously Lo’ihi) in Hawaii. M. ferrooxydans PV-1 is a stalk-forming Fe(II)-oxidizing microbe and the first Zetaproteobacterium characterized. While M. ferrooxydans PV-1 can reliably be grown (doubling time of ~12 hours) in liquid medium traditional genetic methods are challenging because it does not make colonies on agar plates. To identify essential and non-essential genes, we developed a conjugation method using E. coli and successfully generated a transposon library in M. ferrooxydans. Libraries were grown under kanamycin selection with Fe(II)-chloride as the sole electron donor and samples isolated for analysis at two different timepoints. Deep sequencing of the mutant population at these timepoints was performed and the reads were mapped back to the M. ferrooxydans PV-1 genome to identify transposon insertion sites. Initial evaluation of the reads has identified 31 transposon insertion sites found within both the first- and second-generation populations, with 21 hits representing stable insertions in non-essential genes, including a predicted malate dehydrogenase (SPV1_772) and a predicted phospholipase (SPV1_8286), that may be useful future targets for gene insertion sites. Further evaluation comparing the read depth between the generations should identify genes that were selected for or against during the subculturing. These studies and approaches are providing insights into the roles these challenging, non-model organisms are performing in iron-rich environments, which provides a better context for the biogeochemical cycling of iron in relevant biospheres. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Characterization of DNA Degrading Microorganisms from Dewar Creek Hot
           Springs in Western Canada

    • Abstract: ARPHA Conference s 6: e108170
      DOI : 10.3897/aca.6.e108170
      Authors : Sabina Pang, Triet Tran, Robert Bowers, Tanja Woyke, Peter Dunfield : Historically, discovery and subsequent characterization of microbial species relied on pure cultures. Some challenges associated with creating pure cultures have been overcome with advances in culture independent and DNA-based molecular methods such as single-cell genomics, metagenomics, or large scale amplicon sequencing. With these advances, the rate of discovery of new species from genomic data has quickly outpaced the number of organisms with cultured representatives. As description and characterization still rely on cultures, our understanding of yet uncultured species is greatly lacking. Major lineages in the bacterial domain equivalent to phyla that lack any cultured representatives are termed “candidate phyla.” Candidate phyla are found across the bacterial tree of life, and many uncultured organisms are found to be dominant in understudied environments. Extreme environments such as thermal springs are an example of understudied environments, making them excellent environments for studying novel microbial lineages. The objective of this research is to characterize uncultured bacterial lineages from Dewar Creek hot spring in Western Canada, with a focus on DNA and protein metabolizing bacteria. Based on previous genomic data from organisms in this hot spring, we hypothesize that the candidate phylum S2R-29, with extremely low GC content, metabolizes extracellular DNA or proteinDewar Creek is a thermal spring located in the Purcell Wilderness Conservancy in British Colombia, Western Canada. It is one of Canada’s hottest springs, reaching temperatures of up to 83˚C. Samples of DNA extracted from the Dewar Creek hot spring were PCR-amplified with primers for the v3v4 region of the 16S rRNA gene to detect S2R-29, and then sequenced on an Illumina Miseq. S2R-29 was found in samples ranging in temperature from 60˚C to 77 ˚C. In addition to samples from Dewar Creek, samples from other thermal springs in Canada, as well as samples from springs in New Zealand are also being sequenced with the same primers to determine the prevalence of this candidate phylum in other similar environments. This will give a better idea of the growth conditions and range of this organism.Previously, S2R-29 single amplified genomes (SAGs) were generated from Dewar Creek samples. Analysis of these SAGs suggests that S2R-29 has the potential to use peptides and DNA as carbon sources (Fig. 1). To test the potential to metabolize DNA and protein, enrichments of samples with 13C labelled dNTPs or 13C labelled protein have been started. These enrichments will be used for stable isotope probing (SIP) to determine if any organisms in Dewar Creek are metabolizing dNTPs or protein. In addition to SIP, primers specific for S2R-29 for quantitative PCR (qPCR) have been designed and will be run on the enrichments to determine if there are any changes in the abundance of S2R-29 over time in these enrichments, further testing the metabolic potential of these organisms. Finally, probes for fluorescence in situ hybridization (FISH) will be designed for S2R-29. These will be used to perform FISH with samples from Dewar Creek in order to visualize this candidate phylum. With this research, we hope to characterize this novel phylum, and possibly discover other novel lineages of DNA- and protein- metabolizing bacteria in Dewar Creek. This research will help better understand these processes in understudied environments as well as aid our understanding of the roles that bacterial metabolisms might play in biogeochemical cycles such as biodegradation of organic matter. In all, we hope that this research gives insight into the kinds of lifestyles bacteria have evolved in order to thrive in high temperature environments. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Nitrate stimulated microbial and viral activity and the subsequent
           influence on uranium mobility in sedimentary systems

    • Abstract: ARPHA Conference s 6: e108169
      DOI : 10.3897/aca.6.e108169
      Authors : Karrie Weber, Jeffrey Westrop, Pooja Yadav, Taylor Rosso, Vincent Noel, Arjen Van Veelen, Kristen Boye, John Bargar, Xiaoqin Wu, Romy Chakraborty : Mobilization of naturally-occurring uranium(U) has been recognized to give rise to geogenic U groundwater contamination in aquifers. In addition to carbonate ligand complexation, nitrate has been demonstrated to play a role in controlling U mobility by altering uranium solubility through redox reactions. Nitrate is a common anthropogenic contaminant often prevalent at high concentrations in alluvial aquifers overlaying managed land. Alluvial deposition processes that form these aquifers create a lithologically heterogeneous subsurface with defined contacts between sands, silts, and clays. This leads to deposition of organic carbon and accumulation of reduced metals/radionuclides, including U(IV), in the finer grained silts and clays. The addition of high nitrate porewater into uranium-bearing alluvial aquifer silt sediments stimulated a nitrate reducing microbial community capable of catalyzing U(IV) oxidation and mobilization of U into porewaters. However, metadata from an aquifer wide study and a subsequent experiment revealed that this result is concentration dependent. Low concentrations of nitrate bearing pore-water added into organic-rich, uranium bearing sediments and resulted in a decrease in dissolved U(VI), consistent with reduction. XANES analysis of sediments supported U(VI) reduction with the precipitation of U(IV). U(VI) reduction activity occurred concurrent with an increase in dissolved organic carbon (DOC) and cell and virus abundance and activity. Metagenome assembled genomes from the microbial community revealed the metabolic potential indicating complex carbon degradation, fermentation, mineralization as well as the potential for anaerobic respiration of nitrate, metal/radionuclides, and sulfate. The virome recovered from the samples indicated a change in viral community in response to nitrate amendments and viral-encoded carbohydrate active enzymes were upregulated indicating a coupled response of both viral and microbial community regulating nitrate stimulated carbon biogeochemical cycling. These data together suggest that the addition of an electron acceptor in to organic carbon reduced sediments stimulates not only microbial but also viral activity leading to upregulation of genes associated with carbon biogeochemical cycling in sedimentary systems. While genes associated with metal oxidation are observed, net reduction of uranium prevails leading to uranium immobilization at low nitrate concentrations. Thus together these data indicate a tipping point whereby the influx of nitrate into the reduced environment can influence uranium mobility in DOC and carbon cycling supporting microbial activity and reducing conditions subsurface systems. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Global distribution and diversity of antimicrobial genes across subsurface
           bacterial and archaeal metagenome assembled genomes

    • Abstract: ARPHA Conference s 6: e108167
      DOI : 10.3897/aca.6.e108167
      Authors : Brandi Kiel Reese, Megan Mullis, Jason Selwyn : Microorganisms have the capability to produce antimicrobial compounds through secondary metabolism, which are not essential within their natural environments, but have been found to have many effects on the ecosystem. Antimicrobial production genes have been identified in a wide range of microorganisms; however, research into natural ecosystems has historically been limited to continental soil environments. Antimicrobial production research has been limited in the deep continental subsurface and marine environments, especially deeply buried marine sediments. We analyzed 466 high-quality metagenome assembled genomes (MAGs) collected from continental and marine subsurface environments through the Deep Carbon Observatory’s Census of Deep Life. A total of 383 MAGs contained biosynthetic gene clusters, namely Type I and Type III polyketide synthase genes, non-ribosomal peptide synthetase genes, and other unspecified ribosomally synthesized and post-translationally modified peptide products. All of these genes were found across continental mines, subglacial lakes, hotsprings, and serpentinizing environments. These environments have previously not been investigated via metagenomics for antimicrobial gene diversity, which may be produced for competition or communication purposes. All other biosynthetic genes identified in this study were less than 50% similar to reference biosynthesis genes indicating the novelty of secondary metabolism in subsurface microorganisms. The majority of predicted antimicrobial products were found to be produced exergonically, which could indicate microbial populations use energy-conserving mechanisms to produce compounds that could offer a competitive advantage. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • The provenance of microorganisms adapted to extreme salinity, extreme
           temperature, and toxic metals within the Montney shale formation.

    • Abstract: ARPHA Conference s 6: e108166
      DOI : 10.3897/aca.6.e108166
      Authors : Gabrielle Scheffer, Jayne Rattray, Andrew Kingston, Carmen Li, Omid Ardakani, Casey Hubert : IntroductionShale oil reservoirs are hypothesized to be sterile due to the extremely high temperature, pressure and salinity within these formations (Evans et al. 2018). High concentrations of toxic metals also pose challenges that demand specific microbial adaptions (Boyd and Barkay 2012, White and Gadd 1998, Ben Fekih et al. 2018). While some microorganisms are introduced into and are selected for within shale formations during hydraulic fracturing, the possibility that certain microorganisms are pre-existing inhabitants of these formations is less clear.Here, we followed the microbial diversity of input and output fluids injected into a Montney formation shale reservoir to assess the distribution and transport of microbial populations during hydraulic fracturing. Enrichment cultures distinguished various metabolisms in the microbial populations found in different sample types, and adaptations allowing them to colonize such niches.Material and methodsFracturing fluid, drilling muds (3302 m, 3350 m and 3400 m depths), shale cuttings (rinsed from the drillings muds), shale core plugs and produced water samples (12-month period) were sampled from a Montney shale oil reservoir. Microbial community compositions were analyzed by amplicon sequencing. Metal content was analyzed by inductively coupled plasma-mass spectrophotometry. High salinity enrichments at 90°C of the drilling muds or rinsed shale samples were set up in triplicate and amended with glucose and guar gum (a mannose/galactose-based polymer used during hydraulic fracturing). Sugars were measured through spectrophotometric assays. Metagenomic analyses were performed to assess microbial gene content.Results/DiscussionProvenance of microorganisms from the Montney shale formationInput fluids (fracturing fluid, drilling muds) were revealed to be the likely source of most of the microbial diversity. However, some microorganisms were only detected in the subsurface samples. ASVs affiliated with Aurantimonas, Caminicella, BRH-c8a (Family Desulfallas) and Geotoga exhibited occurrence patterns consistent with being derived from subsurface shale formations. Geotoga has only ever been reported from oil reservoirs (Semenova et al. 2020). Analysis of produced water revealed ASVs from these groups increasing in abundance during hydraulic fracturing operations, suggesting selective pressure from oil reservoir conditions (e.g., toxic metal presence, input of saline water, temperature and pressure fluctuations). Incubations set up from drilling muds showed a preference for glucose while incubations of the rinsed shale cuttings showed a microbial preference for guar gum (i.e., mannose production; Fig. 0), reinforcing the presence of different populations being derived from surface and subsurface samples.Adaptations for life in Montney shaleWhen considering adaptations of microorganisms for environmental conditions found in oil reservoirs, it is relevant to note the presence of toxic metals such as arsenic, cadmium and mercury. Levels of all three metals were found to vary over time within the 28-day shale microbial enrichments and 12-month produced water time course analyses (Suppl. material 1). Metagenomics revealed various genes for the internalization and metabolism of all three metals within the shale microbiome (i.e., arsenate reductases, arsenite transporters, metallothioneins, mercuric reductases).In conclusion, the results of this study suggest that shale reservoirs thus might not be sterile environments, and host microorganisms are able to contend with major perturbations. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • From climate change to AMR: understanding environmental-human health
           issues in a One Health framework

    • Abstract: ARPHA Conference s 6: e108165
      DOI : 10.3897/aca.6.e108165
      Authors : Thomas Reid, Jordyn Broadbent : As the impacts of climate change intensify, our interconnectedness to the environment around us seems ever more apparent. Changing terrestrial landscapes impact adjacent aquatic ecosystems, as the terrestrial-aquatic continuum experiences the ever-pressing stresses of anthropogenic activity. In the Canadian Arctic, ancient carbon stores and contaminants such as methylmercury are emerging as permafrost thaw accelerates, changing their biogeochemical nature, impacting local communities and threatening ecological health in ways still yet to be fully understood. Awakening microorganisms in these once frozen grounds are all too eager to get to work, as scientists continue to try to understand how, where, and why climate change is impacting aquatic ecosystems across Canada. Increasing aquatic nutrient loads and chemical/biological contaminants adjacent to urban and agricultural lands also impact both ecosystem and ultimately human health. In the shadow of a global pandemic, the need to understand how environmental-human interactions impact human health is ever pressing, requiring the collective expertise of researchers across the environmental-human health landscape. Antimicrobial resistance (AMR), despite being a natural evolutionary mechanism for microbial survival in the environment, has been increasing in presence and prevalence in healthcare systems worldwide, resulting in drug-resistant infections that can be fatal. As such, there is a need to understand AMR in both its natural state within the environmental microbial biosphere, alongside those places (i.e., agricultural lands, wastewater treatment outflows etc.) where humans have introduced co-selective agents such as metals, antibiotic residues and other compounds that can further facilitate and even promote resistance activity in the natural environment (Fig. 1). This connection between the human health landscape and the environment around us is a vital part of understanding the risks of both climate change and AMR, requiring an integrated and collaborative One Health approach across disciplines. Here we present research associated with our Genomics Research and Development Initiative programs using novel genomics tools and large-scale laboratory simulations to better understand the impacts of climate change and AMR in a multi-disciplinary environmental context. This work helps fullfil the need to understand the dynamics of these two global threats in an trans-disciplinary nature, drawing on the expertise of environmental microbiologists, hydrologists, bioinformaticians, and water quality experts, in tandem with public health and infectious disease experts to better understand how these threats will evolve as our planet tries to adapt to the complex stressors of the Anthropocene. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Hydrogen and Dark Oxygen drive Microbial Productivity in diverse
           Groundwater Ecosystems

    • Abstract: ARPHA Conference s 6: e108163
      DOI : 10.3897/aca.6.e108163
      Authors : S Ruff, Pauline Humez, Isabella Hrabe de Angelis, Muhe Diao, Michael Nightingale, Sara Cho, Liam Connors, Olukayode Kuloyo, Alan Seltzer, Samuel Bowman, Scott Wankel, Cynthia McClain, Bernhard Mayer, Marc Strous : Around 50% of humankind relies on groundwater as a source of drinking water. We investigated the age, geochemistry, and microbiology of 138 groundwater samples from 87 monitoring wells (
      PubDate: Tue, 17 Oct 2023 19:00:00 +030
       
  • Prominence of Candidate Phyla Radiation (CPR) in Alberta Groundwater

    • Abstract: ARPHA Conference s 6: e110344
      DOI : 10.3897/aca.6.e110344
      Authors : Damon Mosier : Groundwater is an essential part of everyday life, serving as agricultural irrigation, supporting numerous industrial processes, and providing drinking water for many. It is also home to a diverse range of unexplored microbial communities. This is especially true in Alberta, Canada, due to the rich geological history of the region and the close proximity of aquifer locations to areas ranging from oil sand-rich to agricultural to populous cities. Through collaborations with the Environment and Protected Areas division of the Alberta government we have access to more than 250 wells throughout the province, 25 of which were selected for metagenomics analysis. More than 750 metagenome-assembled genomes were recovered and coupled with historic geochemical, isotopic, and dissolved gas data, allowing us to interpret the lifestyles of microbial communities inhabiting Alberta groundwater. Results show a strong presence of organisms involved in C1-cycling, indicative of a productive subsurface environment, as well as members belonging to the Candidate Phyla Radiation (CPR). We explore likely roles of CPR, including their potential for ecological interactions via secondary metabolites. This research shows that Alberta groundwater is home to diverse, productive microbial communities that have the capacity to further our knowledge in microbial ecology. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Microbial Diversity, Biomass, and Community Structure Differences among
           Restored and Natural Saltwater Marshes, Louisiana

    • Abstract: ARPHA Conference s 6: e110263
      DOI : 10.3897/aca.6.e110263
      Authors : Susan Pfiffner, Audrey Paterson, Tommy Phelps, Annette Engel : Tidally influenced, saltwater marsh construction projects are being completed in Louisiana to combat coastal erosion and land loss, as well as to restore critical fisheries and counteract ecosystem injuries caused by oil spills and other anthropogenic activities. Historically, metrics of success for restored marshes have been based on the amount of aboveground biomass, survival of planted vegetation, and recruitment of local endemic versus invasive species. The microbial communities responsible for cycling nutrients within restored soils are not typically evaluated. Therefore, we investigated microbial community structure, biomass, and diversity in marsh soils that had been created from nearby dredge material over the past 10 years in the Lake Hermitage, West Point a La Hache area, and compared the results to those from natural marsh soils from Bay Batiste, as determined using phospholipid fatty acid (PLFA) and gas chromatography/mass spectrometry (GC/MS) techniques and from 16S rRNA gene profiles. Soils were collected from two depths (0-2 cm and 8-10 cm) from four sampling locations along a 100-m transect that extended inland from the coastline. Soil organic carbon content and soil pH were consistently lower at restored sites compared to natural marshes. Natural marsh soil microbial diversity strongly correlated with the biomass of typical marsh plants (e.g., Spartina alterniflora, Juncus roemerianus), whereas restored soil diversity correlated to higher Paspalum spp. (crowngrass) and Schoenoplectus pungens (common bulrush) biomass. Created soils had higher overall microbial diversity, but natural marsh soils had at least twice as much PLFA biomass than the created marshes at the shallow depth and 10X more biomass at the deeper depth. Biomass estimates ranged from below detectable levels to 6 x104 pmol PLFA gdw−1, with shallower soils from all sites exhibiting higher biomass (average 104 pmol PLFA gdw-1) compared to deeper soils (average 103 pmol PLFA gdw-1). Diverse PLFA profiles were observed. Shallow soils were dominated by terminally-branched and midchain-branched saturates that are indicative of Gram-positive microorganisms and actinomycetes. The shallow soils contained polyunsaturates indicative of phototrophs. Deeper soil profiles were dominated by monounsaturates associated with Gram-negative bacteria and sulfate- and metal-reducing bacteria. These monounsaturates contained on average 7% of the total PLFA profile as cyclopropyl fatty acids, which likely indicated anaerobic processes and the presence of nutritional stress. The shallow natural marsh soils exhibited more mid-branched saturates, branched monounsaturates, and polyunsaturates, whereas the shallow created marsh soils had more terminally-branched saturates. In the deeper soils, the natural marshes exhibited more terminally-branched saturates and monounsaturates, but the created marshes contained more saturates. GC/MS analyses of dimethyl disulfide derivatizations revealed shifts in microorganisms, as indicated by the types and bonding positions of monounsaturates, and the changes in the presence/absence of methanotrophic populations within the soils, which was also reflected in the 16S rRNA gene profiles. From these results, the microbial communities from the created marsh soils were different than the natural soil communities, and may reflect not being the best desired outcome for marsh restoration. With time, the expectation would be that created marsh above and belowground microbial diversity and biomass would begin to mimic natural marshes, but continued monitoring through time will be necessary to understand how these linkages develop and affect basic soil processes, nutrient cycling, and recruitment and sustenance of higher organisms like fish or crustaceans. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Microbial community ecosystem network model for chemical energy transport

    • Abstract: ARPHA Conference s 6: e108960
      DOI : 10.3897/aca.6.e108960
      Authors : Mayumi Seto, Michio Kondoh : Microorganisms thriving in low-energy ecosystems have evolved diverse strategies to sustain life, including individual-level energy conservation, optimizing energy utilization through interspecies competition, and mutually beneficial interspecies syntrophy. This study introduces a novel community-level strategy to enhance energy efficiency. We employed an oxidation-reduction (redox) reaction network model to capture the intricate metabolic interactions within microbial communities. Our findings highlight the importance of microbial functional diversity in facilitating metabolic handoffs, leading to an improved energy utilization efficiency. Moreover, the mutualistic division of labor and the resulting complexity of redox pathways actively facilitate material cycling, thereby enhancing energy exploitation. These findings provide new insights into the potential of self-organized ecological interactions to develop efficient energy utilization strategies, with significant implications for the functioning and evolution of microbial ecosystems. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Viruses, Vesicles, and other Biological Nanoparticles: The Sub-cellular
           Biosphere of a Deeply Buried 2km-Deep, 20-Million-Year-Old Coalbed
           Community

    • Abstract: ARPHA Conference s 6: e109928
      DOI : 10.3897/aca.6.e109928
      Authors : Donald Pan, Shun’ichi Ishii, Miho Hirai, Miyuki Ogawara, Wenjing Zhang, Eiji Tasumi, Fumio Inagaki, Hiroyuki Imachi : Horizontal gene transfer is an important driver of adaptation and evolution in microorganisms. Transducing biological nanoparticles such as viral particles are believed to be key facilitators of horizontal gene transfer. In deep subseafloor sediments, energy can be highly limiting, supporting only extremely slow metabolisms. In such low-energy, isolated environments where communities may subsist for millions of years, the mechanisms of subsurface microbial adaptation and evolution remain a mystery. Virus particles have been found everywhere that life has been found, including deep subsurface environments. Although microorganisms are abundant and active in the Earth's subsurface, the role of viruses in shaping and influencing these slow-growing communities is only recently starting to be explored. Here, we analyzed the deeply buried microbial community from a lignite coalbed layer 2km below the seafloor offshore Shimokita, Japan (IODP Expedition 337) that had been buried for 20 million years. We harvested cells (>0.2µm) and biological nanoparticles (
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Vegetation communities and summer net ecosystem CO2 exchange on western
           Axel Heiberg Island, Canadian High Arctic

    • Abstract: ARPHA Conference s 6: e109612
      DOI : 10.3897/aca.6.e109612
      Authors : Theresa Gossmann, Christopher Omelon : Climate change is expected to result in the Arctic transitioning from a carbon sink to a carbon source environment, with models predicting half of the carbon stock of the upper 3 m soil layer to be released by the year 2300 (van Huissteden and Dolman 2012). However, uncertainty in latitudinal warming and changes in Arctic ecosystem functions, such as gross carbon ecosystem exchange (GEE), are poorly understood, in part a reflection of a high variability in vascular plant community diversity that is dependent upon and sensitive to physiographic controls, such as soil moisture, topography, and seasonal active layer depth (Walker et al. 2005). This heterogeneity complicates assessments of carbon fluxes on a landscape scale and how they will change in the future (Shaver et al. 2007), especially given their sensitivity to local changes in climate, such as warming and higher rates of rainfall (Bintanja 2018, Bintanja and Andry 2017). As part of the creation of a long-term ecological and environmental monitoring program at the McGill Arctic Research Station at Expedition Fiord, western Axel Heiberg Island, field-based studies in 2021-2022 of plant surveys and summer net ecosystem CO2 exchange monitoring were undertaken to:define the major vegetation communities;quantify and investigate CO2 fluxes with chambers and their analogous biophysical variables; andupscale plot level CO2 measurements to the landscape scale using high spatial resolution remote sensing data.The Expedition Fiord area is recognized as a polar oasis, with high plant species richness existing within an environment of heterogeneous physiography. At the moment, five vegetation communities have been identified (xeric dwarf shrub barren, xeric-mesic dwarf shub barren, mesic dwarf shrub tundra, cassiope heath, and sedge meadow) that varied as a function of species diversity, percent cover, soil moisture, and net ecosystem carbon exchange. Barren vegetation communities having stronger respiration fluxes (i.e., carbon source environments) while more vegetated communities have stronger photosynthesis fluxes (i.e., carbon sink environments). Landcover classification revealed with high accuracy (79.3%) that barren ground and barren vegetation communities cover a much larger area compared to wetter habitats. Upscaling summer season measured carbon fluxes based on the landcover map revealed that Expedition Fiord is a carbon source environment, with an average efflux of +94.6 g CO2/day. Ongoing work focuses on the expansion of carbon flux and subsurface monitoring locations, as well as studies of soil carbon and microbial diversity across the different land cover classifications, which will help to better resolve how soil microorganisms, plant detritus, labile organic carbon, soil moisture, slope, aspect, and bedrock geology influence CO2 fluxes throughout the summer season in this high Arctic setting. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Microbial reduction of synthetic Biogenic Iron Oxides containing various
           amounts of Organic Carbon and Silica

    • Abstract: ARPHA Conference s 6: e109448
      DOI : 10.3897/aca.6.e109448
      Authors : Daniela Quintero, Danielle Fortin : Iron oxides formed in close association with bacteria are referred to as biogenic minerals (BIOS). Both the organic part of BIOS and the iron oxide particles affect the net surface charge of those iron-organic carbon aggregates and offer reactive sites that can immobilize many soluble contaminants (Warren and Haack 2001) making BIOS a contender in bioremediation technologies. However, before using BIOS in bioremediation, it is essential to understand the interactions of impurities such as organic matter and other minor components (including silica) (Dyer et al. 2010). This project involves the synthesis of Biogenic Iron Oxides (BIOS) using various silica contents and different soluble alginate concentrations (as an analogue for bacterial exopolysaccharides) close to natural environmental conditions. The mineralogical, chemical and physical composition of the synthesized samples was determined by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM), Fourier-transform Infrared Spectroscopy (FTIR), and with a Malvern Zetasizer Nano instrument. The various samples (mainly ferrihydrite) were then reduced in the presence of Shewanella putrefaciens CN32, a well-known iron reducing bacterium. All microbial reduction experiments (see Table 1) with different types of BIOS were performed under anoxic conditions.Results indicate that the ratio of organic matter and silica to Fe (III) in BIOS affects the reduction rate. It is proposed that alginate binds to iron oxide particles and protects them from reduction. However, samples in presence of high concentration of silica (i.e.,> 0.05) showed structural disorder which likely prevented nucleation of well ordered ferrihydrite, which in return increased their rate of reduction. In addition, higher reduction rates of ferrihydrite were reported at higher concentrations of silica in BIOS, even in the presence of alginate. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Organic Solvent Contamination in Groundwater Around Natural Gas Plants

    • Abstract: ARPHA Conference s 6: e109376
      DOI : 10.3897/aca.6.e109376
      Authors : Maurice Shevalier, Hugh Abercrombie : Alberta is a province that has vast deposits of natural gas. However, in its natural form it is considered sour in that it has impurities, i.e., it contains hydrogen sulphide (H2S), carbonyl sulfide (COS), carbon dioxide (CO2), mercaptans and organic sulphides. To enable the marketing of the natural gas these impurities must be removed using organic compounds and solvents. As a result of spills, leakage during processes, seepage from unlined storage ponds some of these solvents have contaminated groundwater around natural gas processing facilities.Remediation of the organic solvents is a difficult problem. To achieve an understanding of the processes involved in their degradation, a hydrogeochemical assessment of a site can be done using existing data from the site to track the development of groundwater redox zones across the different hydrostratigraphic units (HSU). This is relevant because the oxidation is hypothesized to have contributed to the biodegradation of the compounds. The objective of this global assessment is to assign a groundwater redox zone for each sample, with special emphasis placed on defining the oxidative groundwater zone (OGZ) due to its relevance to biodegradation. Ideally, the oxic groundwater zone would be defined based on the concentration of molecular oxygen (i.e., dissolved ) in groundwater (McMahon and Chapelle 2008). However, molecular oxygen, normally measured as ‘dissolved oxygen’, was not routinely measured as a field parameter in this study and therefore was unavailable to define the OGZ.The scheme adopted considers the concentrations of terminal electron acceptors (TEA) present in groundwater and measured in commonly measured parameters including oxygen, nitrate, and sulphate and dissolved metals (manganese and iron). These TEA's are consumed under progressively more reducing conditions after oxygen reduction is complete in the order: nitrate reduction, manganese reduction, iron reduction, sulphate reduction, and finally carbonate reduction (one form of methanogenesis). The results show that redox zonation is heterogeneously distributed across the site, both within and between HSUs. Multiple lines of hydrogeochemical evidence support buffered aerobic biodegradation at the site. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • The impact of subsurface life on ghost-rock karstification processes and
           cave formation

    • Abstract: ARPHA Conference s 6: e108695
      DOI : 10.3897/aca.6.e108695
      Authors : Guillaume Peugnet, Céline Pisapia, Laurent Bruxelles, Cédric Champollion, Philippe Vernant, Léna Lecourt, Bénédicte Ménèz, Emmanuelle Gérard : Karst systems represent an important carbon and freshwater reservoirs. Although karst systems have been studied for many years, a new paradigm has emerged that suggests some of them could be formed by ghost-rock processes (Dubois et al. 2014). Contrarily to the classical total karstification, ghost-rock karstification leaves in place a weathered rock, called the ghost-rock, that can constitute a microbial habitat (Spilde et al. 2005). The first results of a geomicrobiological study of the Sterkfontein’s cave system in South Africa show that these ghost-rocks are mainly composed of iron and manganese oxides mixed with organic matter of putative microbial origin (Pisapia et al. in prep). To further understand the microbial community inhabiting these ghost-rocks, its specificity compared to groundwater, and its functional impact on the karst system of Sterkfontein, a metagenomic analysis from both ghost-rocks and groundwater samples was performed. It was completed by laser microdissection of the microorganisms attached to the mineral particles, followed by whole-genome amplification and transmission electron microscopy to analyze both the nature of the mineral particles and the microorganisms associated with them. The results highlight the differences in community between these two environments (with higher abundance of Actinobacteriota and Acidobacteriota in ghost-rock samples compared to ground water in particular), and suggest a high importance of microbe-minerals interactions in the ghost rocks, through metallophores production and extracellular electron transfer processes between bacteria and metallic ions. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Identifying Putative Subsurface Microbial Drivers of Methane Flux on Earth
           and Mars

    • Abstract: ARPHA Conference s 6: e109203
      DOI : 10.3897/aca.6.e109203
      Authors : Haley Sapers, Victoria Orphan, John Moores, Lyle Whyte, Mathieu Côté, Daniel Fecteau, Frédéric Grandmont, Alex Innanen, Calvin Rusley, Michel Roux : On Earth microorganisms are critical drivers of the methane cycle, both producing and consuming methane (Boetius et al. 2000, Knittel and Boetius 2009, Orphan et al. 2001). Molecular and isotopic-based investigations of archaeal-bacterial consortia catalyzing the anaerobic oxidation of methane (AOM) in marine methane seeps identified the pivotal role of these microorganisms in mitigating the release of methane into the atmosphere (Knittel and Boetius 2009, Orphan et al. 2001). In the marine environment, AOM is predominantly carried out by closely associated consortia of methanotrophic archaea (ANME) and sulfate reducing bacteria (SRB) coupling methane oxidation to sulfate reduction in the absence of oxygen.Wolf Spring (WS), Axel Heiberg Island, Nunavut is a hypersaline cold spring methane seep and the only known terrestrial permafrost hosted methane seep known to host ANME-1 archaea associated with AOM (Niederberger et al. 2010, Magnuson et al. 2022). Wolf Spring is an unparalleled analogue for putative subsurface brines and sites of methane release on Mars. Enigmatic observations of methane in the near-surface Martian atmosphere remain a tantalizing potential biosignature.The combination of field site characterization, microbial microcosm experiments, and in situ methane monitoring represents a coordinated interdisciplinary effort to identify methane driven microbial metabolisms not only critical to understanding methane flux in the Arctic, but also as possible drivers to the methane cycle on Mars. Detailed microbial characterization of these springs has identified a chemotrophic community dominated by sulfur cycling (Altshuler et al. 2022, Niederberger et al. 2010). To date, microbial and geochemical characterization has been carried out on sediment samples to a few centimeters depth. This study expands on these initial studies, with the successful collection and analysis of deeper sediment cores at WS focusing on AOM activity to better understand the microorganisms involved and the methane cycling capacity at depth.Two decades of observing methane on Mars (Mumma et al. 2009) have generated data indicative of a dynamic, geochemical system characterized by a profile similar to the release of methane from seeps on Earth (Etiope and Oehler 2019) producing both distinct pulses known as plumes and slow background seepage. These observations suggest as of yet unknown geochemical and potentially geobiological methane sources and sinks.While methane can be produced abiotically (Etiope and Lollar 2013), on Earth most methane is biogenic. Determining the biogenicity of CH4 is non-trivial and requires a correlated approach including determination of carbon isotopes. In terrestrial systems, biogenic CH4 is 13C depleted. To characterize methane sources and sinks on Mars, near surface measurements at a frequency not possible with existing instrumentation are required.We are currently developing off-axis integrated cavity-enhanced output (OA-ICOS) spectrometry as a portable trace gas analyzer capable of obtaining high frequency measurements of methane at the sub-ppb level (Sapers et al. 2021). Optimizing OA-ICOS trace methane measurements at WS will help refine sensitivity and measurement cadence in a Mars-like environment as well as providing new remote methane monitoring capabilities for Arctic methane emissions. We are currently developing in situ 12CH4:13CH4 capabilities using OA-ICOS technology. The importance of δ 13C as a biosignature is summarized in Fig. 1. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Illegal Dumping of Oil and Gas Wastewaters Alters Semi-Arid Soil Microbial
           Communities

    • Abstract: ARPHA Conference s 6: e109202
      DOI : 10.3897/aca.6.e109202
      Authors : Denise Akob, Mitra Kashani, Mark Engle, Douglas Kent, Terry Gregston, Isabelle Cozzarelli, Adam Mumford, Matthew Varonka, Cassandra Harris : The Permian Basin, underlying New Mexico and Texas, is one of the most productive oil and gas (OG) provinces in the United States. Oil and gas production yields large volumes of wastewater with complex chemistries. The environmental health risks posed by these OG wastewaters are not well understood, particularly in the case of accidental or intentional releases. Starting in November 2017, 39 illegal dumps of OG wastewater were identified in southeastern New Mexico that released approximately 6.4x105 liters of fluid onto desert soils. To evaluate the impacts of these releases on soils, we analyzed changes in soil geochemistry and microbial community composition by comparing soils from within OG wastewater dump-affected zones to corresponding unaffected zones with no known releases. We observed significant (p
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Acetylenotrophic and Diazotrophic Bradyrhizobium sp. Strain I71 from
           Trichloroethylene-Contaminated Soils

    • Abstract: ARPHA Conference s 6: e109201
      DOI : 10.3897/aca.6.e109201
      Authors : Denise Akob, John Sutton, Timothy Bushman, Shaun Baesman, Edina Klein, Yesha Shrestha, Robert Andrews, Janna Fierst, Max Kolton, Sara Gushgari-Doyle, Ronald Oremland, John Freeman : Acetylene (C2H2) is a trace constituent of Earth’s modern atmosphere and is used by acetylenotrophic microorganisms as their sole carbon and energy source (Akob et al. 2018) Acetylenotrophs hydrate acetylene through a reaction catalyzed by acetylene hydratase, which is a heterogeneous class of enzymes. As of 2018, there were 15 known strains of acetylenotrophs including aerobic species affiliated with the Actinobacteria, and Firmicutes and anaerobic species affiliated with the Desulfobacterota. However, we hypothesized that there was an unknown diversity of acetylenotrophs in nature. We recently expanded the known distribution of acetylenotrophs via the isolation of the aerobic acetylenotroph, Bradyrhizobium sp. strain I71, from trichloroethylene (TCE)-contaminated soils (Akob et al. 2022). Strain I71 is a member of the class Alphaproteobacteria, and this is the first observation of an aerobic acetylenotroph in the Proteobacteria phylum. The isolate grows via heterotrophic and acetylenotrophic metabolism, and is diazotrophic, capable of nitrogen fixation. Acetylenotrophy and nitrogen fixation are the only two enzymatic reactions known to transform acetylene, and this is only the second isolate known to carry out both reactions (Akob et al. 2017, Baesman et al. 2019). Members of Bradyrhizobium are well studied for their abilities to improve plant health and increase crop yields by providing bioavailable nitrogen. The unique capability of Bradyrhizobium sp. strain I71 to utilize acetylene may increase the genus’ economic impact beyond agriculture as acetylenotrophy is closely linked to bioremediation of chlorinated contaminants (Mao et al. 2017, Gushgari-Doyle et al. 2021). Based on genome, cultivation, and protein prediction analysis, the ability to consume acetylene is likely not widespread within the genus Bradyrhizobium. These findings suggest that the suite of phenotypic capabilities of strain I71 may be unique and make it a good candidate for further study in several research avenues such as contaminant biodegradation and nutrient cycling. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Assessment of the in situ biomethanation potential of a deep aquifer used
           for natural gas storage

    • Abstract: ARPHA Conference s 6: e109175
      DOI : 10.3897/aca.6.e109175
      Authors : Magali Ranchou-Peyruse, Marion Guignard, Pierre Chiquet, Pierre Cézac, Anthony Ranchou-Peyruse : In response to the challenges of sustainable development and the H2 sector, it is foreseeable that H2 will be stored into geological storage, such as deep aquifers. However, CO2 evolves in deep aquifers because it may be naturally present there; it may also be a constituent of the stored gas mix, or could even be voluntarily stored in the context of the fight against global warming. Autochthonous microorganisms can consume them as sources of energy and carbon (methanogens, (homo)-acetogens and sulfate-reducers). This was already demonstrated in a previous experiment (Haddad 2022) and under operating conditions (Lobodice, Czech Republic ; Smigan 1990).Understanding these mechanisms and quantifying them appear necessary to assess the modifications generated by this type of microorganisms on the properties of the gas. The methanogenesis reaction (CO2 gas + 4H2 gas → CH4 gas + 2H2O liquid) induces a lowering of pressure, since 5 gas molecules are transformed into a single gas molecule: CH4 (water being condensed at subsurface conditions). In situ biomethanation technique could represent a potential on several scales larger than conventional catalytic or biological methanation reactors, due to the very large reservoir volumes involved. Biomethanation in geological reservoirs would enable us to reduce our consumption of fossil fuels, so as not to emit more CO2, while meeting the growing energy needs of a region and ensuring its independence from hydrocarbon-producing countries.A deep aquifer already used as UGS was selected for this study. Formation waters from 17 control wells in this aquifer (Fig. 1) were sampled to assess the potential activity of indigenous methanogenic populations, as well as sulfate-reducers. Despite relatively low sulfate concentrations for a deep aquifer (0.025-1.35 mM), sulfate reducers were found at all sites targeting and quantifying the dsrB gene, which is characteristic of this metabolic group (between 1.8∙101 ±2.0x100 and 1.3∙104 ±2.0∙103 dsrB gene copy numbers.mL-1). In contrast, methanogenic archaea based on the mcrA gene quantification were detected at only 10 of the 17 sites (up to 4.3∙102 ±8.3∙101 mcrA gene copy numbers.mL-1). The choice was made to focus the rest of the study on 7 of these 10 sites. The potential for methanogenesis was assessed on cultural tests with formation water alone or supplemented with calcite (CaCO3), a mineral present in the formation. Results indicate that initial times and controls are controlled by the sulfate variable, since the latter was not consumed by sulfate-reducers. Biotic trials in the presence of calcite and H2/CO2 (abiotic controls and final times) are logically characterized by higher concentrations of calcite, bicarbonate and calcium, but this is not the case for trials in the presence of H2 alone. We therefore deduce that methanogenesis took place mainly via gaseous CO2, but that without the latter, calcite was a source of carbon for lithoautotrophs. Cultures incubated with H2 as the sole gas phase have the highest methane concentrations, logically associated with the lowest sulfate concentrations (consumed by sulfate-reducers), the lowest Eh (probably due to the presence of sulfides) and more alkaline pH values up to 10 (which may have led to precipitation of carbonate and calcium ions). All the sites studied showed sulfate consumption and methane production. Analysis of taxonomic diversity (MiSeq; 16S rRNA gene V4-V5) showed the dominance of three genera of sulfate-reducers with Thermodesulfovibrio-Desulfovibrio-Desulfotomaculum and methanogenic populations belonging to the Methanobacterium genus.These initial results show a strong potential of in situ biomethanation for the deep aquifer studied. All these experiments were carried out at near-atmospheric pressure, and the results still need to be confirmed and refined in the laboratory under conditions that simulate real-life conditions as closely as possible (rock, pressure, nature of gases). HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Chemolithoautotrophic Organic Matter Contributions to Subterranean Food
           Webs Dominated by Filter-feeders

    • Abstract: ARPHA Conference s 6: e109094
      DOI : 10.3897/aca.6.e109094
      Authors : Hannah Rigoni, Helena Bilandžija, Annette Summers Engel : IntroductionMost groundwater and cave ecosystems depend on an influx of allochthonous, surface-derived organic matter sourced by diffuse flow through overlying rock and soil or by localized flow from the surface into sinkholes or entrances. The amount of organic matter entering the subsurface is usually low, resulting in oligotrophic conditions and food scarcity that affect community members' dispersal and colonization patterns. In situ, chemolithoautotrophically-produced organic matter has the potential to supplement organic matter pools in the subsurface, especially if the surface and subsurface are hydrologically disconnected. Chemolithoautotrophic contributions are less understood for most groundwater and cave ecosystems, especially from ecosystems dominated by sessile filter-feeders that cannot easily move to search for food. Our study focuses on uncovering the microbiology and organic matter contributions in Croatian Dinaric Karst caves, specifically in the Neretva and Lika River basins, that contain the only subterranean serpulid tube worm, Marifugia cavatica, the only known cave-adapted freshwater bivalves, Congeria kusceri and Congeria jalzici, and stygobitic and stygophilic sponges, Eunapius subterraneus and Ephydatia fluviatilis, respectively.MethodsWe collected surface water, invertebrates, and representative examples of surface organic matter, as well as subsurface water, stygobionts, biofilms, and sediments from Pukotina u Tunelu Polje Jezero in the Neretva River basin and Markov Ponor and Susik Ponor in the Lika River basin. To evaluate microbial communities, 16S rRNA genes were sequenced, analyzed using mothur to obtain operational taxonomic units (OTUs) at 99% sequence similarity, and classified with the SILVA v138.1 reference database. We used the program FAPROTAX and recently published literature to identify putative metabolisms for OTUs, focusing on identifying chemolithoautotrophic functions. We measured stable carbon (δ13C) and nitrogen (δ15N) isotope compositions to assess potential food sources for the stygobionts from surface and subsurface materials.We compared microbial community diversity among caves and sample types using non-metric multidimensional scaling (NMDS) on a Bray-Curtis dissimilarity matrix of rarefied presence/absence data. Analysis of similarity (ANOSIM) on the dissimilarity matrix was used to compare sample type and cave. Welch's t-test was used to compare differences in isotopic composition between surface and caves, and Kruskal-Wallis was used to compare differences among caves. Markov Chain Monte Carlo simulations were employed using mixSIAR v3.1.12, with a chain length of 100000, to calculate the contribution of food sources using a diet tissue discrimination factor of δ13C=1.2±0.39‰ and δ15N=4±0.18‰. All analyses were performed in R using vegan (v. 2.6.4) and stats (v. 4.2) packages.Results and DiscussionMicrobial community composition varied significantly among sample types in each cave (ANOSIM; R=0.74, p
      PubDate: Tue, 17 Oct 2023 17:45:15 +030
       
  • Legume-cereal intercropping as a strategy of regenerative agriculture
           supporting reverse of biodiversity loss - relevance of microbiome-based
           research

    • Abstract: ARPHA Conference s 6: e108886
      DOI : 10.3897/aca.6.e108886
      Authors : Magdalena Frąc, Jacek Panek, Agata Gryta, Karolina Oszust, Giorgia Pertile, Dominika Siegieda, Mateusz Mącik, Michał Pylak, Shamina Imran Pathan, Giacomo Pietramellara : Adverse environmental impacts connceted with high chemicals and fertilizers use is one of the causes of biodiversity loss. Therefore, there is a need to looking for more natural and non-hazardous alternative approaches to make agriculture more sustain. The legume-cereal intercropping is currently one of the „hot topics” in the area of sustainable and regenerative agriculture. These intercropping practices are increasingly gaining attention as a way for enhancing soil ecosystem services and reversal biodiversity loss, as well as as a strategy of harnesing plant yield quality and soil health.Legume-cereal systems are the most common intercropping combinations used in sustainable agriculture models because of their noncompeting niche requirements and atmospheric nitrogen fixation which improve a balance of this nutrient in soil and plant and decrease the amount of mineral fertilizers use. However, conventional crop rotations in the EU are largely dominated by cereals while legume cultivation has declined in recent years.The idea of the LEGUMINOSE project includes that multi-species assemblages of plants deliver rhizosphere functions that are greater than the sum of the functions delivered by the rhizospheres of individual plants growing alone as a monoculture. We hypotheses that the higher plant diversity in intercropping will increase plant health, improve soil biodiversity and reduce the use of pesticides in agroecosystems. However ther is a knowledge gap concerning plant-soil-microbe interactions under root exudation from single and diverse plant assemblage and role of soil microbiomes in soil ecosystem functionality and plant production. Therefore we will focus on understanding these interactions by the microbiome research of soil and plant niches, including bulk soil, rhisozphere, roots and shoots of cereal and legume plants in order to assess the percentage of microbiota transfered between them within monocropping and intercropping fields and understand relationships of that microbiomes in plant health improvement. This project will design and implement sustainable environmental practices based on legume-cereal intercropping systems that account for the nature, impacting to global biogeosphere changes.Research funded in the frame of Horizon Europe Programme, agreement no. Project 101082289 — LEGUMINOSE. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Improving our Understanding of Environmental Stress Impacts
           and Responses of the Microbiome

    • Abstract: ARPHA Conference s 6: e108809
      DOI : 10.3897/aca.6.e108809
      Authors : Christopher Weisener : Over the course of this century, it will be important to identify cost effective/low maintenance solutions for treating contaminants in receiving watersheds. Adopting these strategies will involve a better understanding of what defines a “natural” environment compared to these contaminated sites. Traditional geochemical testing and standard microbial community analyses (e.g., DNA profiling) or using isolates can be limited with respect to their ability to infer real-time, active processes of bacterial communities. In recent years the application of genomics to identify the microbial microbiome in anthropogenic stressed conditions has advanced considerably. In many cases, the activity of microorganisms will directly impact the chemical conditions in both surface and subsurface water column and contaminated sediment environments controlling the fate of nutrients and contaminants alike. Questions arise such as:What are the baselines or reference systems that can be used'What indices can be used to study the long-term and short-term controls on the mobility, cycling, and bioavailability of toxic metals and organic contaminants'In many cases the balance of chemical oxidizing and reducing components in water will control the development of chemical and nutrient gradients observed in either natural and/or applied systems (e.g., constructed wetlands or bioreactors). In these cases, biogeochemical systems will determine the direction and onset of specific metabolic pathways as defined by their favorable thermodynamic outcome, an issue for most bioremediators (i.e., microorganisms). Also, the degree of chemical alteration (toxicity or degradation products) can be directly linked to the proportion of their biological activity. In this presentation, contrasting case studies highlighting natural (baseline) and anthropogenically impacted landscapes will be discussed. The focus will be on identifying and linking physicochemical processes to microbial community function using emerging omics for geochemical applications and ascertaining novel contaminant bioindicators.  HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Using a novel approach to characterize the surface reactivities of
           silica-rich ferrihydrite and biogenic cyanobacteria-ferrihydrite
           aggregates and the implications for Archean ocean geochemistry

    • Abstract: ARPHA Conference s 6: e108666
      DOI : 10.3897/aca.6.e108666
      Authors : Yuhao Li, Lingyi Tang, Daniel Alessi, Janice Kenney, Murray Gingras, Kurt Konhauser : Precambrian banded iron formations (BIF) are iron- and silica-rich chemical sedimentary rocks that are commonly used as paleo-redox proxies for Archean and Paleoproterozoic seawater geochemistry. At the onset of the Great Oxidation Event (herein GOE) around 2.4 Ga, cyanobacteria flourished with increasing nutrient fluxes due to oxidative weathering on land. In turn, this led to increased primary productivity that facilitated the permanent shift from a reducing Earth atmosphere to an oxidizing one. Interestingly, the duration of GOE also overlapped with one of the most prolific periods of BIF deposition.It is widely accepted that cyanobacteria were likely responsible for BIF formation during the GOE. Oxidation of dissolved Fe(II) by oxygen produced from cyanobacteria forms a metastable and amorphous mineral phase ferrihydrite, Fe(OH)3. As an essential component in both ancient BIF deposits and various modern ecosystems, the surface reactivity of ferrihydrite has been extensively studied under different conditions (i.e., pH and ionic strengths). Not only are the highly reactive surfaces of ferrihydrite particles important shuttles for trace element transport from the water column to the sediment pile, but previous studies have also demonstrated that cyanobacterial cells and ferrihydrite tend to aggregate at seawater pH. This means that ferrihydrite was also a vector for the transport of organic carbon to the seafloor. However, a complicating issue is how co-ions affect the surface reactivity of ferrihydrite, specifically dissolved silica which was abundant in ancient seawater. Although previous studies have demonstrated that silica can passivate the surface reactivity of ferrihydrite, what remains unclear is how silica impacts ferrihydrite-biomass aggregation.To fill this knowledge gap, we formed both silica-spiked ferrihydrite and cyanobacteria-ferrihydrite aggregates in situ and subsequently conducted empirical potentiometric acid-base titrations and Cd adsorption experiments on the fresh aggregate samples at three different ionic strengths (0.56 M, 0.1 M and 0.01 M). We minimized sample processing (i.e., drying and powdering) to a simple washing step, in which the aggregate pellets remained hydrated to avoid any mineral transformation thus altering their true surface reactivity in seawater. Experimental results were then fitted with non-electrostatic model to predict both surface charges and metal-adsorption behavior of ferrihydrite aggregates. Different from previous surface-complexation modelling studies, here we used a novel and more powerful modelling program called Phreefit. It utilizes the global optimization algorithms instead of more commonly used Newton-Raphson method in FITEQL program, which is often too limited for precisely modelling complex systems such as the two samples in this study. Furthermore, we also measured the surface charges of both samples over the pH range from 3 to 9 on a Malvern Zetasizer and characterized the surface functional groups through Fourier-Transform Infrared Spectroscopy to help with our interpretation of the experimental data.Preliminary results show that cyanobacteria-ferrihydrite aggregates formed primarily due to ionic bridging. Cyanobacterial cells likely facilitated the precipitation of dissolved silica. Findings from titration and Cd adsorption experiments indicate that the surface reactivity and capacity of both silica-rich ferrihydrite cyanobacteria-ferrihydrite aggregates to adsorb trace elements differ from their individual components, likely due to site blockage. This distinction is particularly prominent when considering the expected Archean seawater pH from 6 to 8. This disparity implies that the biogenic ferrihydrite aggregates do not exhibit an additive surface reactivity, which is in agreement with similar previous studies. Our combined results are crucial to accurately predict the adsorption of trace elements onto the aggregate surface and, ultimately, comprehend the archive of trace elements in sedimentary rocks used to reconstruct Precambrian ocean chemistry. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • N-Alkane Biosignatures in a High Arctic Mars Analogue Gossan Deposit

    • Abstract: ARPHA Conference s 6: e108199
      DOI : 10.3897/aca.6.e108199
      Authors : Hiba Aoid, Richard Léveillé, Peter Douglas, Myriam Lemelin, Marie-Claude Williamson : If past life ever existed on Mars, what are the multiple ways it could have been preserved in the Martian geological record' This crucial question is becoming especially relevant the more we uncover about the planet’s ancient wet history. Different acidic and sulfur rich analog environments have been proposed that are comparable to the alteration environments of iron oxides and sulfate minerals on Mars. However, some authors have hypothesized that these past Martian environments might have been cold and semi-dry, similar to polar regions on Earth. As part of the T-MARS team, we studied reactive gossans in the Canadian High Arctic, on Axel Heiberg Island, as an analog environment to similar deposits on Mars. We hypothesized that n-alkane lipids could potentially be an important form of molecular fossils entombed in varying mineral assemblages of sulphates, iron oxides, and phyllosilicates in Arctic gossans, because of their excellent preservation potential relative to most other forms of organic molecules. To determine the preservation potential of lipids in mineralogically varying acidic sulfur rich gossan deposits, this study extracted and quantified n-alkane biomarkers from three different Arctic gossans with gas chromatography–mass spectrometry (GC-MS). Total organic carbon, pH, and mineralogy were also determined. Organic matter was found to be very low in all samples (
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Seasonal Relationships of Alpine Plants and Microbes through a
           Stoichiometric and Enzymatic Lens

    • Abstract: ARPHA Conference s 6: e108599
      DOI : 10.3897/aca.6.e108599
      Authors : Adam Ruka, Johannes Scheichhart, Jiří Doležal, Kateřina Čapková, Travis Meador, Roey Angel, Rosa Paulina Calvillo-Medina, Zuzana Chlumská, Nadine Praeg, Paul Illmer, Klára Řeháková : Alpine biomes experience harsh environmental conditions and short growing seasons, which necessitate interspecific and intraspecific interactions to ensure the stability of diversity and ecosystem multifunctionality. The relationship between plants and microbes in this environment is equally dynamic, with seasonal pulses of nutrients and the phenology of plants creating specific "hot moments" of biogeochemical activity. As a crucial zone of interaction between plant roots and microbial communities, the rhizosphere serves as a "hot spot" of biogeochemical cycling where the mineralization of nutrients, such as carbon, nitrogen, and phosphorus, allows for the transfer of nutrients between trophic levels. However, the nature of these interactions depends on edaphic and climatic conditions, potentially leading to cooperation or competition to meet the stoichiometric demands of organisms.Elevation gradients within alpine ecosystems provide dramatic shifts in temperature, precipitation, and soil development that allow for the study of these interactions over short geographical distances. In conjunction with seasonal sampling, this approach can provide a wide environmental context to observe the relationship between specific plants and microbial communities. By investigating the C/N ratios of plants, microbes, and soil, as well as microbial enzymatic potential, we can infer nutrient limitations, temporal niche partitioning, and biological responses to abiotic conditions.Within the Austrian Alps, we studied a selection of herbaceous plants and their associated microbial communities across an elevation gradient spanning 2200-2800 m (Fig. 1). The primary aims of the study were to assess the seasonal changes in C/N stoichiometry from both trophic levels, microbial enzymatic potential, and rhizosphere diversity of bacterial and fungal communities. To fulfill these aims, four locations were selected based on the two present biomes (alpine meadow and sub-nival zone) and the transition between them. Four to five plant species were collected during each season in 2023, including the often-neglected snow-covered winter season, along with rhizosphere and bulk soil for microbial biomass measurements and soil chemistry. Plant leaf tissue samples were analyzed using Isotope-ratio mass spectrometry for plant C/N ratios, while soil and microbial C/N ratios were calculated using chloroform fumigation extraction. Microbial enzymatic potential was assessed using hydrolase enzymatic assays for five fluorophore-labeled substrates. 16S-rRNA and 18S-rRNA genes were sequenced using an Illumina MiSeq platform from the fine roots of collected plant individuals to quantify the relative abundances of bacterial and fungal taxa.The findings of our study indicate that the higher microbial biomass (Cmic) in alpine meadow locations leads to increased enzymatic activity compared to sub-nival zones. However, specific plant species were found to enhance microbial biomass and enzymatic potential in different seasons, suggesting that plants promote microbial interaction and biogeochemical cycling during different seasons as a form of temporal niche partitioning. Most plant species demonstrated an increase in C/N ratios throughout the season, sometimes increasing by more than 200%. However, two Poa spp. showed the highest C/N ratios during the summer, which further correlated with higher microbial C/N ratios.By observing changes in stoichiometric ratios of organisms that interact and share nutrients, we propose that these relationships vary between host plants depending on their temporal niche and abiotic factors (soil and environmental conditions). Furthermore, the positive or negative correlation of plant and microbial C/N ratios may indicate the relative cooperation or competition between trophic levels. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Studying the isotopic composition of microbial methane with a
           genetically-tractable methanogen

    • Abstract: ARPHA Conference s 6: e108567
      DOI : 10.3897/aca.6.e108567
      Authors : Jonathan Gropp, Markus Bill, Daniel Stolper, Dipti Nayak : Nearly all biogenic methane is produced by a group of microorganisms called methanogenic archaea (or methanogens). Methanogens can use a variety of substrates, such as H2 + CO2, acetate, and methylated compounds, for methanogenesis. Previous studies have shown that the stable carbon and hydrogen isotopic compositions of methane produced by methanogens can vary drastically depending on the substrate composition and concentration in the environment. For instance, the concentration of H2 in the environment has a substantial impact on the isotopic composition of methane derived from hydrogenotrophic methanogenesis (reduction of CO2 to methane using H2 as the electron donor) (Valentine et al. 2004, Penning et al. 2005). While there is substantial empirical data on isotopic signatures of methane from different substrates and under different conditions, the physiological and molecular features that control these values are not as well understood. To address this, we are using the metabolically diverse and genetically tractable methanogen, Methanosarcina acetivorans as a model system to uncover key cellular processes that control the stable bulk isotopic composition of methane (i.e., 13C/12C and D/H ratios), and the distributions of the “clumped” 13CH3D and 12CH2D2 isotopologues.The methanogen M. acetivorans grows on a wide variety of compounds such as acetate, methanol, methylamines, and methylsulfides. We found that the methylotrophic pathways (for methanol and trimethylamine) and the aceticlastic pathway have large and similar primary hydrogen isotopic effects (α of ~0.45). These data are in contrast to previous findings and imply a minor isotopic exchange between CH4 and H2O (Valentine et al. 2004, Gruen et al. 2018). Focusing first on the methylotrophic pathway, we generated mutants of two key enzymes in the methylotrophic pathway: a) methyl coenzyme M reductase (Mcr) that catalyzes the last step in methanogenesis and b) methyltransferases that catalyze the first step in methylotrophic methanogenesis from methanol (Mta). A mutant with reduced Mcr expression had no observable change in the hydrogen isotopic effect relative to the wild-type, validating the initial observation of minimal H2O-CH4 hydrogen isotopic exchange. One of the Mta mutants, which only expressed a specific methyltransferase isoform, had a smaller carbon isotopic effect relative to the other isoforms (α of ~1.074 vs. ~1.080). Since the isoforms are thought to be identical in structure, the different isotopic effects could result from differential expression of each isoform, or from different kinetic properties. By combining our genetic approaches with traditional and high-resolution isotopic analytical methods, we aim to develop a quantitative understanding of the mechanisms that control the isotopic compositions of biological methane. Our preliminary results show that M. acetivorans would be an ideal candidate for such research, which could help in understanding methanogens’ physiology in natural environments in past, present, and future Earth. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Non-Deterministic Factors Affect Competition Between Thermophilic
           Autotrophs from Deep-Sea Hydrothermal Vents

    • Abstract: ARPHA Conference s 6: e108248
      DOI : 10.3897/aca.6.e108248
      Authors : Briana Kubik, James Holden : Hydrothermal vents provide windows into the rocky subseafloor on Earth and serve as terrestrial analog sites for extraterrestrial environments. By studying patterns of community assembly in hydrothermal vents and using geochemical models, we can better understand how the deep-sea biosphere contributes to local and global biogeochemical cycling and gather valuable information about how similar communities may arise on Earth and beyond Earth. One prevailing thought is that vent microbial community assembly is driven by deterministic factors such as the thermodynamic favorability of redox reactions. We hypothesized that subsurface microbial communities may also be significantly influenced by other factors, such as differential cell yields, varying optimal growth temperatures, and stochasticity.At Axial Seamount in the Pacific Ocean, H2-consuming methanogens of the genera Methanocaldococcus (Topt 82°C) and Methanothermococcus (Topt 65°C) and H2-consuming sulfur reducers of the genus Desulfurobacterium (Topt 72°C) are the most abundant autotrophs that grow optimally at or above 65°C (Fortunato et al. 2017). At one low-temperature hydrothermal vent site, Marker 113, methanogens are the predominant thermophilic autotrophs while at another site, Marker 33, thermophilic autotrophic sulfur reducers predominate. There is no apparent geochemical or thermodynamic explanation for the differences in community composition. In this study, we performed a series of co-culture competition experiments using Methanocaldococcus jannaschii, Methanothermococcus thermolithotrophicus, and Desulfurobacterium thermolithotrophum HR11 as representative methanogens and sulfur reducers common to hydrothermal vents to explain the variations in community composition between thermophilic autotrophs.M. jannaschii increases its cell yield (cells produced per mole of CH4 produced) when grown on very low H2 concentrations as part of a growth rate-growth yield tradeoff (Topçuoğlu et al. 2019). This increase in cell yield could provide methanogens with a competitive growth advantage over H2-consuming sulfur reducers, who otherwise catalyze a more thermodynamically favorable growth reaction. Competition co-culture experiments were conducted between M. jannaschii and D. thermolithotrophum at 72°C and between M. thermolithotrophicus and D. thermolithotrophum at 65°C, both at 1:1 ratios and initial aqueous H2 concentrations of 1.2 mM (high H2) and 85 μM (low H2) to determine the effects of temperature and H2 availability on autotroph competition. For both methanogens, the growth rate, maximum cell concentration, and total CH4 produced decreased when they were grown in co-culture, at low H2, or both relative to monocultures grown with high H2. The methanogen cell yields generally increased in co-culture and at low H2. At both experimental temperatures, the growth rate of D. thermolithotrophum remained unchanged in co-culture and at low H2 relative to monocultures but the maximum cell concentration decreased in co-culture relative to monocultures at both H2 concentrations. However, at low H2, both in mono- and co-culture, there was no detectable H2S produced by the sulfur reducer suggesting a significant shift in growth yield. At both temperatures and H2 concentrations, the sulfur reducer reached higher cell concentrations than the methanogens.Stochasticity or vent fluid chemistry could lead to early colonization of a vent by methanogens followed by niche exclusion of autotrophic sulfur reducers due to a numerical advantage of the methanogens. Therefore, competitive co-culture experiments were run as before at high H2 with varying initial methanogen:sulfur reducer ratios. At 72°C, D. thermolithotrophum reached the same maximum cell concentration and produced the same amount of H2S in monoculture and co-culture even when the methanogens initially outnumbered the sulfur reducer up to 10,000-fold. M. jannaschii reached a lower maximum cell concentration and produced less CH4 in all co-cultures relative to growth in monoculture. At 65°C, D. thermolithotrophum reached the same maximum cell concentrations and produced the same amount of H2S in monoculture and co-culture when the methanogens initially outnumbered the sulfur reducers up to 100-fold. However, when the methanogens initially outnumbered the sulfur reducers 1,000-fold, M. thermolithotrophicus grew as well as in monoculture and the maximum cell concentration and amount of H2S produced by D. thermolithotrophum was significantly lower than in monoculture and the other co-culture conditions.In conclusion, both methanogens and sulfur reducers shift their redox reactions away from CH4 and H2S production, respectively, and towards biomass production when H2 is limiting. This should be accounted for in thermodynamic predictive models. Furthermore, a combination of growth temperatures lower than the optimum of sulfur reducers and high initial methanogen cell concentrations relative to sulfur reducers can lead to a long-term predominance of methanogens over autotrophic sulfur reducers in vent environments through niche exclusion. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • A global atlas of subsurface microbiomes reveals phylogenetic novelty,
           large scale biodiversity gradients, and a marine-terrestrial divide

    • Abstract: ARPHA Conference s 6: e108531
      DOI : 10.3897/aca.6.e108531
      Authors : S Emil Ruff, Isabella Hrabe de Angelis, Megan Mullis, Jerome Payet, Brandi Kiel Reese, Karen Lloyd, Andrew Steen, Hilary Morrison, Mitchell Sogin, Joshua Ladau, Frederick Colwell : Marine and terrestrial subsurface sediments, rocks, and water may represent the largest habitat for microbial life on Earth. Despite the global importance of subsurface ecosystems for biogeochemical cycling and microbial diversity, essential questions remain unanswered. These concern the abundance of novel microbial clades in the subsurface, the difference between marine and terrestrial microbiomes, as well as between subsurface and surface microbiomes, and the adaptation of specific clades to environmental conditions of the subsurface. Here, we analyzed 523 archaeal and 1,211 bacterial 16S rRNA gene amplicon sequence datasets and 146 shotgun metagenomes from surface, interface, and subsurface ecosystems worldwide, including lakes, saltmarshes, hot springs, caves, mines, methane seeps, hydrothermal vents, and seafloor sediments. We found that archaeal and bacterial alpha diversity (per sample richness and evenness) and beta diversity (community differentiation) varied continuously between surface and subsurface biomes, but differed abruptly between marine and terrestrial subsurface ecosystems. Bacterial alpha diversity tended to be lower in subsurface than surface ecosystems. However, subsurface archaeal alpha diversity often exceeded that of surface ecosystems suggesting that the subsurface holds a considerable and largely underestimated fraction of Earth’s archaeal diversity. Overall, microbial communities of marine subsurface ecosystems exhibited greater alpha diversity, while gamma diversity (total richness and evenness) was higher in the terrestrial subsurface, potentially due to greater habitat diversity. We identify diagnostic clades, especially for the archaea, that are widespread in marine (e.g., Lokiarchaeia, Bathyarchaeia) and terrestrial (e.g., Hadarchaeia, Methanococci) subsurface ecosystems. The substantial community overlap along depth transects and between surface, interface and subsurface realms suggests a global gradient between the surface and subsurface rather than a discrete and defined subsurface biosphere. Finally, none of the included subsurface ecosystems seem to be exhaustively sampled, leaving much biodiversity and metabolic capability yet to be discovered. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Transformation of Benzene Derivatives in Acidic Conditions by the Fungus
           Hormoconis Resinae – Reductive, Oxidative, or Both'

    • Abstract: ARPHA Conference s 6: e108520
      DOI : 10.3897/aca.6.e108520
      Authors : Joshua Mogil, Hardiljeet Boparai, Georgina Kalogerakis, Brent Sleep : Hormoconis resinae (or Cladosporium resinae), colloquially known as the kerosene fungus, is predominantly found in fuel tanks (Rafin and Veignie 2018). Its occurrence in fuel tanks was first reported in early 1960s. Since then, it has been considered as a serious threat by the petroleum industry for bio-deteriorating fuel quality, corroding storage tanks, and clogging pumps and filters (Sheridan et al. 1971). This fungus flourishes well in the presence of water and can thrive at a wider pH range (2-10), than most commonly studied bacteria, with optimum towards the acidic end (Rafin and Veignie 2018). As a biosafety level 1 organism (ATCC 2021) with wide natural prevalence, H. resinae is both safe to study and apply in the field. Thus, it can be utilized for developing bioremediation processes suitable for petroleum-contaminated sites.Contamination of groundwater sources by fuel pollutants has been an important public health concern for decades (Mitra and Roy 2011). Several components of fuel are known to be toxic even at low concentrations with deleterious health effects including teratogenicity and carcinogenicity (ATSDR 1995). Past research has mainly focussed on the degradation of n-alkanes, a major component of fuel, by H. resinae which used the n-alkanes as sole carbon and energy sources (Rafin and Veignie 2018). Benzene derivatives like toluene, benzaldehyde, benzoic acid are also often found as fuel pollutants. Though some studies have investigated the effects of benzene derivatives on the survival and growth of H. resinae (Cofone et al. 1973, Oh et al. 2001, Qi et al. 2002), not much work has been done on their biodegradation (Kato et al. 1990).Previous study showed a reductive transformation of benzoate to benzaldehyde, benzyl alcohol, and 1-phenyl-l,2-propanediol (Kato et al. 1990). More work was needed to study the further transformation of these products. Thus, the current study focussed on the transformation of benzaldehyde and benzyl alcohol in acidic conditions by H. resinae ATCC 34066. The main objectives were to study the effects of:culture media,glucose, andoxygen enrichment on the fungal growth in the presence of these benzene derivatives and their biodegradation kinetics and pathways.Some experiments were also conducted with toluene as the contaminant.H. resinae was not able to transform toluene (1-200 ppm) at all, though it was able to grow on it in the presence of 1% glucose. The fungus was able to transform benzaldehyde (≤550 ppm) to benzyl alcohol (reductive) and benzoic acid (oxidative). Many monoaromatics such as catechol, resorcinol, hydroxybenzoic acids and aliphatic compounds such as fumaric acid, levulinic acid were also detected as the oxidation products of benzaldehyde by high-resolution liquid chromatography-mass spectrometry. The presence of glucose slowed down benzaldehyde transformation but increased the benzyl alcohol formation relative to benzoic acid, probably due to the further slower transformation of benzyl alcohol. Oxygen enrichment enhanced the benzaldehyde transformation. Glucose was a preferred culturing media as fungus grown on potato dextrose agar (PDA) showed a 5-week lag phase for benzaldehyde transformation. However, this PDA-cultured fungus, after growing on benzaldehyde, did not exhibit a lag phase and started benzaldehyde transformation immediately. Transformation of benzyl alcohol, as target contaminant, was slower and incomplete in the presence of glucose. Benzyl alcohol was transformed mainly to benzoic acid via an oxidative pathway.In summary, this study has shown that H. resinae can transform the benzene derivatives via both oxidative and reductive pathways. Moreover, H. resinae can use these compounds as sole carbon and energy sources. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Temporal dynamics of microbe-virus interactions in the Baltic Sea

    • Abstract: ARPHA Conference s 6: e108494
      DOI : 10.3897/aca.6.e108494
      Authors : Emma Bell, Karin Holmfeldt, Jarone Pinhassi, Anders Andersson : Bacteria and archaea are key drivers of all major element cycles. Viruses that infect bacteria and archaea also play a fundamental role by altering the metabolic state of their host during infection and causing cell death. The CRISPR-Cas system is one of many strategies employed by bacteria and archaea to defend against viral infection. Invading viral DNA is incorporated into a CRISPR array as a short sequence (spacer) that is then recognised during the next viral encounter providing an adaptive immunity. The temporal dynamics of this system in the environment, however, is not well constrained. Using a meta-omic dataset spanning several years of sampling, we leveraged the CRISPR-Cas system to explore microbe-virus interactions in the Baltic Sea. Our goal was to understand how quickly microbes in the environment adapt to virus predation, and conversely how quickly viruses adapt to the microbial defence mechanism by developing mutations in the spacer-targeted region. To explore these interactions, we first generated a database consisting of thousands of complete and high-quality viral genomes recovered from viromes collected from the Baltic Sea. CRISPR arrays were then identified in microbial metagenome assembled genomes (MAGs), metagenomic contigs, and unassembled metagenomic reads from corresponding sampling time points. Virus-host dynamics were uncovered by matching quality-filtered spacers from CRISPR arrays to the viral database. The results show that spacer turnover over time can be captured in temporal meta-omic datasets. In the Baltic Sea, this has implications for the termination of microbial blooms, biogeochemical cycling, and resource turnover. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • The Shoshone Canyon Conduit Cave: A Greater Yellowstone Ecosystem Sulfur
           Cave

    • Abstract: ARPHA Conference s 6: e108455
      DOI : 10.3897/aca.6.e108455
      Authors : John Spear, Sasha Robinson, Paul Slayback, Patrick Thieringer, Carmen Villarruel : Fve miles west of Cody, Wyoming and ~25 miles east of Yellowstone National Park lies the Shoshone Canyon Conduit Cave (Fig. 1, Suppl. material 1). Bisecting Cedar Mountain, an irrigation tunnel built by the Bureau of Reclamation (BoR), managed by the Heart Mountain Irrigation District, delivers water from the BoR Buffalo Bill Reservoir to more than 30,000 acres of irrigated lands in and around Cody. During the construction of that tunnel in the late 1940’s, a cave was discovered and the tunnel was made to travel though the cave with only light disturbance to the cave. The cave can only be accessed with permission in the non-irrigation time of year. The cave is rich in sulfides and sulfur deposits with unique speleothems.To date, we have conducted a preliminary geobiological survey of the geochemistry, microbiology and mineralogy of this sulfur cave on its speleothems, mineral deposits and waters. Sampled waters, of which there is little, were all highly acidic (pH < 2). Microbiologically, an analysis of microbial communities present in approximately 25 sample locations (Fig. 1) to answer the question of—who is there'—was conducted via small subunit ribosomal 16S rRNA gene (for Bacteria and Archaea) and 18S rRNA (for Eukarya) analyses, prepared using a polymerase chain reaction (PCR) primer-pair that allows for the even amplification of all three domains of life. All samples were relatively low in biomass and resultant community analysis indicates a variety of Bacteria and Archaea phyla are represented with a dominance of known sulfur metabolizers. Mineralogically, petrography reveals a variety of crystal growth and habit in this sulfur-dominated, calcium carbonate-driven karstic ecosystem. X-ray diffraction analysis (XRD) was used to better determine the kinds and extant of mineral morphotypes and were surprisingly variable. The Shoshone Canyon Conduit Cave is a most intriguing sulfur cave to reveal what is known of the geobiology of sulfur caves in the Rocky Mountain Region. Findings from this work will likely apply to other cave systems such as Villa Luz (Mexico) and the Frasassi system (Italy). Finally, to learn about the Cedar Mountain Caves will inform on how either or both the National Park Service (NPS) and Bureau of Land Management (BLM) may better manage them as a meaningful component of the Greater Yellowstone Ecosystem. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • What the Flux' – Water-Rock-Microbe Interactions and Crustal
           Gases in the Deep Subsurface

    • Abstract: ARPHA Conference s 6: e108428
      DOI : 10.3897/aca.6.e108428
      Authors : Riikka Kietäväinen : The deep, dark fracture zones of the continental crust host a fascinating interplay between water, rocks, and microbes, resulting in the production and consumption of gases, including methane, volatile organic compounds (VOCs), and hydrogen. Various geological factors influence the formation and release of these crustal gases, including the local rock type with its concentration of radioactive elements and carbon, temperature, and the connectivity and dynamics of fracture systems with each other and to the surface.To understand the formation, accumulation, and release of crustal gases, methodologies of hydrogeochemistry, biogeochemistry, and isotope geochemistry can be employed. Sample collection from drill holes and mines, coupled with on-line monitoring of gas flux rate and composition, provides important data. Furthermore, the integration of molecular biological methods enhances our understanding of the water-rock-microbe interactions that shape the deep subsurface gas realm.Crustal gases have crucial implications for life in extreme environments, including those outside of our planet Earth, but potentially also pose significant challenges to drilling, mining, and their environmental impact. Moreover, crustal gases hold relevance for the energy sector, contributing to both the long-term safety of geological disposal of nuclear waste, carbon footprint of geothermal wells, and the exploration of hydrogen as a sustainable energy resource. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Biomass distribution and activity of respective subsurface sediments and
           groundwater within a shallow subsurface ecosystem

    • Abstract: ARPHA Conference s 6: e108389
      DOI : 10.3897/aca.6.e108389
      Authors : Heidi Smith, Lauren Lui, Anna Zelaya, Isaac Miller, Charles Paradis, Torben Nielsen, Bradley Biggs, Benjamin Adler, Terry Hazen, Adam Arkin, Matthew Fields : Subsurface environments represent diverse microbial communities responsible for mediating biogeochemical cycles linked to the turnover of organic and inorganic carbon important to groundwater used by human society for consumption, irrigation, agriculture and industry. Within the different sediment environments, microorganisms typically reside in two distinct phases (planktonic or biofilm), and significant differences in community composition, structure and activity between free-living and attached communities are commonly accepted. However, largely due to sampling constraints and the challenges of working with solid substrata, the respective contributions of groundwater (planktonic) and sediment-associated (biofilm) cells to subsurface processes is largely unresolved. In order to directly compare the distribution of microbial biomass and activity in a shallow, subsurface environment, total cell numbers, translationally-active cell numbers (Bioorthogonal non-canonical amino acid tagging- BONCAT), and microbial activity (3H-Leucine incorporation) were investigated for a low biomass pristine and contaminated groundwater and corresponding soil cores. The results demonstrated that cell numbers for the 0.2 um fraction were approximately an order of magnitude higher for the pristine groundwater compared to the contaminated groundwater (106 v. 105). When contaminated groundwater was compared to the pristine, there was a drastic reduction in the BONCAT activity and the contaminated groundwater was between 100-700-fold less. Additionally, the rate of leucine incorporation (3H-leucine) on a per cell basis in pristine groundwater was up to 1,000 times greater than the contaminated groundwater, respectively. Overall, like total cell numbers, activity was lower (both per volume and per cell) in contaminated groundwater compared to pristine groundwater. In pristine soil, activity (3H-leucine) displayed steep gradients of microbial activity in association with transition zones of water table height (i.e., vadose, capillary fringe, saturated). A similar trend was also observed for the contaminated soil; however, the contaminated soil displayed an overall gradient of decreasing activity with depth. The highest activity for pristine soil was 9,253 ng C/g/d located in the transition depth between the capillary fringe and the saturated zone. Conversely, the highest activity for the contaminated soil was 9,175 ng C/g/d located in the vadose zone, perhaps the zone that is least impacted by contaminant flux. The pristine groundwater had higher activity rates than pristine sediment (per cell), but the contaminated groundwater had slower activity rates than the contaminated sediment (per cell). However, for both pristine and contaminated samples on a per volume basis, sediments had the vast majority of microbial activity compared to groundwater (80-95%). In the absence of strong selection forces compared to the contaminated well, the uncontaminated samples demonstrated more phylogenetic differences between the viable and translationally active populations that could be attributed to growth rate differences. The contaminated groundwater sample was predominated by a single, persistent Rhodanobacter strain in the viable fraction, while Rhodococcus, Brevundimonas, and Pseudomonas species dominated the translationally active fraction. Overall, the top active ASVs were prevalent and persistent across the estimated landscape. This is the first quantitative comparison between corresponding groundwater and subsurface sediments as well as predictions of viable and active ASVs (e.g., stable analog probing- SAP) within commonly used sequencing methods. The results suggest that field sampling schemes should consist of both viability and activity-based assessments that can help delineate key microbial populations within diverse microbial communities across and within subsurface systems. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Marine Cold Seeps As A Gateway Of Deep Subsurface Extremophiles To
           The Seafloor

    • Abstract: ARPHA Conference s 6: e108387
      DOI : 10.3897/aca.6.e108387
      Authors : Anirban Chakraborty, Bronwyn Ellis, Jayne Rattray, Casey Hubert : In the Earth’s deep subsurface life is comprised exclusively of microorganisms, and estimates indicate 12-45% of the global prokaryotic biomass, on the order of 1029 microbes, is found in subseafloor sediments. Investigating how this enormous microbial biomass is maintained in the extreme habitats below seafloor is critical for understanding the rules of life in the deep biosphere. Furthermore, Earth’s subseafloor habitats often present analog environments detected in other planets such as the recently discovered “ocean worlds”, i.e., planetary bodies in our solar system which consist of large subsurface oceans including Saturn’s moons Titan and Enceladus and Jupiter’s moon Europa. Therefore, investigating life in and beneath Earth’s oceans remains at the forefront of the current astrobiological research endeavors.Despite the inhospitable nature of the subseafloor sedimentary realm, active microbial populations including bacteria capable of transforming into dormant endospores have been demonstrated to inhabit deeply buried anoxic sediments and oil reservoirs, permeable ocean crust, and around hydrothermal vents. These extreme habitats often remain physically connected to the seafloor by unique geological features such as marine cold seeps that transmit hydrocarbon-rich fluids originating in deep sediment layers. It remains unclear how fluid migration in cold seeps influence the composition of the seabed microbiome and if they transport deep subsurface life up to the surface. In this study, we addressed this knowledge gap by analyzing over 180 marine surficial sediments from the Gulf of Mexico and the Monterey Bay to assess whether hydrocarbon fluid migration serves as a mechanism for the dispersal of subsurface extremophiles and their introduction into the seabed via cold seeps.Seafloor samples were collected either by piston coring or ROV-operated push coring and were stored at -20°C upon collection. Presence of hydrocarbons in the piston core sediments wa characterized by gas chromatography mass spectrometry and fluorescence spectroscopy whereas gas seepage was determined in the ROV push cores by visual confirmation of gas bubbles emanating from the seafloor. Sediment microbiome composition was determined by high throughput 16S rRNA gene amplicon sequencing. Metabolic diversity was assessed via a genome-centric metagenomics approach aided by shotgun metagenomic sequencing of selected samples. Additionally, viable bacterial endospore communities were investigated from a subset of over 120 of the above samples by allowing endospore germination using a high-temperature incubation assay followed by amplicon sequencing.While 132 of the piston core sediments contained migrated liquid hydrocarbons, evidence of continuous advective transport of thermogenic alkane gases was observed in 11 sediments. Gas seeps harbored distinct microbial communities featuring bacteria and archaea that are well known inhabitants of deep biosphere sediments. Specifically, 25 distinct sequence variants within the bacterial lineages Atribacterota and Aminicenantia and the archaeal lineage Thermoprofundales occurred in significantly greater relative sequence abundance along with well-known seep-colonizing members of the bacterial genus Sulfurovum, in the gas-positive sediments. Metabolic predictions guided by metagenome-assembled genomes suggested these organisms are anaerobic heterotrophs capable of non-respiratory breakdown of organic matter, likely enabling them to inhabit energy-limited deep subseafloor ecosystems. In addition, eight different lineages of anaerobic bacterial endospores activated by sediment incubation assays were strongly associated with hydrocarbon-bearing sediments. These lineages were most closely related to Clostridiales previously detected in oil reservoirs from around the world.These results cumulatively point to petroleum geofluids as a vector for the advection-assisted upward dispersal of deep biosphere microbes from subsurface to surface environments, shaping the microbiome of cold seep sediments and providing a general mechanism for the maintenance of microbial diversity in the deep sea. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Phytoplankton Ecology in an Oilsands End Pit Lake

    • Abstract: ARPHA Conference s 6: e108385
      DOI : 10.3897/aca.6.e108385
      Authors : Chantel C. Furgason, Angela Smirnova, Joel Dacks, Peter Dunfield : Alberta oilsands mining and extraction have produced over 1 trillion litres of tailings wastewater (AER 2021) containing several compounds of concern (Cossey et al. 2021). End-pit lakes are a low-cost, long-term proposed strategy of tailings reclamation that sequester tailings in a mined-out pit under a freshwater cap. Through dilution and biogeochemical processes, the water cap should over time develop into a functional ecosystem integrable with the local watershed (Cossey et al. 2021, Saborimanesh 2021). Established in 2012, Base Mine Lake is currently the only full-scale pilot end pit lake developed by the Alberta oilsands industry and requires further investigation to validate end pit lakes as a tailings reclamation technology (Cossey et al. 2021). The first stage of reclamation requires the development of a phytoplankton community, which serves as the base of the aquatic food web (CEMA 2012).The primary objective of this study was to characterize the phytoplanktxon community over time in BML from 2016 to 2021 to determine how community composition and abundances shift over seasons and years. Characterization used Illumina gene sequencing targeting 16S rRNA, 18S rRNA, and 23S rRNA gene amplicons, giving relative abundance data over time for phytoplankton. Cell count data was used to verify gene sequencing results. The phytoplankton community composition and diversity in Base Mine Lake was compared to those of a freshwater reservoir and a tailings pond.Analysis of gene sequencing data revealed that major genera of phytoplankton included Cryptomonas (Cryptophyceae), Choricystis  (Trebouxiophyceae), Euglena (Euglenales), and Synechococcus (Synechococcales), all of which appear to exhibit seasonal blooms during 2016-2021 (Fig. 1). Sequencing analysis also indicated that Base Mine Lake and its freshwater input source Beaver Creek Reservoir shared many of the same genera but different strains/species of those genera. This suggested that the distinct conditions in each aquatic site may have selected for distinct strains. Diversity analyses of gene sequencing data revealed that phytoplankton diversity in Base Mine Lake was intermediate between that of its freshwater input reservoir and a tailings pond. There currently exists no low-cost, large-scale treatment method that fully reclaims tailings water (Cossey et al. 2021, Saborimanesh 2021). End-pit lakes retain tailings until recalcitrant compounds are degraded to near-environmental levels (Saborimanesh 2021, CEMA 2012), but further research is required before end-pit lakes can be approved as a viable reclamation technology (Cossey et al. 2021). Although research is available now on native microbial communities in tailings waters, knowledge on their contributions to an aquatic microbial food web is limited (Saborimanesh 2021). This proposed research is the first of its kind to examine the contribution of phytoplankton to end pit lake food web ecology. This will advance knowledge of end-pit lakes as a reclamation strategy in effort to reduce the environmental footprint of tailings water. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:30:15 +030
       
  • Anabolic and Catabolic Microbial Activity in Hydrocarbon-rich Sediments of
           Guaymas Basin

    • Abstract: ARPHA Conference s 6: e108382
      DOI : 10.3897/aca.6.e108382
      Authors : Toshiki Nagakura, Yuki Morono, Motoo Ito, Jens Kallmeyer : Guaymas Basin, located in the Gulf of California, Mexico, is a young marginal ocean basin with high sedimentation rates of>1 mm/year, active seafloor spreading, and steep geothermal gradients in its sediment. It hosts a unique microbial subseafloor biosphere as these conditions lead to thermal cracking of sedimentary organic matter and the production of bioavailable organic carbon compounds and hydrocarbons already at shallow depths. The abundance and diversity of potential microbial substrates raise the question of which substrates are being used for catabolic and anabolic microbial metabolism. We thus analyzed the microbial uptake of hydrocarbons and inorganic nitrogen using nanoscale secondary ion mass spectrometry (NanoSIMS) analysis after incubation with stable-isotope labeled substrates. Incubations were carried out with samples from two International Ocean Discovery Program (IODP) Exp. 385 drill sites. Site U1545 is characterized by undisturbed sedimentary strata and a temperature gradient of 225°C/km, whereas Site U1546 has experienced a sill intrusion at greater depth, below the cored interval. The intrusion led to temporary heating of the sediment, but a temperature gradient of 221°C/km indicates thermal equilibration with the surrounding sediment since sill emplacement. Incubations were carried out with 13C-benzene + 2H-hexadecane + 15NH4Cl or 13C-methane + 15NH4Cl at in-situ temperature (4-62°C) and pressure (25 MPa) for 42 days. Additionally, sulfate reduction rates (SRR) were measured by incubating the samples with four aliphatic hydrocarbons + four aromatic hydrocarbons or methane and radioisotope-labeled 35SO42- for 10 days, also at in-situ temperature and pressure. The NanoSIMS analyses reveal that a few samples showed detectable microbial assimilation of hydrocarbons. Nitrogen was significantly assimilated in some samples incubated with methane. The assimilation mostly occurred in samples from near the seafloor (2 and 44 meter below seafloor (mbsf)). Our results indicate that anaerobic microorganisms in Guaymas Basin take up measurable amounts of hydrocarbons and inorganic nitrogen even in the relatively short incubation time of 42 days. The results of the SRR measurements indicate that a mixture of hydrocarbons and methane increases the SRR in samples from near the seafloor (2 mbsf) and around the sulfate-methane transition zone (44 and 55 mbsf) but not in samples from greater depths. Our results show that anaerobic microorganisms in Guaymas Basin can use hydrocarbons for anabolic and catabolic metabolism in this extreme environment. Given the high abundance of various carbon compounds, nitrogen appears to be a limiting factor for cellular growth. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Microbial Community Dynamics in Base Mine Lake, the First End-Pit Lake in
           the Alberta Oil sands Industry

    • Abstract: ARPHA Conference s 6: e108268
      DOI : 10.3897/aca.6.e108268
      Authors : Angela Smirnova, Peter Dunfield, Chantel Furgason, Andriy Sheremet, Felix Nwosu, Joel Dacks : Oil extraction from bitumen in the Athabasca region of northeastern Alberta, comprises a large segment of the Canadian economy. However, the process of oil extraction from surface mined oil sands ores results in diverse environmental issues including disturbance of land areas and habitats for wildlife, as well as production of large volumes of fluid tailings containing many compounds of concern for the environment. Land reclamation strategies of most oilsands operations propose the construction of end-pit lakes (EPL) to contain and biodegrade tailings, eventually becoming integrated into local watersheds. We used 16S/18S rRNA gene amplicon and metagenome sequencing to monitor prokaryotic and eukaryotic communities in the first full-scale pilot EPL of the Canadian oilsands, Base Mine Lake (BML) Fig. 1, over 6 years from 2015-2021, and compared them with communities from two active tailings ponds, Mildred Lake Setting Basin (MLSB) and Southwest in-Pit (SWIP), as well as with communities from a more natural freshwater body, Beaver Creek Reservoir (BCR). Alpha diversity in BML is intermediate to diversities in active tailings ponds and a natural lake, although highly variable with time, depth, and season. Microbial communities in BML resemble neither freshwater lake nor active tailings communities, although a structural shift of either microbial community occurred every year, and 2021 was a year of the most profound effect. Moreover, metabolic functions in BML also shifted every year, with the most dramatic shift for photosynthesis-related genes. Temporal changes among protists identified in BML were characterized by enrichment of species designated as picophytoplankton: Cryptomonas, Mychonastes, Trebouxiophyceae, and Dinobryon, and among bacterial genera by enrichment of common freshwater lake species or bacterioplankton: Ca. Fonsibacter, Sporichthyaceae, Ca. Planktophila, Microbacteriaceae ML602J-51, Ilumatobacteraceae CL500-29 group. Network analysis identified a potential microbial consortium between newly enriched species of picophytoplankton and bacterioplankton. Heterotrophic bacteria with streamlined genomes may overcome auxotrophic limitations by scavenging metabolites and other compounds produced by phototrophs presumably via chemotaxis behaviour. We propose that the formation of the consortium might serve as a biomarker for reclamation process of an oil sands tailings pond. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Rhizobiome of ‘Ōhi‘a Lehua (Metrosideros polymorpha) Offers Insight
           into Plant-Microbe-Invertebrate Interactions in the Subsurface

    • Abstract: ARPHA Conference s 6: e108263
      DOI : 10.3897/aca.6.e108263
      Authors : Annette Engel, Mireille Steck, Audrey Paterson, Amir Van Gieson, Megan Porter, Rebecca Chong : Roots are common features in basaltic lava tube caves on the island of Hawai‘i. For the past 50 years, new species of cave-adapted invertebrates, including cixiid planthoppers, crickets, thread-legged bugs, and spiders, have been discovered from root patches in lava tubes on different volcanoes and across variable climatic conditions. Assessing vegetation on the surface above lava tube passages, as well as genetic characterization of roots from within lava tubes, suggest that most roots belong to the native pioneer tree, ‘ōhi‘a lehua (Metrosideros polymorpha). Planthoppers are the primary consumers of sap at the base of the subsurface food web. However, root physicochemistry and rhizobiome microbial diversity and functional potential have received little attention. This study focuses on characterizing the ‘ōhi‘a rhizobiome, accessed from free-hanging roots inside lava tubes. Using these results, we can begin to evaluate the development and evolution of plant-microbe-invertebrate relationships.We explored lava tubes formed in flows of differing elevations and ages, from about 140 to 3000 years old, on Mauna Loa, Kīlauea, and Hualālai volcanoes on Hawai‘i Island. Invertebrate diversity was evaluated from root galleries and non-root galleries, in situ fluid physicochemistry was measured, and root and bare rock fluids (e.g., water, sap) were collected to determine major ion concentrations, as well as non-purgeable organic carbon (NPOC) and total nitrogen (TN) content. To verify root identity, DNA was extracted, and three sets of primers were used. After screening for only Metrosideros spp., the V4 region of the 16S rRNA gene was sequenced and taxonomy was assigned.Root fluids were viscous and ranged in color from clear to yellow to reddish orange. Root fluids had 2X to 10X higher major ion concentrations compared to rock water. The average root NPOC and TN concentrations were 192 mg/L and 5.2 mg/L, respectively, compared to rock water that had concentrations of 6.8 mg/L and 1.8 mg/L, respectively. Fluids from almost 300 root samples had pH values that ranged from 2.2 to 5.6 (average pH 4.63) and were lower than rock water (average pH 6.39). Root fluid pH was comparable to soil pH from montane wet forests dominated by ‘ōhi‘a (Selmants et al. 2016), which can grow in infertile soil with pH values as low as 3.6. On Hawai‘i, rain water pH averages 5.2 at sea level and systematically decreases with elevation to pH 4.3 at 2500 m (Miller and Yoshinaga 2012), but root fluid pH did not correlate with elevation, temperature, relative humidity, inorganic and organic constituents, or age of flow. Root fluid acidity is likely due to concentrated organic compounds, sourced as root exudates, and this habitat is acidic for the associated invertebrates.From 62 root samples, over 66% were identified to the genus Metrosideros. A few other identifications of roots from lava tube systems where there had been extensive clear-cutting and ranching included monkey pod tree, coconut palm, Ficus spp., and silky oak.The 16S rRNA gene sequence surveys revealed that root bacterial communities were dominated by few groups, including Burkholderiaceae, as well as Acetobacteraceae, Sphingomonadaceae, Acidobacteriaceae, Gemmataceae, Xanthobacteraceae, and Chitinophagaceae. However, most of the reads could not be classified to a specific genus, which suggested that the rhizobiome harbor novel diversity. Diversity was higher from wetter climates. The root communities were distinct from those described previously from ‘ōhi‘a flowers and leaves (Junker and Keller 2015) and lava tube rocky surfaces (Hathaway et al. 2014) where microbial groups were specifically presumed capable of heterotrophy, methanotrophy, diazotrophy, and nitrification. Less can be inferred for the rhizobiome metabolism, although most taxa are likely aerobic heterotrophs. Within the Burkholderiaceae, there were high relative abundances of sequences affiliated with the genus Paraburkholderia, which includes known plant symbionts, as well as the acidophilic genera Acidocella and Acidisoma from the Acetobacteraceae, which were retrieved predominately from caves in the oldest lava flows that also had the lowest root pH values. It is likely that the bacterial groups are capable of degrading exudates and providing nutritional substrates for invertebrate consumers that are not provided by root fluids (i.e., phloem) alone.As details about the biochemistry of ‘ōhi‘a have been missing, characterizing the rhizobiome from lava tubes will help to better understand potential plant-microbe-invertebrate interactions and ecological and evolutionary relationships through time. In particular, the microbial rhizobiome may produce compounds used by invertebrates nutritionally or that affect their behavior, and changes to the rhizobiome in response to environmental conditions may influence invertebrate interactions with the roots, which could be important to combat climate change effects or invasive species introductions. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Organomineralization of dolomite in hypersaline microbial mats from Qatar
           sabkhas visualized by TEM & STXM

    • Abstract: ARPHA Conference s 6: e108262
      DOI : 10.3897/aca.6.e108262
      Authors : Ivan Strakhov, Zach DiLoreto, Jassim Al-Khayat, Maria Dittrich : Deep insight into the low-temperature mineralization mechanism of dolomite in sediments has remained elusive. This issue is popularly termed “The Dolomite Problem” due to its multifactorial nature. Dolomite has been observed to mineralize in the exopolymeric substances produced by microbial mat communities (Bontognali et al. 2013), where productivity is high. One working hypothesis suggests that degrading organic matter in hypersaline environments releases the necessary component ions, increasing saturation with respect to dolomite (DiLoreto et al. 2019, Dupraz et al. 2009, Petrash et al. 2017). Other models suggest a dissolution-reprecipitation reaction of calcite to dolomite (Rivers 2023). High-resolution micro-spectroscopy techniques (such as transmission electron microscopy, TEM; and scanning transmission X-ray microscopy, STXM) can be used to determine chemical changes in crystals nucleating in a matrix, however to date very little studies have focused on observing dolomite mineralization at the nano-scale. The present study investigates microbial mats collected from hypersaline salt flats in the Persian gulf at micro- to nano-meter scales using high-spatial and -energy resolution TEM (Thermo Scientific Talos 200X at the Canadian Centre for Electron Microscopy) and STXM (PolLux Beamline at the Swiss Light Source at Paul Scherrer Institut), specifically to see changes in carbonate mineralization due to interactions with organic matter. C, Ca and O elemental maps of carbonate crystals were obtained with EDXS (energy-dispersive X-ray spectroscopy) in TEM. These crystals were also indexed by SAED (selected area electron diffraction in TEM). Fine spectral signatures (near-edge X-ray absorption fine structures, or NEXAFS) at the C K-edge (280-290 eV) and Ca L2,3-edge (344-356 eV) in STXM were used to determine the chemical identity of carbonate minerals and surrounding organic matter of the microbial mats.The results of the study show that dolomite nucleates in close association with the organic matter of the mats, where degradation is highest (defined in our adjacent study as the increase in C:N ratio). In TEM, polycrystalline dolomite is seen mineralizing in the matrix of the microbial mat organic material (Fig. 1). In STXM, the identity of the carbonate mineral changes from calcite on the outside to dolomite on the inside of the microbial mat particle (Fig. 2). In addition, our microsensor observations of elevated H2S concentrations, surface oxygenation from oxygenic phototrophy, high reduction potential, high organic carbon, high Mg:Ca ratio and high organic matter degradation (by C:N ratio) in each of the studied microbial mats confirms that the ideal dolomite mineralization conditions according to models of the dolomite problem are present in each case. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Microbiological Treatment of Nitrate and Selenate from Coal Mine-Affected
           Water in a Subsurface,Semi-Passive, and in situ Water Treatment Facility

    • Abstract: ARPHA Conference s 6: e108259
      DOI : 10.3897/aca.6.e108259
      Authors : Rachel Spietz, Lisa Kirk : Metallurgical coal mining generates significant amounts of waste rock, which can release nitrate and selenate upon atmospheric exposure, with resulting changes in surface water and ground water quality. Microorganisms residing on waste rock in the local subsurface have the metabolic potential to denitrifyand reduce selenium to treat mine-affected waters and stabilize waste rock. To support these processes, waste rock facilities have been designed to inject nutrients (e.g., methanol and phosphoric acid) in semi-passive water treatment of mine-impacted waters. Microbial community data regularly collected fromsubsurface semi-passive reactors throughout the startup and operations phases showed that native heterotrophic denitrifying bacteria and selenium reducing bacteria were enriched as a result of nutrient amendment. The microbial community was stable while the source water and geochemical parameters remained unchanged; however, a significant shift in the microbial community coincided with changes in the source of water treated. Metagenomic sequencing of microbial communities within the active treatment zone revealed multiple biochemical pathways of nitrate reduction. Geochemical and water quality data indicate near complete selenate reduction, yet a low abundance of in known selenate reduction genes were recovered. This may suggest that biologically mediated selenium reduction may be more widespread, both functionally and taxonomically. Further research into these pathways and mechanisms for nitrate and selenium reduction will help to strengthen our understanding of selenium reduction mechanisms and their application in mine water waste management. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Dispersal and Distribution of Thermophilic Endospores in Deep-Sea
           Ecosystems

    • Abstract: ARPHA Conference s 6: e108260
      DOI : 10.3897/aca.6.e108260
      Authors : Francesco Bisiach, Daniel Yakimenka, Casey Hubert : The distance-decay relationship is a central concept in biogeography and spatial biodiversity, describing how two distinct entities decrease in similarity as the distance between them increases. The decay of community similarity with geographical distance is driven by multiple factors, such as gene drift, environmental selection, and the accumulation of mutations over time. While the distance-decay relationship has been recognized for several decades, there are certain circumstances where the biogeographical patterns of certain species and communities cannot be predicted by this relationship. The example addressed in this project is the case of thermophilic endospore-forming bacteria found in permanently cold deep ocean sediments.Thermophilic endospores (thermospores) are routinely found on the deep ocean floor, a permanently cold environment that does not support their metabolic activity (Hubert et al. 2009). Thermospores are metabolically dormant states developed by some thermophilic bacteria having optimal growth temperatures between 40°C and 70°C. There is evidence that these heat-loving bacteria originate from the deep subsurface and are transported upward to the deep ocean via geological features of the oceanic crust including geofluid fluxes in high-temperature axial systems and natural hydrocarbon seeps (Gittins et al. 2022). Due to the ability of endospores to stay viable for thousands of years and resist a wide range of physicochemical stressors, they can disperse over long distances while remaining unaffected by changing factors such as selection, drift, or mutation (Gittins et al. 2022; Fig. 1). Consequently, these thermospores have the potential to challenge the distance-decay relationship and exhibit unique biogeographical patterns.This work quantifies endospores in sediment cores at and around hydrocarbon seeps using cores from deep-sea Scotian Slope sediments. Given the challenge of quantifying specific groups of endospores (e.g., thermophiles but not mesophiles), high-temperature germination assays that allow tracking of an exponential increase in signal as spores in marine sediment samples germinate and grow can be used. Distinct exponential increases can be attributed to different populations of germinated thermospores in the post-germination growth phase and are being monitored through measurements of sulfate reduction rates (using radiolabelled 35SO4), strain-specific quantitative PCR (qPCR), and fluorescence in-situ hybridization (FISH) (Rezende et al. 2017).  These measurements revealed growth dynamics enabling an estimation of the initial cell numbers using exponential functions. These approaches are being applied to samples obtained via push coring using a remotely operated vehicle at different distances from deep sea hydrocarbon seeps, to test for the presence of abundance gradients of different thermospores. Current results already show a difference in thermospore abundance between sites at different distances from the seep.Quantitative tracking of the dispersal of thermospores by oceanic currents in the deep sea provides an excellent opportunity to investigate their distribution and potential to colonize more remote habitats, improving the understanding of microbial biodiversity and biogeography on our planet. By investigating thermospores and their interactions with the geophysical features of the deep sea and deep subsurface, this study aims to challenge the canonical idea that speciation occurs with distance and presents new perspectives on the theme of microbial biogeography. The evidence supporting the subsurface origin of thermophilic endospores, along with the proposed model for their dispersal and distribution, will contribute toward improving an integrated understanding of ecology and geology and their intersection in the microbial realm. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Using AI to Fine Tune the Search for Life

    • Abstract: ARPHA Conference s 6: e108253
      DOI : 10.3897/aca.6.e108253
      Authors : Michael Phillips : Astrobiologists seek to find life beyond Earth. The “Holy Grail” of Astrobiology research is to discover evidence of a second genesis of life – an origin of life that was independent from life’s origin on Earth. No formal consensus on the possibility for a second genesis of life exists, and opinions about the probability range from near zero to near unity. An extra-terrestrial example of life would help answer this question and settle the quandary of whether life is common in the Universe or exceedingly rare. Quantifying the “ordinariness” of life has far reaching philosophical implications that could even inform us about the future of intelligent, technology-wielding life on Earth (Bostrom 2007).Life on Mars, one of our closest planetary neighbors, was considered a forgone conclusion as recently as the mid 20th century. What else besides an advanced civilization cultivating crops could have been responsible for the telescopically observed network of “canals” scarring its red surface' The “Advanced Martian Civilization” hypothesis had support from preeminent scientists, such as Giovanni Schiaparelli and Percival Lowell, but was relegated to the realm of pseudoscience when data from the Mariner spacecrafts in the 1970s failed to reveal any evidence for such civilizations. There is still no convincing evidence for life on Mars; however, several studies have at least raised one or two eyebrows (Mazur et al. 1978, McKay et al. 1996, Ruff and Farmer 2016).The Mariner missions ushered in the era of modern space exploration at Mars, and with it an earnest search for life. In 1976, shortly after the Mariner missions, the Viking I & II landers delivered “positive” results from their Labeled Release (LR) experiments. Oxidants in the martian regolith are the generally accepted explanation for these results, but some argue that life is the most parsimonious explanation for the Viking data (Levin and Straat 2016). We still do not know if life existed, or exists, on Mars, but Mars was once habitable for the forms of life that took root on early Earth and certain places on Mars likely remain habitable (Davila et al. 2010, Ehlmann et al. 2016). Its potential habitability and proximity to Earth have kept Mars centered in the crosshairs of Astrobiological research for decades. However, icy ocean worlds – Titan, Europa and Enceladus – have garnered increasing attention from the Astrobiology community (National Academies of Sciences and Medicine 2022), partially because any evidence for life on these worlds has a much higher chance of representing a second genesis whereas life on Mars could have potentially originated on Earth (or vice versa).The problems we face in the search for life on Mars today mirror those that confronted Schiaparelli and Lowell: we do not have data of sufficient quality to answer the question definitively. One major difference is that Schiaparelli and Lowell had their prior probability for the expectation of life on Mars set at what must have been a fairly high value. By contrast, decades of null results for evidence of life on Mars have tuned our expectations such that all abiogenic explanations for any piece of would-be-evidence-for-life must be rigorously rejected before biotic explanations can be considered (e.g., Ruff and Farmer (2016), Oehler and Etiope (2017)). Perhaps one day, incontrovertible evidence for life on Mars will be found that will open the floodgates for a reinterpretation of evidence that, at present, is too dubious to consider. Until then, a high bar is rightly set for the standard of evidence (Neveu et al. 2018). If evidence of life exists on Mars, it is apparent that it will not be easy to find.NASA developed a strategic exploration arc to hone in on the most likely places to find evidence of life on Mars. The strategy goes:Follow the water;Explore habitability;Seek signs of life.The “Follow the water” theme characterized missions from Mars Global Surveyor in 1996 to the Mars Atmospheric and Volatile EvolutioN orbiter in 2013. “Explore habitability” and “Seek signs of life” have overlapped, beginning in 2007 with the Phoenix lander and persisting to the present with the Perseverance rover at the Jezero Crater delta.Despite technological and philosophical advances in Astrobiology and the overarching principles guiding NASA missions, a coherent and standard strategy for quantifying the probability of finding life in an arbitrarily chosen environment does not exist. For example, when we land in a deltaic system on Mars we do not know, and in fact do not have a strategy for knowing, which specific outcrop, or rocks within in an outcrop, will have the highest probability of containing signs of past life. What would such a “signs of life search strategy” look like'In our recent paper (Warren-Rhodes et al. 2023), we propose that building a library of probability-of-life maps at nested spatial scales across many terrestrial-analog sites could be one way to address this question. Building probability maps relies on extensive microbial ecologic surveying, and can help us understand whether recognizable and predictable patterns characterize the distribution of terrestrial biosignatures. At our field site in Salar de Pajonales, Chile, we found that photosynthetic endolithic communities, the subject of our study, followed such a pattern. Their locations could be predicted using artificial intelligence (AI) models with an order of magnitude greater accuracy than a random search. Our study lays out a methodological framework for assessing a terrestrial analog site that combines geology, statistical ecology, and AI. The long-term vision is for the Astrobiology community to adopt and improve upon this strategy, and to build u...
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Differences in the Physicochemical Properties of Wildfire Generated
           Pyrogenic Carbon and Biochar

    • Abstract: ARPHA Conference s 6: e108249
      DOI : 10.3897/aca.6.e108249
      Authors : Katherine Snihur, Lingyi Tang, Kelly Rozanitis, Cody Lazowski, Daniels Kononovs, Daniela Gutierrez Rueda, Logan Swaren, Murray Gingras, Hongbo Zeng, Janice Kenney, Shannon Flynn, Kurt Konhauser, Daniel Alessi : Pyrogenic carbon (PyC) results from the pyrolysis of organic materials through thermal decomposition at high temperatures in low oxygen environments (I.B.I. 2012). The broad term includes many forms of thermochemically altered carbon, including charcoal, black carbon, soot, and biochar (Scott et al. 2014), and consists of a pyrolyzed carbon fraction as well as an inorganic ash or mineral fraction. PyC is produced naturally during forest fires, where it forms at potentially high temperatures (up to 1200 °C) for very short periods of time (seconds to minutes for temperatures>300 °C; Santin et al. 2016a). Wildfire derived PyC has been shown to be a significant component of the carbon cycle, with an estimated 32 Tg of PyC cycled through aquatic environments annually (Santin et al. 2016b). Man-made biochar is generated under controlled conditions via pyrolysis in furnaces at controlled temperatures and under anoxic conditions (Ahmad et al. 2014), typically up to 700 °C, for longer periods of time (up to ~6 hours). Several studies have investigated the surface chemistry of biochar and its ability to remove metals from aqueous solution (e.g., Alam et al. (2018a), Alam et al. (2018b)). However, PyC produced during natural pyrogenic activity such as wild fires, is produced under highly variable temperatures and atmospheric conditions, in the presence of numerous and variable microenvironments which are challenging to measure (Scott et al. 2014), and its surface chemistry and reactivity is not well understood. To fill this gap, we investigate the physicochemical properties including the proton and metal adsorption potential of wildfire generated PyC (WF-PyC) collected from 4 locations within a recent forest fire along the Western slope of Mount Hunter, near Golden, British Columbia. We explored the binding capacity of a model cation (species of Cd2+) under a range of environmentally relavent pH conditions (3-9) and then compared the findings to the adsorption potential of synthetically generated biochar produced from the same biomass. Fourier transform infrared (FTIR) and Raman spectroscopy was used to constrain the number and types of surface functional groups, and the coordination environment of Cd2+ ions bound to WF-PyC and biochar. Potentiometric titrations were performed and modelled to calculate the acidity constants associated with each site and the total reactive surface area of both biochar and WF-PyC. Our results demonstrate greater reactivity to Cd2+ associated with WF-PyC, not replicated in synthetic biochar of an equivalent biomass (Fig. 1). This both provides insight to the potential of WF-PyC to play a critical role as a vector for elemental transport in natural systems and also makes apparent the need to understand the pyrolysis conditions during forest fires to improve our understanding of its role in global metals transport and cycling. HTML XML PDF
      PubDate: Tue, 17 Oct 2023 17:15:15 +030
       
  • Assessing the Impact of Land Use and Land Cover on Water Quality: A Case
           Study of the Rákos Catchment in Hungary

    • Abstract: ARPHA Conference s 6: e108160
      DOI : 10.3897/aca.6.e108160
      Authors : Sahar Saeidi, Amir Mosallaei, Jalil Imani Harsini, János Grósz, István Waltner : Water quality maintenance is a crucial goal in today's society due to the increasing demand for water resulting from urbanization and population growth. Surface water quality can be impacted by various sources, particularly land uses in the surrounding basin. Land use and land cover (LULC) influence several processes in the water cycle, including interception, infiltration, evapotranspiration, runoff, and water storage. LULC changes can have significant effects on local water resources, including water quantity and quality.Hungary, despite its abundance of freshwater sources, faces the challenge of pollution in most of its water bodies. This study focuses on the Rákos catchment in Hungary to monitor and analyze its water quality and the effects of land use and land cover on it.The Rákos stream flows through different land use areas, including residential, industrial, agricultural, forested, and mixed zones, which can influence water quality conditions, especially due to anthropogenic sources. Additionally, the stream receives water from communal wastewater treatment facilities.The study area was divided into eight sampling points, considering changes in land use. Water samples were analyzed for temperature, pH, electrical conductivity, dissolved oxygen, nitrite, nitrate, ammonium, phosphate, chlorophyll-a, and total cyanobacteria. The monitoring campaign commenced in November 2019 with biweekly data collection, and this paper covers the data collected until November 2021.To understand the relationship between land use and water quality, land use and land cover information from the Corine Land Cover datasets for 2018 was incorporated. Pearson's correlation analysis was performed to assess the correlations between LULC types and water quality parameters based on monthly and seasonal averages.The findings from the Pearson's correlation analysis provide valuable insights into the relationships between land use types and water quality parameters in the study area. The significant correlations observed highlight the influence of specific land use categories on water quality, emphasizing the need for effective land management strategies to protect and improve water resources.Heterogeneous agricultural areas demonstrated positive correlations with nitrite, ammonium, and total dissolved solids, suggesting that agricultural activities in these areas may contribute to elevated levels of these water quality parameters. The use of fertilizers and pesticides in agricultural practices can lead to increased nutrient and sediment runoff, which may explain the observed positive correlations. These findings underscore the importance of implementing best management practices in agricultural areas to minimize potential negative impacts on water quality.Pasture areas, on the other hand, exhibited negative correlations with nitrate, ammonium, phosphate, and total dissolved solids, suggesting that pasture land may have a filtering or buffering effect on these water quality parameters. Vegetation in pasture areas can help intercept and absorb nutrients, reducing their transport to water bodies. However, the mixed effects observed in pasture land indicate that additional factors, such as grazing intensity and management practices, may also influence water quality outcomes in these areas. Further research is needed to better understand the mechanisms driving these correlations and to develop targeted management strategies for pasture lands.Industrial-commercial areas, urban fabric, forests, arable land, and pasture showed negative correlations with total dissolved solids but positive correlations with heterogeneous agricultural areas, dumpsites, and transitional woodland. These results suggest that non-agricultural land use types may contribute to lower levels of total dissolved solids in the water, potentially due to reduced sediment and pollutant runoff. However, these land use types also exhibited positive correlations with heterogeneous agricultural areas, dumpsites, and transitional woodland, indicating potential sources of pollution in these areas. Effective pollution control measures should be implemented in industrial, urban, and transitional areas to mitigate their impact on water quality.Interestingly, green urban areas showed a positive correlation with dissolved oxygen. This finding highlights the potential positive impact of urban green spaces on water quality. Vegetation in urban areas can enhance oxygenation through photosynthesis and provide habitat for diverse aquatic organisms. Urban planning initiatives that prioritize the incorporation of green spaces and the preservation of natural features can contribute to maintaining healthier water bodies within urban environments.It is important to note that the correlations observed in this study are based on monthly and seasonal averages, providing a general understanding of the relationships between land use types and water quality parameters. However, temporal variations, such as rainfall events and specific land use practices, may influence these relationships differently. Long-term monitoring and more detailed investigations are necessary to capture the full extent of these dynamics and to develop targeted management strategies for different land use categories.Overall, the results of the correlation analysis underscore the significance of considering land use types when assessing and managing water quality. This information can guide decision-making processes related to land use planning, agricultural practices, and urban development to ensure the preservation and improvement of water resources. Integrating these findings into water resource management strategies can contribute to the protection of aquatic ecosystems and the provision of cle...
      PubDate: Mon, 16 Oct 2023 09:46:59 +030
       
  • Response of Microbial Community Stability to Chemical Oxidation
           Remediation Process in a Petroleum Hydrocarbon Contaminated Groundwater
           Site

    • Abstract: ARPHA Conference s 6: e108148
      DOI : 10.3897/aca.6.e108148
      Authors : Wenjuan Jia, Shengmei Lv, Lirong Cheng, Yi Zhu, Aizhong Ding : The stability of the microbial community is a vital indicator of microbial ecosystems. However, the mechanism of microbial community stability during in situ chemical oxidation in petroleum-hydrocarbon-polluted groundwater is unclear. This study analyzed the biomass, diversity, co-occurrence network feature and negative cohesion of microbial community at different stages to identify the changes in microbial community stability under chemical oxidation. In addition, microbial module compositions and crucial functions were analyzed to further explore the reason for the change in community stability at the module level. Multiple regression analysis was conducted to explore the microbial module explanatory degree to microbial community stability changes. The results indicated that the microbial community stability was destroyed by chemical oxidation. The carbon source effect was the main reason in the early oxidation stage, while the oxidation stress effect was the main reason in the late oxidation stage. Most microbial modules were transformed from K-strategists to r-strategists, and modular keystones were transformed to stress-tolerant species in the oxidation stage. This study suggested that microbial clusters were essential indicators of the microbial community in petroleum hydrocarbon groundwater during the chemical oxidation period. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 14:34:17 +030
       
  • Comparing the microbial communities in and End-pit lake, active tailings
           ponds and freshwater bodies from the Athabasca oil sands region

    • Abstract: ARPHA Conference s 6: e108146
      DOI : 10.3897/aca.6.e108146
      Authors : Montserrat Villegas Torres, Peter Dunfield : The Athabasca oil sands region in northern Alberta is home to one of the largest bitumen deposits in the world. Oil sands are mostly recovered via surface mining and the oil extraction is achieved with hot caustic water and diluents, a process that produces liquid tailings waste (CEC 2020, Schramm et al. 2000). It is estimated that 1 m3 of bitumen produces around 4 m3 of tailings, which are contained in large tailings ponds (Mikula et al. 1996). End-pit lakes are a potential strategy to reclaim mining pits created by oil sands mining. They may be formed by filling a mined-out pit with tailings and then capping it with a layer of fresh water. With time, tailings undergo a dewatering process in which they become denser and release water to the cap water (Charette et al. 2012).Base Mine Lake (BML) is the first full-scale demonstration end-pit lake in the Canadian oil sands industry. This former tailings pond was initially capped in 2012 with a 5 m layer of freshwater to allow for consolidation of the tailings and the stimulation of aerobic microbial communities to biodegrade the organic pollutants. Since its establishment, BML has been extensively monitored to assess the improvement in water quality.The present research focused on determining how the eukaryotic and bacterial communities in BML compare to those in local freshwater bodies and active tailings ponds. Eleven reference sites, including freshwater reservoirs, natural lakes, and 9- to 14-year-old excavated pits filled with water, also known as borrow pits, were sampled along with 5 active tailings ponds and BML during the summer of 2022. Microbial communities were assessed via next-generation sequencing of PCR amplicons of the 16S rRNA gene for bacteria and the 18S rRNA gene for eukaryotes.Alpha-diversity analysis of the eukaryotic communities showed that BML has greater species richness and evenness than active tailings ponds, but lower than freshwater systems. The bacterial community in both BML and active tailings ponds is dominated by Proteobacteria, but the relative abundance of Actinobacteriota is similar between BML and freshwater. Beta-diversity analysis revealed that eukaryotic and bacterial communities in BML cluster distinctly from both the freshwater controls and active tailings ponds, however, the composition of the eukaryotic community shows some overlap with certain freshwater systems (Fig. 1). The results of this research suggest that, 10 years after its formation, the microbial communities in BML are intermediate between an active tailings pond and a freshwater lake. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 14:30:27 +030
       
  • Shotgun metagenomics from Monte Cristo cave (Brazil) reveals microbial
           metabolic potential related to iron and manganese biogeochemical
           cycles 

    • Abstract: ARPHA Conference s 6: e108139
      DOI : 10.3897/aca.6.e108139
      Authors : Maicon Araujo, Fernando Rossi, Amanda Bendia, Flavia Callefo, Evelyn Sanchez, Alessandra Vasconcelos, Douglas Galante, Fabio Rodrigues : Caves are among the most singular and understudied environments on Earth. Due to the harsh conditions observed in many caves, including scarcity of nutrients and low levels of light, these ecosystems are considered extreme environments (Gabriel and Northup 2012). Therefore, it may be worth paying special attention to the microbial communities existing in these unique systems. Previously, it has been suggested that the high levels of Manganese (Mn) and Iron (Fe) at Lechuguilla and Spider Caves in the United States may influence their microbial community structure in different ways (Northup et al. 2003, Carmichael and Bräuer 2015). In this context, caves are promising environments for investigating microbial functional capabilities in relation to these elements and the ecological interactions that allow these microbes to thrive. Monte Cristo cave (MCC) - in Diamantina, Brazil - was chosen for this study. The cave is located in a region known for historic mining activity and occurrences of Mn and Fe-rich rocks (Costa et al. 2003). With that in mind, our main goal is to investigate if within the microbial community of MCC there is evidence of taxa and genes associated with Fe and Mn metabolism. The samples were collected in 2018 from walls and saprolite deposits within MCC. Community DNA from three samples, P1b, P3 and P7, were independently sequenced using Illumina shotgun sequencing, and the data were analysed using conventional metagenomic pipelines and in-house python scripts. Taxonomic classification was assessed using Kraken2; Fe related genes with FeGenie; and Mn related genes were predicted using BlastP against a collection of manually curated Mn-oxidizing proteins. Environmental Mn and Fe concentrations were measured using ICP-OES. Our results suggest the presence of a microbial community potentially able to change Fe and Mn redox states. In sites P1b and P7, genes associated to Fe and Mn oxidation were identified, Fig. 1. Taxonomic evidence for these metabolisms includes the presence of the taxa Comamonadaceae and Hyphomicrobiaceae, both families that were previously reported to harbour species able to oxidize Mn and Fe (Spring and Kämpfer 2015, Carmichael and Bräuer 2015). Our analysis also assigned contigs to the archaeal phyla Crenarchaeota, Euryarchaeota and Thaumarchaeota, whose presence has been associated with oligotrophic caves where archaea play a role in primary production (Ortiz et al. 2013) (Fig. 2). Moreover, the phylum Euryarchaeota harbours members that use Fe or Mn as electron acceptors during methane oxidation (Ettwig et al. 2016). Our results therefore contribute to understanding how microbial communities of MCC may be playing a role in the biogeochemical cycles of Fe and Mn under the conditions imposed by the subterranean environment, which might reflect similar processes in other caves yet to be explored by a metagenomics approach. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 14:26:48 +030
       
  • The Impact of Phosphorus Level on Vivianite Precipitation during
           Microbial Reduction of Ferrihydrite

    • Abstract: ARPHA Conference s 6: e108138
      DOI : 10.3897/aca.6.e108138
      Authors : Xiaoqing Shao, Zach DiLoreto, Huan Liu, Xiancai Lu, Maria Dittrich : Iron minerals play a pervasive role in the cycling of phosphorus (P) within both terrestrial and aquatic environments. The behavior of P, especially in oxygen-depleted environments, is frequently regulated by changing redox conditions and the associated phase transformations of Fe (III) (hydr)oxides (Borch and Fendorf 2007). Although the stability of Fe (III) hydroxides under changing redox conditions is well established, the relationship between specific minerals and their influence on the mechanisms of P retention and release remain unclear. In particular, the minerals vivianite (Fe3(PO4)2·8H2O) and ferrihydrite (Fe2O3·0.5H2O) are of interest. Vivianite crystallization in sediments has attracted increasing attention as a major contributor to P retention during early diagenesis (Slomp et al. 2013) and ferrihydrite reduction has been linked to fluctuating P concentrations which can impact vivianite crystallization. Additionally, there exists strong biological controls on these minerals as the reduction of Fe (III) oxides by dissimilatory iron-reducing bacteria may result in the formation of a suite of Fe (II)-bearing secondary minerals (O’Loughlin et al. 2021). To better understand the biogeochemical mechanisms behind these interactions, we examined the effects of fluctuating P concentrations on the reduction of ferrihydrite by Shewanella putrefaciens CN32 and resulting vivianite formation.In this study, bio-reduction experiments were conducted under sterile conditions in serum bottles containing 80 mL of mineral medium, with 80 mM Fe (III) in the form of Ferrihydrite, and various P concentrations (0, 1 mM, and 10 mM). The bottles were placed on a roller drum (180 rpm) and incubated at 30 oC in the dark for 15 days. Dissolved Fe (II), P concentrations, pH, and optical density (OD) values throughout the experiments were also measured. Our results showed that during incubation, Shewanella putrefaciens CN32 accelerated Ferrihydrite reduction as the dissolved iron (Fe2+) concentration increased significantly when compared to other bacterial and ferrihydrite treatments, as well as the control treatment. Additionally, P in both the 1mM and 10mM treatments was depleted after 5 and 7 days, respectively, and resulted in crystalline precipitates. Scanning electron microscopy (SEM) analyses of precipitates showed well-formed and highly crystalline vivianite particles of up to 30 µm in length in high P level. Some crystalline precipitates were confirmed as vivianite through SEM and Raman spectroscopy matching a known vivianite reference (Taylor et al. 2008), but only within the 10mM P incubations. After 15 days of incubation the morphology of the vivianite changed from aggregates of lath-shaped crystals to acicular crystals (Fig. 1). Based on our results, fluctuating P concentrations do indeed have a pronounced effect on ferrihydrite reduction and thus vivianite formation. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 14:20:49 +030
       
  • Surface reactivity of the iron and manganese-oxidizing
           bacterium Leptothrix cholodnii SP-6

    • Abstract: ARPHA Conference s 6: e108135
      DOI : 10.3897/aca.6.e108135
      Authors : Maicon Araujo, Daniela Gutierrez Rueda, Yuhao Li, Janice Kenney, Daniel Alessi, Kurt Konhauser : Surfaces of prokaryotic cells play a significant role in the adsorption of metals from aqueous solution and the formation of authigenic minerals (Konhauser 2006). Although most studies focus on the cell wall, it is known that many bacteria synthesise an extracellular layer of polysaccharides and proteins, including what are known as sheaths. It has been shown that the cyanobacterium Calothrix sp. produces as sheath which is neutrally charged at circumneutral pH values, and it was hypothesized that such a sheath might allow the cyanobacterium to survive in geothermal settings with high silicification rates (Phoenix et al. 2002). Specifically, the dominance of hydroxyl sites on Calothrix’s sheath surface facilitates hydrogen bonding with aqueous silica species, inducing the precipitation of amorphous silica on the sheath and thus protecting the underlying cell (Phoenix et al. 2002). Leptothrix cholodnii is a sheathed, iron and manganese-oxidizing bacterium that frequently inhabits minerals seeps, where Fe2+ and Mn2+ discharge into oxygenated surface waters (Spring et al. 1996). As a result, the sheath becomes encrusted with Fe(III) and Mn(IV) oxyhydroxides while the underlying cells are protected from mineralization (Emerson and Ghiorse 1992, Emerson et al. 2010). However, unlike Calothrix, Leptothrix’s sheath composition suggests that it might behave differently at circumneutral pH (Emerson and Ghiorse 1993). To investigate the surface reactivity of Leptothrix's sheath and cell wall we analyzed isolated sheaths, sheathless cells, and intact filaments of L. cholodnii SP-6. We studied these components using potentiometric titration, zeta-potential, Cd-adsorption, and Fourier transform infrared (FTIR) spectroscopy to elucidate changes in surface charge between the cell wall and sheath. For the isolated sheaths and intact filaments, titration data were fit using a two-site protonation model, resulting in the following pKa values: 6.05 (±0.29) and 9.34 (±0.11); and 7.77 (±0.17) and 10.50 (±0.20), respectively. For the sheathless cells, the best fit was obtained by using a three-site protonation model, resulting in the following pKa values: 5.40 (±0.59), 8.11 (±1.64) and 10.73 (±0.45). Total proton-active site concentrations were lower in isolated sheaths compared to intact filaments. Additionally, at circumneutral pH, net negative charge was lower for sheathless cells compared to intact filaments and isolated sheaths (Fig. 1). This information agrees with the Cd adsorption behaviour found for the three materials (Fig. 2). Thus, our preliminary results suggest that Leptothrix’s sheath is less reactive than the intact filaments at circumneutral pH, leading us to hypothesize that the outermost layer would sequester relatively lower amounts of cations, including Mn2+, from solution and potentially would protect the underlaying cell from deleterious mineralization. In addition to that, the less reactive sheath’s surface would also contribute to cell attachment, which is important for a species commonly found in streams (Phoenix et al. 2002, Emerson et al. 2010).  HTML XML PDF
      PubDate: Fri, 13 Oct 2023 14:15:11 +030
       
  • In situ sensor-based monitoring strategies for biogeochemical reactions in
           mine tailings environments

    • Abstract: ARPHA Conference s 6: e108130
      DOI : 10.3897/aca.6.e108130
      Authors : Eric Nakoh, Allison Enright : Natural resource extraction and ore processing have significant environmental impacts, such as the generation of wastewater, waste rock and tailings. These waste products are often detrimental to ecosystems, and negatively impact surface and groundwater bodies, often necessitating remediation treatments and long-term management of sites by operators, or, where operators have abandoned a contaminated site, by regulators and government agencies. Such cleanup and monitoring efforts regularly continue for decades after a site is closed.Monitoring efforts usually serve two purposes: characterizing the long-term changes at a site once extraction and processing activities have ceased and evaluating the effectiveness of applied remediation treatments. Monitoring activities are usually mandated in the site’s operating license and usually include frequent field sampling of surface water, groundwater, and soil or sediment, as well as ecological studies describing floral and faunal abundances. These samples are then analyzed to quantify the mobility and phase of contaminants (i.e., toxic heavy metals, hydrocarbons), fundamental water quality parameters (i.e., pH, TDS, alkalinity), and the makeup and function of the microbial community (i.e., culturing, microcosms, ‘omics). The need for skilled workers and constant on-site personnel presence means that environmental monitoring is a high- cost activity for site operators and is a significant financial burden for government and regulatory agencies tasked with managing abandoned legacy mine sites.Over the last decade, rapid developments in platforms for deploying remote scientific instrumentation, lower-cost environmental sensors, and data transmission from remote locations have brought about a renewal of interest in sensor-based environmental monitoring strategies. These approaches offer several advantages, such as lower cost, near real-time data access, and lower exposure risk to toxic and hazardous materials.Here, we will present data collected from a suite of electrochemical sensors deployed in situ at a closed, managed mine site to monitor the effectiveness of remediation treatments in real-time. These results provide proof-of-concept for the effectiveness of sensor-based monitoring technology as part of safe, effective long-term remediation and management strategies.  HTML XML PDF
      PubDate: Fri, 13 Oct 2023 14:10:22 +030
       
  • Ancient organic matter in black shales as a carbon source for deep
           subsurface life

    • Abstract: ARPHA Conference s 6: e108123
      DOI : 10.3897/aca.6.e108123
      Authors : Lotta Purkamo, Riikka Kietäväinen, Lukas Kohl, Maija Nuppunen-Puputti, Ellen Lalk, Shuhei Ono, Malin Bomberg : The fluids at black schist-rich bedrock in the Fennoscandian shield have been shown to carry extensive methane (Kietäväinen and Purkamo 2015, Kietäväinen et al. 2017). The sources of methane, abiotic, microbial, thermogenic, or their mixtures, are not well understood (Etiope and Sherwood Lollar 2013, Douglas et al. 2017). While previous field and laboratory studies have concentrated on oxic degradation of relatively low metamorphic grade black shales (e.g., Matlakowska et al. 2012, Petsch et al. 2005), our goal was to explore the genetic potential of microbial communities in naturally anoxic, oligotrophic and moderately saline bedrock fluids in contact with high-metamorphic grade organic carbon containing black schist. We tested if the microbial metabolisms could explain the extensive methane detected from the fluids at black schist -rich bedrock in the Fennoscandian shield. We aimed to determine the difference between abiotic and biotic methane formation in Palaeoproteorozoic bedrock using novel methane isotopologue measurements and evaluate the ability of natural microbial communities to use black schists as a carbon source in enrichment cultures and compare these to the previously reported cultures. Two study sites, namely the Outokumpu Deep Scientific Drill Hole at depth of 1470 m and Juuka/Miihkali116 overflowing deep drill hole in Finland, were selected for comprehensive geochemical and microbiological sampling. The sampling campaign involved collecting samples for methane isotopologues, intrinsic microbial community, and fluid for inoculation of laboratory microcosms. Ground and sterilized black shists of two different maturities obtained from Finnish bedrock, 13C-labeled graphite, cellulose, acetate and CO2 were used as different carbon sources for intrinsic deep subsurface fluids, and these microcosms were incubated for 8-20 months. Subsequently, the gas phase of the microcosms was analyzed for CH4, CO2, N2O, O2, and N2 concentrations, as well as isotopic ratios of carbon in CH4 and CO2. Bacterial, archaeal and fungal communities were characterized using phylogenetic marker gene amplicon sequencing from both the intrinsic deep subsurface fluids and the microcosms after the incubation period.The results of this study indicate that methane in these sites is likely formed abiotically, as evidenced by the isotopologue data and the absence of methanogenic archaea in the microbial communities. Moreover, the gas data and isotope ratios obtained from the microcosms suggest that graphitic carbon is predominantly transformed into carbon dioxide rather than methane, further supporting the isotopologue data. Throughout the incubation period, the microbial communities within the microcosms exhibited dynamic changes. Specific microbial groups known for their capacity to utilize complex or recalcitrant organic matter and xenobiotics were observed, indicative of the challenging, oligotrophic and nutrient-deficient subsurface environments. Moreover, microbes regarded as keystone species in the deep terrestrial biosphere were observed.This study sheds light on the processes driving methane formation and the associated microbial communities in ancient black shales. The findings suggest a predominantly abiotic origin for methane in these Finnish Palaeoproterozoic bedrock formations, highlighting the potential for alternative mechanisms of microbial carbon assimilation and the importance of microbial communities in carbon cycling in subsurface ecosystems. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 14:06:25 +030
       
  • Exploring Biomarker Signatures in Glaciovolcanic Environments:
           Implications for the Search for Life on Mars

    • Abstract: ARPHA Conference s 6: e108122
      DOI : 10.3897/aca.6.e108122
      Authors : Erin Gibbons, Richard Leveille, Greg Slater, Kim Berlo : Glaciovolcanic systems, where hydrothermal heat interacts with ice, offer favorable conditions for life by providing liquid water, nutrients, and physicochemical gradients (Cousins and Crawford 2011). Despite significant climate change, evidence for glaciovolcanism is widespread through Mars’ history. Such sites may have offered refugia for life after Mars lost much of its surface water, representing some of the most recent habitable areas and promising sites to recover biomarkers. We examined a terrestrial glaciovolcanic site to study the indigenous biological community structure, the supporting physicochemical parameters, and the distribution of biomarkers within the geologic context. The insights will help refine Mars exploration of analogous sites.Method: We studied a partially subglacial hydrothermal area at the summit of the active Kverkfjöll volcano, Iceland. The heated ground has created a large ice-damned meltwater lake with shoreline hot springs, thermal streams, and mud pots of variable activity. We collected water and sediment samples aseptically across the breadth of features, including the lake (surface & depth). Samples were kept at -4°C. Environmental parameters were measured at each sample site. Sediment samples were split for mineralogical and organic analysis. Mineralogy was measured by X-ray Diffraction. Organic samples were freeze-dried and extracted with a Bligh & Dyer method (Bligh and Dyer 1959). Extracts were divided into hydrocarbons, neutral lipids, glycolipids, and phospholipid fatty acids (PLFA) with hexane, dichloromethane, acetone, and methanol. Gas Chromatography/Mass Spectrometry was used to analyze hydrocarbons and PLFA as fatty acid methyl esters.Results:Environmental: Fluids ranged from acidic to alkaline (pH 3-9), low to high temperature (8-87°C), and severely dysoxic to oxic (0.5-5 mg/L dissolved O). Mineralogy comprised a dioctahedral swelling clay, heulandite, and minor quartz, anatase, and pyrite. The assemblage suggests argillic-grade alteration at 100-140°C (Fulignati 2020), confirming that the glaciovolcanic conditions were within theoretical boundaries for life (
      PubDate: Fri, 13 Oct 2023 13:37:12 +030
       
  • Seasonal variation of gross ecosystem productivity of periphyton in three
           post-mining lakes in the Czech Republic, Europe

    • Abstract: ARPHA Conference s 6: e108115
      DOI : 10.3897/aca.6.e108115
      Authors : Kateřina Čapková, Klára Řeháková, Tomáš Bešta, Petr Čapek, Jan Mareš, Eliška Konopáčová : We investigated the seasonal variation of gross ecosystem productivity (GEP) of periphyton biomass in three post-mining lakes in the Czech Republic. These lakes were established as part of recultivation efforts after coal mining activities and resulted in a unique series of anthropogenic oligotrophic lakes of gradual successional age. Periphyton is ubiquitous in aquatic habitats and performs numerous environmental functions such as nutrient cycling and self-purifying of aquatic ecosystems. Well-developed periphyton mat can be formed within a few weeks, so it can quickly become the dominant of littoral zone of newly established lakes. In studied post-mining lakes, the highly developed periphytic community covers the littoral zone of each lake to the depth of 2m (Bešta et al. 2022, Konopáčová et al. 2023) Fig. 1.We aimed to shed some new light on the processes controlling the dynamics of primary productivity in oligotrophic lakes. The accurate estimation of primary productivity is crucial for understanding the functioning of aquatic ecosystems, as primary productivity serves as the primary source of autochthonous carbon in these systems. In addition to phytoplankton, periphyton can significantly contribute to primary productivity in littoral zones, known for their high productivity and biodiversity. Conducting in situ measurements provides the most accurate means of inferring the metabolic activity of primary producers in littoral zones.We conducted detailed seasonal in-situ periphyton gross primary production (GPP) measurements in three post-mining lakes with different successional ages (Čapková et al. 2022).  GPP and NPP of periphytic biomass were determined using direct in-situ measurement of O2 fluxes. O2 production and consumption were measured over 5 hours of in-situ light and dark gas-tight glass bottle incubation. Bottles were filled with the lake water from the corresponding depth, and a similar amount of periphytic biomass was enclosed Fig. 2. We used the Fibox3 fibre-optic oxygen meter coupled with a PSt3 oxygen sensor (PreSens, Regensburg, DE) to measure changes in O2 concentration. The O2 fluxes were normalized to periphytic biomass in each bottle (measured as total organic carbon). Data were corrected for O2 concentration changes in dark and light gas-tight bottles containing lake water without periphytic communities.This setup enabled us to monitor online oxygen flux, therefore, insights into metabolic activities. The primary productivity was measured in real-time, allowing us to capture the quantitative effect of various environmental drivers on periphyton productivity, i.e. phosphorus concentration and light intensity, as they are known to play significant roles in primary productivity.We showed that the primary production of periphyton mats exhibited seasonal variations, with higher productivity observed in spring compared to other seasons. This observation could be attributed to the occurrence of winter/spring upwelling events and vertical mixing, which resupply nutrients from the deeper strata. Furthermore, the physiological activity of periphyton was strongly influenced by the seasonal changes in light intensity, temperature, and nutrient concentration.We provided the first insight into the seasonal variation of primary productivity of the periphyton assemblage dominating the littoral zone of newly established post-mining lakes. We stress the importance of periphyton in aquatic ecosystems, particularly in anthropogenic oligotrophic lakes. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 13:25:22 +030
       
  • Microbial activities along a 20 million-year-old pristine oil reservoir

    • Abstract: ARPHA Conference s 6: e108098
      DOI : 10.3897/aca.6.e108098
      Authors : Lisa Voskuhl, Hannah Möhlen, Christian Schlautmann, Sadjad Mohammadian, Ann-Christin Severmann, Johannes Koch, John Köhne, Erling Rykkelid, Joachim Rinna, Rainer Meckenstock : Studies on oil reservoir microbiology typically take samples from producing reservoirs and sample fluids that have been pumped to the surface. This comes with problems since producing oil reservoirs are affected by production processes leading to changes in environmental conditions and the natural microbiome. Hence, pumped samples do not display an unaltered picture of the spatial distribution and composition of the microorganisms in the reservoir.We took 13 samples from a freshly drilled sediment core of a pristine, heavily biodegraded oil reservoir in the North Sea. Core samples originated from above, within, and below the reservoir.16S rRNA gene amplicon sequencing of the microbiome revealed distinct differences between sediments and formation water, indicating that studies on microbiomes from formation water alone are not necessarily representative for the microbial processes in an oil reservoir. Fluorescence microscopy showed that microorganisms live in small microcolonies on the sediment surface. CT-scanning with image analysis visualized the water phase distribution inside the reservoir sediments and clearly indicated water-filled voids that might be habitable for microorganisms, enlarging the surface for potential biodegradation. Employing microcosm experiments and reverse isotope labelling, we were able to determine the first degradation rates measured from cores above, within, and below a reservoir ranging from no activity up to 1 mM CO2/(gsediment x year), Results indicate significant degradation potential from autochthonous microorganisms in the reservoir above the water-contact-zone.Evading the general issues of produced oil samples for studying microbiomes results in a more realistic picture of an oil reservoir unaffected by production artefacts. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 13:19:51 +030
       
  • Nitrate-Reducing Fe(II)-Oxidizing microorganisms: linking Fe, C and N
           Cycles in subsurface environments

    • Abstract: ARPHA Conference s 6: e108089
      DOI : 10.3897/aca.6.e108089
      Authors : Cristina Escudero Parada, Andreas Kappler : The discovery of the Nitrate-Reducing Fe(II)-Oxidizing (NRFeOx) microbial metabolism, which couples the oxidation of Fe(II) to the reduction of nitrate (NO3-) using organic matter or carbon dioxide (CO2) as carbon source, was a major milestone in microbial ecology (Straub et al. 1996). NRFeOx microorganisms play an essential role on a global scale in three of the most important biogeochemical cycles: iron (Fe), carbon (C) and nitrogen (N) (Kappler et al. 2021, Huang et al. 2021). In addition, these organisms participate in the mobilization or stabilization of organic carbon, as well as in CO2 fixation, thus contributing to the reduction of atmospheric CO2 (Kappler et al. 2021). Finally, the activity of these microorganisms is key to remove the pollutant NO3- from aquifers, which is one of the major worldwide environmental issues since many environments exceed the maximum regulatory concentration (50 mg L-1) (Kazakis et al. 2020 ).A plethora of NRFeOx microorganisms have been described in the last decades. However, most of these microorganisms have been reclassified as chemodenitrifiers. That is to say, Fe(II) is not enzymatically oxidized but indirectly by the reactive nitrogen species produced during denitrification (Fig. 1 ). In fact, only in three cultures so far, named KS, BP and AG, has the presence of true NRFeOx metabolism been unequivocally demonstrated (Straub et al. 1996, Huang et al. 2021b, Jakus et al. 2021b).Cultures KS, BP and AG have been studied thoroughly in the past years, analyzing the rate and mechanism by which these communities carry out autotrophic NRFeOx. Different omics studies have revealed that cultures KS, BP and AG consist of a mixture of bacterial species, which collaborate in order to grow under autotrophic NRFeOx conditions. Each culture is dominated by a novel candidate species of the genus Ferrigenium (Huang et al. 2022) capable of fixing CO2 and oxidizing Fe(II), but which requires flanking species to complete denitrification (Huang et al. 2021b, He et al. 2016, Huang et al. 2021a).Interestingly, these communities not only carry out NRFeOx using dissolved Fe(II) as energy source (Straub et al. 1996, Huang et al. 2021b, Jakus et al. 2021b), but they can also oxidize Fe(II) minerals, the main form in which Fe(II) can be found in the Earth's crust (Huang et al. 2021). In fact, Fe(II)-bearing minerals are thought to be the main drivers of NO3- reduction in subterranean environments (Huang et al. 2021), which has additional ecological consequences. NRFeOx microorganisms can trigger the turnover of the Fe(II)-bearing minerals, resulting in the mobilization of mineral structural elements such as S, P, C or contaminant heavy metals and the precipitation of Fe(III) minerals at circumneutral pH (Weber et al. 2001, Jakus et al. 2021a).Here, we will present a review of the insights learned from the three NRFeOx autotrophic cultures and discuss their ecological role, their importance in biogeochemical cycles, and their potential biotechnological applications. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 13:13:07 +030
       
  • Enzymatic Degradation of PET plastic  

    • Abstract: ARPHA Conference s 6: e108084
      DOI : 10.3897/aca.6.e108084
      Authors : Erin Griffiths, John Honek, Stephanie Slowinski, Fereidoun Rezanezhad, Philippe Van Cappellen : Polyethylene terephthalate (PET) plastic is one of the most commonly used polymers worldwide and found in high rates as environmental waste. Previous studies have shown that the degradation of plastics using commercial grade enzymes is possible and highly effective in lab settings. However, the effectiveness and rates of enzymatic plastic degradation at environmentally relevant conditions is less known. In this study, we set up a series of sacrificial incubation experiments using a commercial enzyme, Humicola insolens cutinase (HiC), to examine the effect of various environmental variables, including temperature, pH, and salinity, on the hydrolytic degradation of PET. This was performed by measuring the mass loss at different time points during degradation, dissolved organic carbon produced in solution by PET hydrolysis, the Fourier transform infrared (FTIR) spectra of the PET surfaces, and scanning electron microscope (SEM) images of the PET surfaces. The results indicate that the degradation rate is 15-times faster at 55 °C than at 40 °C at pH 8 (1.93 mg day-1 versus 0.13 mg day-1), giving an initial estimate for the activation energy of PET hydrolysis of 2.2 kJ mol-1. In the 55 °C experiment which ran for 10 days, there was a noticeable decrease in the plastic strength and deformation of the plastic after 1 week of degradation. In the 40 °C experiment (duration 16 weeks), FTIR spectral changes were observed as early as week 6, with peaks of interest at 2,970 cm-1, 2,350 cm-1, 1,240 cm-1 , and between 1,300-1,000 cm-1. Ongoing experiments with pH and salinity will provide insight into their effects on the PET degradation rate. Altogether, these results will provide a comprehensive framework for predicting PET degradation rates, and by extension, other plastics that are degraded by hydrolysis, at environmentally relevant pH, temperature, and salinity conditions. In addition, these results provide insight into the effect of degradation on the chemical spectra of plastics and microplastics.  HTML XML PDF
      PubDate: Fri, 13 Oct 2023 13:11:14 +030
       
  • Friend or Foe' Microbial impact of Calcigel bentonite on metal materials
           used for nuclear waste repository

    • Abstract: ARPHA Conference s 6: e108081
      DOI : 10.3897/aca.6.e108081
      Authors : Sean Ting-Shyang Wei, Vladyslav Sushko, Nicole Matschiavelli, Sindy Kluge, Andrea Cherkouk : Multi-barrier concept is a favorable option to store high-level nuclear waste (HLW) in a deep geological repository. Bentonites are processed clay materials that are considered as a geotechnical barrier for metal containers storing HLW. To understand the impact of indigenous microorganisms from bentonites on these metal materials, anaerobic microcosms incubating Calcigel bentonite, synthetic Opalinus clay (OPA) porewater, lactate (one of the organic acids in natural OPA porewater) or H2 gas (product from anaerobic metal corrosion) with or without cast iron metal plates were conducted for up to 9 months in triplicates for each condition and time point (sampling every 3 months). The amplicon sequencing targeting V4 region of 16S rRNA genes showed that microbial communities of raw Calcigel bentonites mainly comprised phyla Acidobacteria, Actinobacteria, Chloroflexi, Firmicutes, Proteobacteria and Methylomirabilota. In the microcosms with lactate, enrichment of Bacillaceae (Firmicutes) and uncultured MB-A2-108 (Actinobacteriota) were observed; whereas in the presence of both lactate and cast iron, genera of Firmicutes, namely Desulfotomaculum, Desulfitobacterium and Desulfallas-Sporotomaculum, were highly enriched (relative abundance ranged from 60% to 95%) associating with large decrease in sulfate and lactate concentration. These bacteria appeared to be driven by H2 gas generated from metal corrosion. Moreover, SEM-EDX analyses showed that the metal surface was corroded and covered by a carbonate passivation layer. In this layer, FeS appeared to be formed, further suggesting the influence on cast iron corrosion and formation of secondary minerals induced by sulfate-reducing bacteria.On the other hand, we supplied N2 gas mixed with H2 and CO2 (80:10:10) to stimulate growth of H2-oxidizing sulfate reducers. GC analyses showed that in the microcosms without cast iron, the content of H2 gas in the headspace decreased accompanying with decrease in sulfate concentration (measured via IC). However, in the microcosms with cast iron we noted large accumulation of H2 gas (~ 5 times more than initial value) and greater decrease in sulfate concentration. Similarly, surface corrosion was visible by SEM-EDX, and thre carbonate passivation layer with possible FeS precipitates was formed on the metal surface but in a shorter timeframe (3 months). Hence, we speculated that certain autotrophic H2-oxidizing sulfate reducers also corroded cast iron metal, and their taxonomy and mechanisms will be identified using metagenomic approaches.Altogether we concluded that microbial communities in Calcigel bentonites lead to microbially induced corrosion for cast iron under certain conditions, yet interestingly, the formation of passivation layer enhances the resistance for further metal corrosion. The actual impact of indigenous microorganisms in different bentonites, either disadvantageous or beneficial, on metal containers for HLW requires comprehensive investigations. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 13:05:42 +030
       
  • Electron Acceptor Addition to Stimulate Anaerobic Methanotrophy in Oil
           Sands End Pit Lakes 

    • Abstract: ARPHA Conference s 6: e108078
      DOI : 10.3897/aca.6.e108078
      Authors : Hanna Davidson, Peter Dunfield : A major question for the Alberta oilsands extraction industry is how to return tailings ponds to their original ecosystem functions at the end of their lifespan. This question is one of the most pressing in the oil industry, and while many potential solutions are being trialed, none are without issue. One solution is the creation of end pit lakes (EPLs), formed by filling a mine pit or tailings pond with fluid tailings and covering this with a freshwater cap. Over time, tailings settle to the bottom of the lake and become sequestered. As of 2018, there were 23 plans to pursue EPLs in Albertan oilsands mining operations (COSIA 2021), so research in oilsands reclamation via EPLs is essential.Alberta has only one full-scale EPL formed using tailings, Base Mine Lake (BML). It has been under reclamation since 2011. Although BML water quality is gradually improving over time, one persistent problem is the production of methane bubbles from the entrenched hydrocarbons. Ebullition of these bubbles carries contaminants into the water column. The potential to limit methane production biologically by stimulating methanotroph metabolism, is therefore of interest. Methanotrophs are microbes that consume methane. These methanotrophs can be aerobic, in the water column, or anaerobic below the sediment interface, where oxygen is depleted. Anaerobic oxidizers of methane, or AOM, are of particular interest due to methane only being produced in anaerobic conditions. However, AOM are not well-studied and there are many gaps in our knowledge about them. Base Mine Lake presents an important opportunity to document the presence of AOM in oilsands ecosystems, and identify if AOM can remove methane before it enters the water column.Methane is probably not the limiting factor for AOM in BML- instead, the electron acceptors used in the absence of oxygen are scarce. If microbiological methane removal were to increase after supplementing electron acceptors such as nitrate, sulfate, or iron, then this could be applied to the reclamation of artificial end pit lake systems. Our research aims to illustrate if AOM are present in BML, and if we can stimulate their metabolism via electron acceptor amendment.We performed amplicon and metagenomic sequencing across 5 sediment cores from BML. These cores penetrate over two meters below the water-sediment interface, up to 14 meters below the water’s surface. We designed anaerobic, 13C-isotope-spiked incubations for this sediment to track if any CH4 to CO2 conversion was underway. By tagging methane molecules with 13C, we are able to follow the biogeochemical transformations and demonstrate if any 13CH4 is converted to 13CO2, which would indicate methanotrophic activity. Additionally, microbes who take up 13C produce heavier DNA, possibly allowing us to identify the DNA of the players at work. Additionally, Illumina sequencing was done on all incubations to compare how electron acceptor addition prompted community shifts.In the incubation experiments, 13CO2 is being produced in several core samples incubated without O2. This finding indicates that methanotrophs are, in some capacity, active in anoxic conditions. When comparing different amendments of electron acceptors, there did appear to be a significant amount (p = 0.027) of 13CO2 produced in the sulfate-added 13CH4 treatment (Fig. 1). Other amendments had encouraging results, but were not statistically significant. Ongoing trials will provide more illuminating results via larger sample sizes, which will be completed by the end of the summer. Next we will characterize communities in the post-incubation sediment, using both amplicon sequencing and DNA stable isotope probing. This will suggest not only the identity of the organisms at play, but will also illuminate which electron acceptors were most beneficial to which groups. This analysis is complex and underway.Overall, the study of methanotrophy in artificial ecosystems with high emissions is an area of great interest, due to the high potential for amendment and improvement of the ecosystems using methanotrophs, as well as the ongoing discovery on AOM in artificial ecosystems. Oilsands end pit lakes are of interest, as an issue of cultural and political emphasis. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:59:57 +030
       
  • Soil Salinization May Trigger Mercury Mobilisation from Contaminated Soils
           and Sediment

    • Abstract: ARPHA Conference s 6: e108043
      DOI : 10.3897/aca.6.e108043
      Authors : Marco Contin, Stefano Tomat, Elisa Pellegrini, Maria De Nobili, Mara Mauri, Milena Horvat : Mercury (Hg) contamination of soils is a concerning issue worldwide due to its high toxicity and risk to human health. Source of contamination, chemical form and environmental conditions affect its mobility and hence bioavailability. Contaminated coastal soils, could potentially become hotspots of Hg re-mobilisation, because of simultaneous flooding and salinization caused by sea level rise as a consequence of climate change.The aim of our work was to assess changes in Hg solubility in soils and sediments, with different type of Hg contamination, after exposure to salt and flood stresses.A soil contaminated by mining activity (mainly cinnabar-Hg) and a sediment heavily contaminated by a chlor-alkali plant (mainly elemental Hg) were collected from North-East Italy. Mercury speciation was performed either by Thermal Desorption (TD) or by a Sequential Extraction Procedure (SEP) to quantify operationally defined binding forms (soluble, exchangeable, bound to Mn or Fe oxides, bound to organic matter, non-cinnabar and cinnabar Hg forms).A bench top simulation with 0 to 32.8 g l-1 salt solution was carried out in microcosms filled with contaminated soil or sediment, to characterize flood effects on Hg mobility. Soils were kept submerged for different inundation periods (1, 7 and 30 days). After the flooding treatment, a rain event was simulated using artificial rain water. Solubilised Hg of each flood and each leaching treatment was measured by ICP-MS.Thermal desorption showed the presence of two main forms of Hg: organic bound Hg and HgS. The cinnabar-Hg peak was largely prevalent in the mine-contaminated soil, whereas the organic-bound-Hg peak was prevalent in the chlor-alkali contaminated sediment. This difference was confirmed by the liquid SEP speciation.Hg mobility increased with increasing salinity and flooding time. The effect of salt concentration was more pronounced for longer flooding periods. After 1 day of inundation, the amount of solubilised Hg was negligible, but after 7 days flooding Hg levels in the highest saline solution reached up to 0.9 and 9.3 µg Hg L-1 in the soil and in the sediment simulations, respectively. The mobility of Hg increased substantially after 30 days, and was about 22 times in the soil (19.8 µg Hg L-1) and 10 times in the sediment (89.8 µg Hg L-1) compared to the background level.Our results show a potential risk of Hg re-mobilization from contaminated coastal soils and sediments as consequence of sea level rise and their consequent salinization. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:55:17 +030
       
  • Genetic evidence that multiple cytochrome nanowires are necessary for
           Fe(III) oxide reduction in Geobacter sulfurreducens

    • Abstract: ARPHA Conference s 6: e108028
      DOI : 10.3897/aca.6.e108028
      Authors : Madeline Ammend, Chi Chan, Daniel Bond : Geobacter sulfurreducens is a dissimilatory metal-reducing microorganism capable of utilizing insoluble acceptors via extracellular electron transfer. While a large number of multiheme c-type cytochromes expressed by G. sulfurreducens are implicated in linking its cytoplasmic respiratory chain to materials beyond its outer membrane, whether these proteins have specific roles in reduction or recognition of particular metals is unknown. Recently, structures of three extracellular conductive c-type cytochrome filaments, often referred to as nanowires, were reported. Comprised of either OmcS, OmcE, or OmcZ, these nanowires are long polymers of protein subunits with a core of closely spaced hemes, with no similarity in sequence, fold, glycosylation, subunit size, or diameter. We utilized a markerless deletion approach to construct single, double, and triple-deletion strains in an isogenic background to investigate possible roles of OmcS, OmcE, and OmcZ. When soluble Fe(III) or the organic acceptor fumarate were electron acceptors, no defects were observed in any mutant. When freshly precipitated Fe(III) oxide was tested as an electron acceptor, mutants lacking omcE were strongly affected, reducing Fe(III) approximately half as fast. No other single mutant (∆omcS or ∆omcZ) showed a defect. Double mutants containing only omcE (∆omcSZ) also showed a defect, suggesting other proteins could be required in addition to OmcE. The double mutant containing only omcZ (∆omcSE) also showed a partial defect, while double mutants containing only omcS (∆omcEZ) were completely unable to reduce Fe(III) oxide. The triple (∆omcESZ) mutant was also unable to reduce Fe(III) oxides. Taken together, this indicates that genes for two separate nanowires are necessary to completely reduce this form of Fe(III) oxide. This is the first evidence that omcZ, which has only been implicated in electron transfer to electrodes, could also be needed for metal reduction. With the recent discovery of two completely unrelated mutltiheme cytochrome nanowires in thermophilic Archaea, different conductive filaments with different substrate specificities may have repeatedly evolved to facilitate extracellular respiration. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:50:26 +030
       
  • Emergence of the 2.1 Ga Francevillian biota was preceded by unprecedented
           hydrothermally driven seawater eutrophication

    • Abstract: ARPHA Conference s 6: e108014
      DOI : 10.3897/aca.6.e108014
      Authors : Ernest Chi Fru, Jérémie Aubineau, Olabode Bankole, Mohamed Ghnahalla, Landry Soh Tamehe, Abderrazak El Albani : Recently, two independent studies suggest that the emergence of putative fossilized macro-eukaryotes in the Paleoproterozoic Francevillian Basin, ~2.1 billion years ago, may be related to a rise in seawater Zn bioavailability. This explanation is reliant on their extraordinary high Zn content and association with light Zn isotopes characteristic of eukaryotic enrichment. However, the trigger and origin of rising seawater Zn supply to the basin remains unknown. This study unravels a transient episode of intense submarine hydrothermal activity that triggered the weathering of a nutrient-rich oceanic crust reservoir, related to the collision of the Congo-São Francisco cratons during the Eburnean-Transamazonian orogeny, as the source of abundant seawater dissolved Zn, together with a suite of essential trace metals and phosphate to the continental margin waters. Surprisingly, the initiation of hydrothermal weathering coincided with the rapid onset of a rare Paleoproterozoic seawater eutrophication event. This transition is marked by basin-wide redox stratification, high sediment loading with organic carbon (Corg) and nitrogen, elevated C/N ratios, a steep negative Corg and positive bulk N isotope excursion, positive Ce anomalies, and low Mn/Fe ratios. Importantly, the transient eutrophication event ended with a reversal to lower seawater phosphate levels that coincided with  rapid seawater ventilation and the appearance of macrofossil bearing sediments in Franceville. We suggest that these unexpected, localized conditions, set the stage for the emergence of the Francevillian biota. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:48:36 +030
       
  • Co-transport of Microplastics and a surrogate for Human Enteric Viruses in
           a saturated column packed with Quartz Sand

    • Abstract: ARPHA Conference s 6: e108005
      DOI : 10.3897/aca.6.e108005
      Authors : Ahmad Ameen, Birgit Bromberger, Patrick Mester, Alexander Kirschner, Alfred Blaschke, Margaret Stevenson : Groundwater can be contaminated with infective human enteric viruses from various sources, such as wastewater treatment plant discharge, landfills, septic tanks, agricultural practices, and artificial groundwater recharge. Anthropogenic pollutants, such as microplastics, may exhibit an affinity to transport biocolloids (bacteria, viruses) further and reduce their degradation rates in the natural environment. Human enteric viruses (poliovirus, hepatitis A, rotavirus, and adenovirus) can adsorb to the abiotic surface of microplastics and are simultaneously present in wastewater discharge. These newly formed clumps of pathogens and microplastics could penetrate deeper into soils as vectors for preferential flow and threaten groundwater systems, triggering a higher risk for drinking water and possibly followed by a disease outbreak. The mechanisms behind the adsorption of human enteric viruses on microplastic surfaces and their potential role in prolonging virus survival and promoting environmental transport remain unclear. This study aims to explore the possibility of co-transport of microplastics and human enteric viruses in saturated porous media, using PRD1 bacteriophage as a surrogate. PRD1 bacteriophages have been widely used as surrogates of rotavirus because they share many fundamental properties and features.Column experiments were performed using quartz sand (soil grain size: 0.60 - 1.30 mm) as a porous media in a 30 cm long and 7 cm diameter column. The column experiments were conducted by maintaining Darcy velocity of 2.65 m/day. Three different influent solution scenarios were considered in the experiments: PRD1 mixed with microplastics, PRD1 alone, and microplastics alone. The enumeration of PRD1 in the effluent solution was performed using quantitative polymerase chain reaction (qPCR) as well as the culture method, in order to differentiate between infective and inactive virus transport. Microplastics were quantified using Solid-Phase Cytometry (SPC). Results were analyzed by calculating the collision and sticking efficiencies of the microplastics and PRD1 using the classical colloid filtration theory and Hydrus 1D modeling tool.There was no evidence of interference or inhibition of microplastics on the performance of qPCR and DNA extraction in the methodological setup. Additionally, the efficacy of qPCR and DNA extraction methods did not yield significantly different results across any of the influent solution conditions. Preliminary results suggest that the presence of microplastics enhanced the transport of PRD1, which led to reduced attachment of PRD1 in the porous media. The concentration of infective phages showed a delayed sharp increase, indicating that there may be a sorption mechanism that delays their breakthrough. It is possible that a portion of the active phages possess a higher sticking efficiency and that population heterogeneity contributes to this phenomenon. A comprehensive understanding of the processes that govern virus transport with globally distributed microplastics is crucial for protecting public health. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:45:40 +030
       
  • The Undiscovered Biosynthetic Potential of the Greenland Ice Sheet
           Microbiome

    • Abstract: ARPHA Conference s 6: e108004
      DOI : 10.3897/aca.6.e108004
      Authors : Ate Jaarsma, Katie Sipes, Athanasios Zervas, Francisco Jiménez, Andrea Smith, Liessel Svendsen, Lea Ellegaard-Jensen, Mariane Thøgersen, Peter Stougaard, Liane Benning, Martyn Tranter, Alexandre Anesio : The Greenland Ice Sheet is a biome primarily driven by microbial activity. Despite the harsh conditions, such as cold temperatures, low nutrient levels, high UV radiation in summer, and long dark winters, various niches can be found on the ice sheet that can support organisms capable of withstanding these challenges. During the summer, eukaryotic glacier ice algae grow in large quantities on the ice surface, accompanied by a community of bacteria, fungi, and viruses. Additionally, cryoconite holes and snow serve as habitats with their own distinct microbial communities. Nevertheless, the microbiome of supraglacial habitats remains poorly studied, leading to a lack of representative genomes from these environments. In this study, we conducted a comprehensive investigation of the supraglacial microbiome using both culturing-dependent and -independent methods. We compared genomes obtained through metagenomic sequencing (133 high-quality metagenome-assembled genomes or MAGs) and whole genome sequencing (73 bacterial isolates) to the metagenome assemblies to determine their abundance within the total environmental DNA. Interestingly, the isolates obtained in this study were not dominant taxa in their respective habitats, unlike the MAGs.Under-investigated extremophiles, such as those inhabiting the Greenland Ice Sheet, may offer an untapped reservoir of undiscovered chemical diversity. We cataloged the biosynthetic potential of these organisms by examining the presence of biosynthetic gene clusters (BGCs) in the obtained genomes. To accomplish this, we utilized tools like the Antibiotics and Secondary Metabolites Analysis Shell (AntiSMASH) and the Biosynthetic Gene Similarity Clustering and Prospecting Engine (BiG-SCAPE) to mine these genomes and subsequently analyze the resulting predicted BGCs. We identified a total of 849 BGCs, which were organized into 411 gene cluster families (GCFs). Notably, the MAGs and isolate genomes exhibited distinct pools of biosynthetic diversity, with only 5 GCFs shared between the two groups. The cryoconite genomes yielded the most unique GCFs. Furthermore, we found evidence for the capacity of these microbes to produce antimicrobials, carotenoids, and osmoprotectants. However, many of the obtained BGCs could not be matched to similar, previously described BGCs, highlighting the vastness of the undescribed biosynthetic potential present in microbes from the Greenland Ice Sheet. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:40:38 +030
       
  • Survival Strategies of High GC-Content Microorganisms in Oligotrophic Deep
           Groundwater

    • Abstract: ARPHA Conference s 6: e107970
      DOI : 10.3897/aca.6.e107970
      Authors : Maryam Rezaei Somee, Carolina González-Rosales, Stephanie Turner, Stefan Bertilsson, Mark Dopson, Maliheh Mehrshad : Deep groundwaters are among the most energy and nutrient-limited ecosystems on the planet. The limited resources are mainly due to the absence of photosynthesis-driven primary production (Kadnikov et al. 2020). These ecosystems do however host phylogenetically diverse and metabolically active microorganisms from all domains of life plus viruses (Holmfeldt et al. 2021, Mehrshad et al. 2021). In this study, we used a large metagenomic dataset generated over the last eight years from the Äspö Hard Rock Laboratory (Äspö HRL) in Sweden and drill holes in Olkiluoto Island, Finland. This dataset, termed the “Fennoscandian Shield Genomic Dataset” (FSGD), contains metagenome-assembled genomes (MAGs) and single-cell amplified genomes (SAGs). Previous studies on this dataset have shown that reciprocal symbiotic partnerships and efficiency of energy metabolism define the core microbiome of these deep groundwaters (Mehrshad et al. 2021). Studies on different marine and freshwater ecosystems show that oligotrophic environments host streamlined genomes with lower GC content. However, it is not known how the low carbon and energy availability in deep groundwaters affect the microbial community regarding their genome size and GC content. To address this, we used the FSDG to study the distribution of genome size and GC content among bacterial and archaeal genomes in Fennoscandian Shield deep groundwaters. We further disentangled the prevalent metabolic strategies in these genomes that is being used to support their carbon and nitrogen demands for replication and survival.A total of 1990 MAGs/SAGs with a completeness of ≥50% and
      PubDate: Fri, 13 Oct 2023 12:38:25 +030
       
  • Different manure management methods impact on nitrogen use efficiency -
           comparison of four dairy farms in Hokkaido Japan

    • Abstract: ARPHA Conference s 6: e107926
      DOI : 10.3897/aca.6.e107926
      Authors : Haruka Sato, Yoshitaka Uchida : To maintain balanced biogeochemical cycles, minimizing the nutrient wastes from agricultural activities is critically important. Agricultural activities such as dairy farming produce large amounts of nitrogen waste in natural ecosystems. The increased nitrogen waste from dairy farming potentially causes environmental damage, such as eutrophication and greenhouse gas emissions. To accurately assess these changes in nitrogen wastes from dairy farming systems, measurements of variable parameters related to the nitrogen cycle (e.g., nitrogen gas emissions, nitrogen loss to water ecosystems), but these are time-consuming. Instead, calculating farm gate-level nitrogen surplus and nitrogen use efficiency (NUE) is a practical method to estimate the nitrogen waste from dairy farming systems. The nitrogen surplus and NUE are calculated based on the difference and ratio between nitrogen input (such as fertilizer and feed) and nitrogen output (such as milk and meat) on each farm. The data needed to calculate the nitrogen input and output can be obtained by interviewing farmers. Thus it is often easier than directly measuring nitrogen cycle parameters. In addition, it is known that excess nitrogen wastes are often related to improper manure management (i.e., manure is not efficiently collected and returned to the farm as nutrients) on dairy farms. In the dairy farming regions in Japan, particularly in Hokkaido, improper manure management can occur because of the short grass growing season and long winter, which means a large amount of manure has to be stored for an extended period. However, few previous studies quantitatively linked manure management and NUE in Japan. Thus, a study was needed to assess the link between manure management styles and the farm gate-level nitrogen surplus and NUE. Using the data from several Japanese dairy farms, we clarified the following:Whether nitrogen losses during manure management can be a controlling factor for the NUE of the whole farm or not.Other management options  necessary to keep the NUE within an appropriate range.Interviews were conducted with four small-scale (34–42 milked cows per farm) grazing dairy farmers in Central and Eastern Hokkaido to estimate their nitrogen balance and calculate NUE. The data for the year 2022 was used to calculate the NUE and nitrogen surplus. The data included all the fertilizer and feed information as nitrogen inputs, while milk and meat production as nitrogen outputs. Also, the basic information about the farm (e.g., area and stocking rates) was collected. Then, the total nitrogen and inorganic nitrogen (ammonium-form nitrogen and nitrate-form nitrogen) in excreta samples at various stages from a barn to pre-application in each farm were measured to assess the amount of nitrogen loss and nitrogen forms (e.g., ammonium- and nitrate-nitrogen) during the manure management period. These data were used to calculate manure utilization efficiency (the ratio of applied manure-derived nitrogen to nitrogen in excreta). Many Japanese dairy farmers store the manure for extensive periods (sometimes over a few years) to produce matured compost. Thus it is essential to know the changes in nitrogen status during the storage period. Also, manure processing systems were recorded, such as solid-liquid separation and aeration methods of the slurry. As a result, surplus nitrogen and NUE ranged from 37.6 to 140 kg/ha/year and 25.6 to 56.3%, respectively. Manure utilization efficiency ranged from 0 to 38.6%. Nitrogen surplus tended to be lower when the manure utilization efficiency was higher. The variability of the manure utilization efficiency was due to the farmers not applying the whole amount of the stored manure and the potential loss of nitrogen during the storage. The proportion of manure-derived nitrogen to total nitrogen fertilizer (the sum of manure-nitrogen, nitrogen chemical fertilizer, and other organic nitrogen fertilizer) ranged from 0 to 100%. It was positively correlated (P
      PubDate: Fri, 13 Oct 2023 12:36:29 +030
       
  • Hydrogen-Driven Microbial Redox Reactions in Deep Geosystems

    • Abstract: ARPHA Conference s 6: e107916
      DOI : 10.3897/aca.6.e107916
      Authors : Martin Krüger, Anja Dohrmann : In the subsurface, biotic and abiotic processes can generate and consume hydrogen. Hydrogen has a low reduction potential and is thus a highly energetic electron donor when involved in sulfate, carbon dioxide or ferric iron reduction. Although known as important drivers for the deep biosphere, the contributions of different processes to hydrogen turnover in different geosystems still are not well understood. In context with the ongoing transformation to renewable energy resources, underground H2 storage (UHS) in deep porous or salt cavern systems came into focus. In situ microbial and geochemical reactions that consume H2 are highly relevant topics in deep biosphere research, and also are still a major uncertainty during UHS.Consequently, we studied the potential microbial hydrogen oxidation rates – combined with the possible production of metabolic products like H2S, acetic acid or CH4 - in formation fluids from natural gas fields and salt caverns, thereby considering the importance of in situ pressure and temperature conditions, fluid chemistry and mineral composition. In addition, more defined experiments were conducted with selected pure cultures representing important metabolic groups of deep biosphere microorganisms.Several original formation fluids showed immediate H2 consumption. Microorganisms oxidized hydrogen at relevant in situ pressure conditions (up to 100 bar) and tolerated dynamically changing pressure and temperature conditions. The microbial hydrogen oxidation rate was strongly dependent on H2 partial pressures and the availability of e.g., sulfate as a terminal electron acceptor. High-throughput sequencing of 16S rRNA gene amplicons indicated hydrogen oxidation by sulfate reducing bacteria to be the presumed process in the studied porous rock reservoir fluids. In addition, hydrogen turnover by methanogenic and acetogenic as well as iron-reducing microorganisms was investigated. Also, the importance of biotic reactions in relation to abiotic hydrogen turnover processes at mineral surfaces will be discussed. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:31:49 +030
       
  • Application of geomicrobial techniques to constrain mechanisms of arsenic
           mobilisation in anoxic aquifers

    • Abstract: ARPHA Conference s 6: e107756
      DOI : 10.3897/aca.6.e107756
      Authors : Teto Seitshiro, Naji Bassil, Oliver Moore, Jonathan Lloyd : Geogenic arsenic contamination of groundwater in South and South-East Asia poses a significant human health threat, causing a range of health conditions including but not limited to cardio-vascular disease, cancer and skin lesions (Argos et al. 2010, Pienkowska et al. 2021). Arsenic contamination also hosts a range of dire socioeconomic implications for the affected areas. A variety of mechanisms for arsenic release in anoxic aquifers have been proposed, however, the most widely accepted mechanism is the microbial reduction of As-bearing Fe(III) (oxyhydr)oxide minerals coupled with the oxidation of organic carbon (Glodowska et al. 2020, Gnanaprakasam et al. 2017). Recent research has implicated methane as a possible carbon source in the reduction of Fe(III) (oxyhydr)oxide minerals and the subsequent release of arsenic into the groundwater (Gnanaprakasam et al. 2017, Pienkowska et al. 2021). The research suggests that methanotrophs have the ability to drive anaerobic oxidation of methane, AOM, coupled to Fe(III) (oxyhydr)oxide reduction. In this study, we aim to provide unequivocal evidence for the occurrence of AOM coupled to Fe(III) (oxyhydr)oxide as well to further explore the exact mechanism(s) involved which is yet to be characterised. Here we present an overview of our work so far. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:17:43 +030
       
  • Disentangling carcass size and climate effects on soil biogeochemistry
           during decomposition

    • Abstract: ARPHA Conference s 6: e107627
      DOI : 10.3897/aca.6.e107627
      Authors : Sarah Keenan, Colette McAndrew, Scott Beeler : When an animal dies the decomposition of its carcass releases multiple compounds that become available to soil microbiota altering soil biogeochemistry. This zone of affected substrate is characterized by significant changes to numerous soil biogeochemical parameters including pH, conductivity, microbial respiration rates, dissolved organic carbon (DOC), C/N ratios, carbon and nitrogen stable isotopes (δ13C and δ15N), and major/trace elemental concentrations. Although the effects of animal decomposition on these parameters have been recorded for various organisms and in a variety of ecosystems several knowledge gaps remain, including:the effect of carcass size; anddecomposition effects in prairie ecosystems (i.e., semi-arid climates).Here, we investigate how soil biogeochemical parameters are affected by the decomposition of a horse carcass (~660 kg) in a prairie ecosystem in comparison to beavers (~18 kg) in a temperate forest. Three parameters were identified as significantly influenced by carcass size: conductivity, DOC, and microbial respiration rate. Average soil conductivity underneath the horse carcass was three to fifteen times higher than control soils and reached a maximum at 1114 ADD, while maximum soil conductivity values were observed after 160 ADD in beaver-associated soils. Maximum DOC concentrations were observed after 160 ADD in beaver-associated soil (67 ± 40 mg C gdw-1) and after 1114 ADD in horse-associated soil (326 ± 115 mg C gdw-1). Microbial respirations rates were both greater in horse-associated soil and longer-lasting compared to beaver-associated soil. Respiration rates were greatest in two of the three horse-associated soils after 1114 ADD (~733 µg CO2-C gdw-1 day-1), which significantly differs compared to beaver-associated soils (300 ± 90 µg CO2-C gdw-1 day-1 at 160 ADD). Taken together, these results demonstrate that larger carcasses result in a greater release of decomposition products, including C, and greater stimulation of soil heterotrophic communities. Other measured biogeochemical indicators of decay suggest a mixed influence due to carcass size and climate, notably δ15N values of the soil, and major element concentrations. Climate was revealed to be more important in controlling changes to pH and gravimetric moisture than carcass size, with baseline soil conditions and type playing critical roles. Additionally, in semi-arid regions such as western South Dakota, the role of wet-dry cycles on carcasses undergoing decomposition may help to explain the pulses observed with C concentrations and C cycling. This study provides the first direct comparison of soil biogeochemistry associated with the decomposition of two different sized taxa decayed in two different climates. Attempting to normalize climate data using ADD was found to be an imperfect system that does not account for all climate variables affecting decomposition. Unravelling patterns in decomposition can better help to constrain nutrient cycling in modern and ancient ecosystems. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 12:08:07 +030
       
  • Investigating Microbial Triggers of Nitrous Oxide Emissions in
           Agriculturally Influenced Aquatic Ecosystems

    • Abstract: ARPHA Conference s 6: e107604
      DOI : 10.3897/aca.6.e107604
      Authors : C Crundwell, Lori Phillips, Chris Weisener : The agricultural sector in Canada is responsible for approximately 9% of greenhouse gas (GHG) emissions in Canada, accounting for 54 MT of carbon dioxide (CO2), as well as 31% of methane (CH4) and 75% of national nitrous oxide (N2O) emissions in 2021 (Environment and Climate Change Canada 2021). However, these estimates do not include the indirect GHG emissions that occur in agriculturally impacted waterways. Ontario is home to over 45 000 kilometers of agricultural drainage ditches, with tile drains directly connecting terrestrial and aquatic environments. Microbial biogeochemical cycles in the causeways experience fluxes of nutrients leading to hotspots for GHG at the sediment-water interfaces. Along with fluxes of nutrients, the causeways are regularly disturbed by anthropogenic effects (e.g., dredging, removal of vegetative buffers) and increasing frequency of storm events. Previous studies have used static chambers to evaluate GHG emissions from aquatic systems (Mu et al. 2022, Xiao et al. 2016). However, this approach can be time consuming and labour intensive and is impractical in aquatic systems due potential extensive underestimation of fluxes from diffusion. To resolve driving factors contributing to GHG in these systems a detailed study investigating the activity of the microbial community is warranted. In this study we hypothesize microbial activity within the sediment will correlate with N2O emissions. To test the response of the microbial community a combination of molecular approaches (i.e., qPCR and Ion torrent) targeting archaeal and bacterial nitrifiers and denitrifies was used. These functional responses were evaluated with respect to N2O emissions, which were measured in the field at the time of sampling using Unisense N2O probes. In this study, N2O sensor response was calibrated to a functional gene index for rapid risk assessment of GHG hotspots. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 10:39:19 +030
       
  • Anaerobic Isoprene-Degrading Microorganisms and their Impact on Microbial
           Methane Dynamics in Deep-Sea Carbonates and Eucalyptus-Leaf Sediments

    • Abstract: ARPHA Conference s 6: e107618
      DOI : 10.3897/aca.6.e107618
      Authors : Samikshya Giri, Nancy Prouty, Sabrina Beckmann : Isoprene, a highly abundant biogenic volatile organic compound, has emerged as a crucial yet overlooked factor in addressing climate change. Despite its widespread production in all forms of life, comprehensive data on its global biogeochemical cycle remain scarce. Isoprene's reactivity in the atmosphere influences methane concentrations, with detrimental implications for climate, air quality, and health. Conversely, methane is abundant in marine and terrestrial subsurface environments, where deep-sea carbonates serve as hotspots for microorganisms performing anaerobic methane oxidation—an essential process in long-term methane storage and removal from the marine carbon cycle. Recent studies by Beckmann et al. (2020), Prouty et al. (2020) have shed light on novel metabolic pathways utilized by microbial communities in carbonates for methane oxidation. Similarly, in terrestrial environments, eucalyptus trees, as the highest emitters of isoprene, may harbor microorganisms capable of metabolizing isoprene alongside methane-oxidation and formation in eukalyptus leaf detritus. However, little is known about the fate of isoprene and the potential microbial communities involved in its metabolism within deep-sea carbonates and eucalyptus-leaf sediments, potentially impacting methane metabolism. Our study aims to unravel the anaerobic pathways of microbial isoprene degradation and investigate the effects of isoprene abundance and degradation on microbial methane production and oxidation. We detected anaerobic isoprene-degradation in deep-sea carbonates and terrestrial eukalyptus-leave sediments, where methane oxidation and methane formation was pronounced. Surprisingly, the presence of isoprene inhibited mcirobial methane-oxidation as well as methane-formation, suggesting an substantial impact of the presence of isoprene on methane cycling and storage. We are currently characterizing and isolating the microorganisms involved in the isoprene and methane metabolism in these enrichment cultures. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 10:39:16 +030
       
  • Subsurface Transport of Sulfidated Nano Zero Valent Iron and In Situ
           Biogeochemical Transformation of Chlorinated Solvents: A Field Study

    • Abstract: ARPHA Conference s 6: e107556
      DOI : 10.3897/aca.6.e107556
      Authors : Jingzhi Liang, Hardiljeet Boparai, Line Lomheim, Ariel Nunez Garcia, Elizabeth Edwards, Denis O'Carroll, Brent Sleep : In situ chemical reduction of chlorinated volatile organic compounds (cVOCs) by nano zero-valent iron (nZVI) has been widely applied in the past 20 years, but with limited effectiveness for bare nZVI due to rapid particle settling, short lifespan, and low reactivity. Stabilization and sulfidation of nZVI have improved its mobility and longevity, increased reactivity towards cVOCs, and reduced toxicity to microbes (Nunez Garcia et al. 2021).In the first-ever CMC-S-nZVI field trial, nZVI sulfidated by dithionite (S-nZVI) and stabilized by carboxymethyl cellulose (CMC) was injected into the subsurface of a site contaminated with a wide range of cVOCs. Multi-level wells were installed to monitor the transport of the CMC-S-nZVI suspension and its remedial performance for two years. Short-term (0-17 days) monitoring demonstrated a good transport of the suspension in the down- and up-gradient wells, in terms of total iron, boron, and sulfides which were major constituents of CMC-S-nZVI. Changes in concentrations of parent compounds, intermediates, and ethene showed effective dechlorination of high-chlorinated VOCs such as tetrachloroethene (PCE) and carbon tetrachloride (Nunez Garcia et al. 2020a, Nunez Garcia et al. 2020b). Long-term (157-729 days) performance was evaluated through temporal analyses of microbial communities, total iron, boron, and cVOCs in groundwater samples. Microbial populations, including organohalide-respiring bacteria, increased by>1 order of magnitude; with Geobacter being the most abundant. This long-term enrichment can be attributed to the low toxicity of CMC-S-nZVI and biostimulation by CMC and perhaps Fe3+. Non-metric multidimensional scaling analysis was carried out on microbial data grouped by depth range and proximity to the injection well. At locations that clearly received CMC-S-nZVI, there was a significant shift in microbial communities that was sustained for the long term.Iron concentrations increased substantially in long-term samples while boron concentrations decreased, suggesting that this iron did not come from CMC-S-nZVI. Microbial dissolution of iron minerals might have contributed to the increased iron content (Jones et al. 2006). Excess dithionite in CMC-S-nZVI would also have reductively dissolved native iron from the soil, as successfully demonstrated in the in situ redox manipulation (ISRM) technology wherein subsurface Fe3+ in soil was reduced to Fe2+ for long-term remedial purposes (Vermeul et al. 2000).Long-term changes in concentrations of lesser-chlorinated VOCs and hydrocarbons suggest that PCE was degraded via both the microbially-mediated sequential hydrogenolysis as well as the abiotic β-elimination. The intermediate vinyl chloride (VC) surprisingly did not accumulate in the current study, in contrast to the significant VC accumulation in a previous un-sulfidated CMC-nZVI trial at the same location (Kocur et al. 2016). Excess dithionite injected in this study might have avoided VC accumulation, as previously reported for ISRM treatment of a cVOCs-contaminated site (Vermeul et al. 2000). Additionally, the identified bacterial populations might have utilized sulfur species (from dithionite decomposition) and iron to form iron sulfides, which could dechlorinate cVOCs via in situ biogeochemical transformation (Kennedy et al. 2006).In summary, this study has demonstrated the long-term efficiency of CMC-S-nZVI for cVOCs removal through a combination of abiotic, biotic, and biostimulatory processes in the subsurface.  HTML XML PDF
      PubDate: Fri, 13 Oct 2023 10:35:04 +030
       
  • Biodegradation of Benzene Under Microaerobic Conditions: a Groundwater
           Microcosm Experiment Combined with a Multiomics Approach and DNA Stable
           Isotope Probing

    • Abstract: ARPHA Conference s 6: e107378
      DOI : 10.3897/aca.6.e107378
      Authors : Andras Tancsics, Anna Bedics, André Soares, Balázs Kriszt : Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX) are the most common contaminants of the groundwater and can easily contaminate drinking water sources due to their relatively high water solubility. Among these compounds, benzene is known to have carcinogenic properties and is considered to be persistent under anoxic conditions. Although deep knowledge was acquired both on the aerobic and anaerobic degradation of benzene in the past three decades, the diversity of those bacteria which are able to degrade it under microaerobic conditions, is still unknown. To come over this limitation aerobic and microaerobic benzene-degrading microcosms were established using groundwater sediment of a BTEX-contaminated site and the evolved bacterial communities were investigated through a polyphasic approach including multiomics analysis and DNA stable isotope probing. The obtained results shed light on the fact that the aerobic and microaerobic benzene-degrading bacterial communities were distinctly different. In the aerobic microcosms members of the genus Pseudomonas overwhelmingly dominated the bacterial communities by showing even 40-50% abundance. In contrast, under microaerobic conditions members of the genera Azovibrio and Malikia dominated the communities, while the abundance of Pseudomonas drastically decreased compared to that of was observable in the aerobic microcosms. Results obtained by the analysis of microcosms spiked with 13C6-benzene confirmed these observations. In heavy DNA fractions obtained from the aerobic microcosms the enrichment of Pseudomonas and Rhizobiaceae-related 16S rRNA gene fragments was observable. At the same time, labelled DNA from the microaerobic microcosms contained mostly Azovibrio and Malikia-related sequences, while the abundance of Pseudomonas 16S rRNA gene sequences was below 2%. Besides, by using metagenomic dataset of a previous microaerobic experiment we managed to reconstruct an Azovibrio genome, in which a complete meta-cleavage pathway for the aerobic degradation of aromatic hydrocarbons was identified. Overall, it can be concluded that under microaerobic conditions members of Comamonadaceae and Rhodocyclaceae can be the key benzene degraders in contaminated subsurface environments. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 10:29:07 +030
       
  • Beyond Phosphorus: Salinization as a driver of eutrophication symptoms in
           North American lakes

    • Abstract: ARPHA Conference s 6: e107318
      DOI : 10.3897/aca.6.e107318
      Authors : Jovana Radosavljevic, Stephanie Slowinski, Fereidoun Rezanezhad, Chris Parsons, Philippe Van Cappellen : The acceleration of global urbanization continues to fuel concerns surrounding water quality impairments in urban lakes, particularly eutrophication. Eutrophication of freshwater environments is generally assumed to be driven by increased anthropogenic phosphorus (P) supplies which can alleviate limitations on primary production. Salinization is also recognized as a stressor on urban freshwater quality, particularly in cold temperate climate regions where salts are applied to road surfaces as de-icing agents. While the ecological damages caused by P enrichment and salinization to freshwaters are both well established, thus far, their impacts on water quality have only been considered independently. Although improvements to the management of urban stormwater and wastewater have decreased P inputs to freshwater systems in recent decades, many lakes worldwide remain eutrophic, as indicated by declining dissolved oxygen (DO) concentrations and rising dissolved inorganic P (DIP) concentrations in the hypolimnion. Our previous study of an urban freshwater lake in Ontario, Canada, showed that persistent eutrophication symptoms are linked to salinization associated with impervious land cover expansion, rather than increased external P loading. In this research, we present a multiple decade of water chemistry data analyses for several other urban lakes in Ontario, Wisconsin, and Minnesota to determine how increased lake salinization rates intersect with water temperature and morphometry to alter water column stratification, thus, increasing eutrophication symptoms. Our trend analysis shows progressive salinization (observed through significant increases in chloride or electrical conductivity) of all the lakes investigated. Calculations of lakes mixing indices over time show that, on average, lake stratification is becoming more stable with increased salinity playing a crucial role in enhancing lake stratification. Overall, salinity is becoming a stronger regulator of water density than temperature in the cold temperate urban freshwater lakes of North America. The increasing salinity trends are accompanied by increasing hypolimnion hypoxia and increasing DIP to total P (TP) ratios in all lakes, thereby demonstrating the mechanistic link between salinization and internal P loading. Rising salinity intensifies water column stratification, in turn, reducing the oxygenation of the hypolimnion and enhancing internal P loading from the sediments. These results highlight that stricter management of de-icing salt application rates should be considered to control lake eutrophication symptoms in cold climate regions. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 10:24:56 +030
       
  • Microbial Impacts on Colloid-Radionuclide Interactions

    • Abstract: ARPHA Conference s 6: e106921
      DOI : 10.3897/aca.6.e106921
      Authors : Chloe Morgan, Natalie Byrd, Callum Robinson, Laura Lopez-Odriozola, Sean Woodall, Samuel Shaw, Louise Natrajan, Katherine Morris, Jonathan Lloyd : Microorganisms can play an important role on the behaviour of colloids in natural and engineered environments, which in turn can control the mobility of associated metals and radionuclides. This is especially true in the nuclear fuel cycle, where radionuclides (including uranium) can interact with a broad range of inorganic colloids. This is relevant to the legacy spent nuclear fuel ponds at Sellafield, which house a diverse inventory of waste from the early Magnox reactors. These reactors used uranium metal as a fuel encased in a magnesium non-oxide cladding. Corrosion of the cladding results in the release of radionuclides, primarily uranium, and the formation of brucite (Mg(OH)2) phases which are present both in the corroded Magnox sludge at the base of the pond and suspended in the water column as colloids (Gregson et al. 2011). These brucite colloids have the potential to mobilise insoluble phases providing an important pathway for radionuclide migration. The spent nuclear fuel ponds are maintained at high pH to minimise corrosion of the cladding, however significant corrosion has still occurred.Despite the seemingly inhospitable conditions in spent nuclear fuel ponds, numerous studies have found microorganisms capable of surviving in spent nuclear fuel ponds (Dekker et al. 2014, Foster et al. 2020, Ruiz-Lopez et al. 2020). Previous work has demonstrated increased abiotic sorption of strontium to brucite in the presence of organic matter derived from Pseudanabaena catenata (Ashworth et al. 2018), which dominates algal blooms in the ponds. In this study we focus on uranium interactions with colloidal brucite in the presence of microbes adapted to high pH environments under conditions relevant to the spent nuclear fuel ponds at Sellafield. HTML XML PDF
      PubDate: Fri, 13 Oct 2023 10:20:11 +030
       
  • Phosphorus and Lake Eutrophication: Recent Findings and Emerging
           Challenges

    • Abstract: ARPHA Conference s 6: e107183
      DOI : 10.3897/aca.6.e107183
      Authors : Philippe Van Cappellen : This presentation reviews some recent and ongoing research on phosphorus (P) cycling in a variety of lake systems. Phosphorus is an essential nutrient element, and its anthropogenic enrichment is generally considered to be the main driver of cultural eutrophication of freshwater lakes, which, in the worst case, leads to the occurrence of harmful algal blooms, the intensification of hypoxia and the die-off of aquatic life. The research presented shows that excess external P loading causes the accumulation of reactive chemical P forms in the bottom sediments of lakes (Update #1). The slow release of this reactive legacy P back to the water column can significantly delay a lake’s recovery following the reduction of external P loading (Update #2). Land use changes accompanying agricultural intensification and urbanization generally increase P emissions, but the implementation of agricultural and stormwater best management practices can effectively mitigate external P loads to receiving lakes (Update #3). However, additional stressors, including climate change and salinization, magnify in-lake P mobilization pathways and, hence, increase the risks of lake (re-)eutrophication (Update #4). HTML XML PDF
      PubDate: Fri, 13 Oct 2023 10:16:19 +030
       
  • Unveiling the ecological significance of algal mats and meadows: Insights
           into phosphorus cycling and primary production of benthic algae in
           post-mining lakes

    • Abstract: ARPHA Conference s 6: e107027
      DOI : 10.3897/aca.6.e107027
      Authors : Klara Rehakova, Kateřina Čapková, Eliška Konopáčová, Jiří Nedoma, Jan Mareš, Tomáš Bešta, Lenka Štenclová, Andreja Kust : Post-mining lakes are anthropogenic water bodies increasing globally due to mining suppression and recultivation. These lakes have ecological and socioeconomic significance, providing freshwater sources, wildlife habitats, and recreation potential. However, research on primary producers in these lakes is limited, with most studies focusing on phytoplankton while neglecting algal mats and meadows. If developed in high biomass, algal mats and macroalgal meadows play a crucial role in aquatic ecosystems. They contribute to the trophic structure, nutrient fluxes, primary production and to the purification of entire waterbodies. Yet, there is a lack of knowledge regarding the nutrient acquisition and the contribution of algal mats and meadows to total primary production and phosphorus (P) cycling, especially in oligotrophic lakes, including post-mining lakes. Our team investigates the benthic algal primary producers - algal mats and meadows in the littoral zone of tree newly established post-mining lakes located in the Czech Republic (Europe). Our main objectives are to describe the quality and quantity of primary producers, quantify the contribution of algal mats and meadows to the primary production and phosphorus cycling in the oligotrophic post-mining lakes. We have studied them throughout all seasons with a special focus on the generally neglected winter/spring season. Our sampling strategy encompasses three gradients of variability along which the composition and ecological role of benthic algae change:spatial variability along the depth gradient within each lake,itemporal variability throughout the seasons within each lake and successional variability between the lakes of different age.The methodological approach consists of measuring the limnological and chemical parameters of lakes, taxonomic determination, biomass estimation and C:N:P stoichiometry of algal biomass along the whole gradient of the euphotic zone (0-15m). The in situ measurement of primary production of benthic algae from various depths using the oxygen meter Fibox 3 (PreSens, Germany) with a combination of laboratory experiments was employed too (Čapková 2022). We measure the kinetic parameters of P uptake of algal mats and meadows using 33P-labelled orthophosphates under controlled conditions similar to the nature (Konopáčová 2021). According to our survey, algal mats and meadows exhibited high productivity in the entire littoral zone. Algal mats dominate the depth up to 3m Fig. 1 and are highly diverse, with more than 400 identified taxa (Bešta 2022). Macroalgal meadows formed by the genus Chara together with the genus Vaucheria, are key taxa occupying the deeper zone (3-15m) Fig. 2. The distribution of benthic algae in lakes is influenced by depth gradients, substrate quality, seasonality and age of lakes foundation, resulting in complex spatio-temporal patterns. Specific emphasis is placed on the fate of P, which is the limiting nutrient in investigated lakes. High C:P molar ratios in microalgal mats indicate strong P deficiency in studied lakes. Over the vegetation season, microalgal biomass doubled, while the P content in biomass dropped to 60% of the values from the start of the vegetation season. The maximum uptake velocity and specific P uptake affinity decreased by an order of magnitude from April to October, and P uptake affinity was measured for comparison in plankton too. Based on our results, we proposed a possible mechanism underlying a stable coexistence of planktonic and benthic primary producers, with plankton prospering primarily in summer and autumn and algal mats and meadows in winter and spring seasons. By integrating data collected during five years of investigation, our study aims to provide a comprehensive understanding of the ecological roles of primary producers in post-mining lakes. HTML XML PDF
      PubDate: Thu, 12 Oct 2023 20:20:25 +030
       
  • Microbial Architects of the Cold Deserts: A Comprehensive Research of
           Biological Soil Crusts in the High-Altitudinal Cold Deserts of the Western
           Himalayas

    • Abstract: ARPHA Conference s 6: e106961
      DOI : 10.3897/aca.6.e106961
      Authors : Kateřina Čapková, Klára Řeháková : Our research has focused on Biological Soil Crusts (BSCs) in the Western Himalayas, specifically in Tibetan Plateau and Karakoram (Ladakh, India) along the elevation gradient spanning a range of 4300–6000 m a.s.l. where habitats like cold deserts, steppes, alpine and subnival vegetation, as well as primary successional stages behind retreating glaciers are present. These regions are characterised by extensive development of BSCs, with cyanobacteria as the dominant component. BSCs are of great significance for the sustainability and development of ecosystems of arid regions worldwide. Their activity is limited to brief periods when precipitation or dew hydrates microbial cells, enabling metabolic activity. Despite the crucial role played by these phototrophic microbial communities in arid and semi-arid ecosystems worldwide, remote mountain regions like the Tibetian Tibetan Plateau and Karakoram have received limited attention in this regard. More than 15 years long research allowed us to determine several critical aspects of BSCs’ activity and performance:We conducted laboratory and in-situ experiments Fig. 1 to assess the potential photosynthetic and heterotrophic activity of BSCs from high-altitude cold deserts. The experiments involved measuring the production and consumption of CO2 and O2 by BSCs under various temperature and moisture conditions, as well as light intensity. By manipulating these factors, we could differentiate the activities of heterotrophs and autotrophs within the BSCs. The results of these experiments were then analysed in the context of soil nutrient stoichiometry, phylogenetic structure, and microbial community biomass. Using these data, we developed a mechanistic mathematical model to predict the overall metabolic activity of BSCs in response to the major climatic drivers: temperature and moisture. This knowledge could help us to predict the reaction of BSC to climatic changes and reveal if the arid areas in Western Himalayas will act as CO2 sources or sink.We further investigated the composition and content of pigments in microbial soil communities across various habitats along the elevation gradient in the Tibetan Plateau (Rehakova and Capkova 2019). Soil microbes have evolved complex metabolic strategies, such as producing photoprotective and photosynthetic pigments, to survive the environmental stress caused by high UV radiation, fluctuating temperatures, and drought.We also examined the effects of environmental factors such as altitude, mountain range, and soil physico-chemical parameters on the composition and biovolume of phototrophs which dominate the BSc in the studied region (Řeháková 2011, Janatková and Řeháková 2013). This was accomplished through multivariate redundancy analysis and variance partitioning. Interestingly, the phylogenetic diversity and morphotypes’ composition were similar between the Karakoram and Tibetan Plateau (Čapková 2015). Our investigation represents the first recorded assessment of the phylogenetic diversity of cyanobacterial communities within biological soil crusts in the Western Himalayas, specifically at altitudes exceeding 5000 m. HTML XML PDF
      PubDate: Thu, 12 Oct 2023 20:14:20 +030
       
  • Integrative Genomics Sheds Light on Global Deep Terrestrial Biosphere
           Communities

    • Abstract: ARPHA Conference s 6: e106966
      DOI : 10.3897/aca.6.e106966
      Authors : Carolina González-Rosales, Maryam Rezaei Somee, Stefan Bertilsson, Maliheh Mehrshad, Mark Dopson : Active microbial lineages inhabit the deep terrestrial subsurface (Fry et al. 1997, Lopez-Fernandez et al. 2018) with estimates suggesting deep subsurface ecosystems to host ca. 90% of the total bacterial and archaeal biomass on Earth and about 10-20% of all terrestrial biomass (McMahon and Parnell 2014, Bar-On et al. 2018, Magnabosco et al. 2018, Drake and Reiners 2021). This highlights deep subsurface ecosystems as a vast reservoir of genetic innovation that remains poorly characterized. The biological diversity of deep subsurface ecosystems seem to be influenced by parameters such as temperature, pressure, water residence times, and geochemistry (Drake and Reiners 2021).The deep subsurface environment remains underrepresented in metagenomic databases, and yet the publicly available datasets are not synoptically analyzed in an integrated way. In this project, we collected a large set of publicly available and published metagenomes, published metagenome assembled genomes (MAGs) as well as single cell amplified genomes (SAGs) originating from global deep oligotrophic terrestrial subsurface samples (>70 m). Reconstructed MAGs/SAGs from this survey were integrated in to our own existing Fennoscandian Shield Genomic Database (FSGD) (Holmfeldt et al. 2021, Mehrshad et al. 2021). This expanded global database of the deep oligotrophic terrestrial subsurface contains>4000 MAGs/SAGs. In this dataset, representatives of phyla Firmicutes, Desulfobacterota, Patescibacteria, and Chlroflexota were the most prevalent taxa. The presence of Candidatus Desulforudis audaxviator across different continents and samples highlighted its adaptation to different deep biosphere environments. In addition, novel bacterial lineages at the class level were identified in several locations, pointing to the importance and necessity of further studies to characterize deep biosphere microbial diversity.This extensive study of the global deep oligotrophic terrestrial subsurface will reveal whether deep terrestrial populations are ubiquitous and how their distribution patterns are affected by different physicochemical variables such as water types and geology. By Identifying key populations present across multiple global groundwaters, our study will advance our understanding of the global diversity hosted in deep oligotrophic terrestrial subsurface ecosystems. HTML XML PDF
      PubDate: Thu, 12 Oct 2023 20:02:53 +030
       
  • Microbial pyrite formation: mineral morphology and precipitation kinetics

    • Abstract: ARPHA Conference s 6: e106753
      DOI : 10.3897/aca.6.e106753
      Authors : Muammar Mansor, Hrvoje Višić, Eric Runge, Jeremiah Shuster, Stefan Fischer, Andreas Kappler, Jan-Peter Duda : Pyrite (FeS2) is a mineral of wide interest due to its importance in the biogeochemical cycling of Fe and S, which is tied to those of carbon and other trace metals and nutrients. The mineral itself has potential applications as biosignatures, for environmental remediation and as semiconductors. Despite being a common authigenic mineral in sedimentary environments, most laboratory-based experiments have failed to form pyrite in microbial cultures at ambient temperatures. To fill this knowledge gap, we have employed cultivation-based approaches, using different combinations of microorganisms (Fe(III)- and S0-reducers; S0-disproportionaters) and initial Fe and S sources to identify the conditions that are optimal for pyrite formation. Scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffraction (XRD) demonstrate that pyrite is not formed within ~3 years at circumneutral pH when oxidants (e.g., Fe(III) minerals, elemental sulfur, S0) are exhausted. In contrast, pyrite is formed within months when S0 and Fe(III) minerals are both present. The precipitation timescale is consistent with those expected in sedimentary environments Mansor and Fantle 2019), albeit some natural pyrite framboids are expected to form even faster Rickard 2019). The pyrite crystals formed in our experiments are in the low micrometer range, with either a spherical or euhedral morphology depending on the initial crystallinity of the supplied Fe(III) minerals. Framboids are not formed in our system, perhaps due to the relatively slow precipitation kinetics. Time-based sampling indicates mackinawite (FeS) as the first product, with rare (and minor) detection of greigite (Fe3S4) and vivianite [Fe3(PO4)2.8H2O]. We hypothesize that pyrite formation and growth proceed mainly from transformation of precursor minerals, with potential contributions via dissolution-precipitation and/or particle attachment pathways. Our preliminary study is the first step in optimizing a system for microbial pyrite formation, with the intention of investigating the properties and the reactivity of the mineral with implications for biosignatures, environmental remediation and industrial applications. HTML XML PDF
      PubDate: Thu, 12 Oct 2023 19:55:01 +030
       
  • Traces of life in Río Tinto (Spain): Decoupling of morphological and
           geochemical biosignatures

    • Abstract: ARPHA Conference s 6: e106751
      DOI : 10.3897/aca.6.e106751
      Authors : Yu Pei, Philip Werner, Ricardo Amils, Eric Runge, Andreas Kappler, Jan-Peter Duda, Muammar Mansor : The Río Tinto system located in southern Spain is a 100-km long acidic (pH ≈ 2.3) river rich in dissolved iron, sulfate and heavy metals. The red-tinted river, formed as a product of natural acid rock drainage that has been exacerbated over the years by anthropogenic mining activities, hosts a variety of extremophilic microorganisms that are potential analogues to those found on early Earth and ancient Mars. Here we detailed the investigation of potential biosignatures in the forms of microbialites and sediments deposited along the river. The 20-50 cm thick microbialites (estimated age at most 100 years) are composed of layered structures of Fe(III) minerals with alternating porosities. High resolution imaging and elemental mapping coupled to mineralogical analysis suggest the transformation of K-jarosite (KFe3(SO4)2(OH)6; Vm = 153 cm3/mol) to goethite ( α -FeOOH; Vm = 21 cm3/mol), generating porosities in the process due to a reduction in the molar volume Vm. Meanwhile, riverbed sediments are composed of mixtures of schwertmannite (Fe 8 O8(OH)6(SO4) · nH2O), jarosite, goethite and other minor minerals (ferrihydrite, lepidocrocite, hematite). Culture experiments indicate that crystalline jarosite is formed via transformation from poorly-crystalline schwertmannite (Fe 8 O8(OH)6(SO4) · nH2O), but that the presence of Acidithiobacillus thiooxidans actually inhibits this transformation, possibly due to organic matter stabilization of schwertmannite. Fe isotopic analyses show no clear variations between layers in the microbialites (δ56Fe = -0.85 ± 0.10 ‰), while the riverbed sediments indicate progressively more negative values downstream over a 5-km distance (δ56Fe = +0.4 to -0.8‰). The spatial isotopic pattern of the riverbed sediments is consistent with rapid microbial oxidation of Fe2+ and inconsistent with the much slower abiotic Fe2+ oxidation rate. Taken together, our results show that while the microbialites’ structure is suggestive of microbially-induced precipitation, its geochemical features are not. Meanwhile, the inconspicuous-looking riverbed sediments provide clear evidence of biogenicity from their isotopic compositions. This highlights the challenge in detecting life especially when decoupling of morphological and geochemical biosignatures is to be expected. HTML XML PDF
      PubDate: Thu, 12 Oct 2023 19:35:33 +030
       
  • Dueling Plant Phosphorus Acquisition Strategies Over a Geochemical
           Gradient: A Biogeochemistry Experiment Approach

    • Abstract: ARPHA Conference s 6: e106663
      DOI : 10.3897/aca.6.e106663
      Authors : Kurt Reinhart, Ylva Lekberg, Lance Vermeire, Chad Penn : Plants are likely to be phosphorus (P)-limited because of low availability of P to roots or mycorrhizae due to slow diffusion and high sorption in soils.  Phosphorus sub-cycles (inorganic versus organic) also tend to vary predictably over gradients (Fig. 1A,B).  Plant responses to mycorrhizal fungi also vary by plant species and grassland type (Reinhart et al. 2017). Mycorrhizae can scavenge nutrients (i.e. orthophosphate, organic-P); however, if they cannot solubilize calcium bound P, then geochemical gradients may constrain plant-mycorrhizal interactions (Fig. 1C).Calcareous soils are found in>30% of soils and are common in arid, semiarid, and semi-humid systems (e.g. grasslands, shrublands). We used geochemical and biogeochemical experiments to test hypotheses on P limitation and acquisition (Lajtha and Schlesinger 1988). Hypothesis: an increase in soil calcium carbonate (CaCO3) will 1) reduce soil P bioavailability (geochemical exp.), 2) reduce plant biomass and phosphorus uptake (biogeochemical exp.), and 3) shift P acquisition strategies (i.e. root mining, mycorrhizal scavenging) (biogeochemical exp., Fig. 1C).Experiments had a replacement series (CaCO3 to silica sand) geochemical treatment (CaCO3 additions: 0, 0.02, 0.10, and 0.30 [g × 100 g-1]) to simulate soil properties over natural grassland gradients. The biogeochemistry experiment was a completely randomized design with the geochemical and mycorrhizal fungi treatments (+, -) (4 × 2 factorial), 8 plant species, and 8 replications.  Geochemical exp.’s response variables were soil extractable nutrients and pH. Biogeochemistry exp.’s response variables were nutrient uptake and plant performance.The geochemical experiment confirmed that increasing CaCO3 increased pHwater of subsurface soil (7.6 to 8.5), reduced the intensity of available P (assessed by anion exchange membranes) in treated soils by as much as 57%, and had no obvious effect on accessible P (Olsen-P). In other words, metaphorical cups of P (with straws) had similar amounts of accessible P per cup; however, additions of CaCO3 effectively reduced the straws’ diameter and limited (re-)supply of available P.On average, large additions of CaCO3 reduced plant biomass by 20% and plant uptake of P by 15% for the biogeochemistry experiment. On average, mycorrhizal fungi increased plant biomass by 6%.  Rarely did mycorrhizal fungi and geochemical treatments interact and affect plant biomass. When they did interact, mycorrhizae benefited plants in pots with greater levels of P intensity (i.e. no or little added CaCO3) thereby suggesting mycorrhizae may not help to solubilize calcium bound P.These findings confirm CaCO3 in subsoils reduced the intensity of bioavailable P, which consequently decreased plant biomass and P uptake. However, we cannot rule out that CaCO3 additions may have additionally impacted plants response due to changes in micronutrient solubility (i.e. zinc), etc. (Lajtha and Schlesinger 1988). While plants tended to benefit from mycorrhizae, we found no evidence to support a prediction of the nutritional mutualisms hypothesis—that benefits are greatest under P-limitation. On the contrary, our data suggest that plants will rely more on root mining P acquisition strategies than mycorrhizal scavenging (Albornoz et al. 2020) where the inorganic-P sub-cycle dominates and P solubility is limited due to calcium-phosphate formation (Fig. 1C). HTML XML PDF
      PubDate: Thu, 12 Oct 2023 19:31:56 +030
       
 
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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
Showing 1 - 200 of 265 Journals sorted alphabetically
AAS Open Research     Open Access   (Followers: 1)
Accountability in Research: Policies and Quality Assurance     Hybrid Journal   (Followers: 19)
Acta Materialia Transilvanica     Open Access  
Acta Nova     Open Access   (Followers: 2)
Acta Scientifica Malaysia     Open Access   (Followers: 1)
Acta Scientifica Naturalis     Open Access   (Followers: 4)
Adıyaman University Journal of Science     Open Access  
Advanced Science     Open Access   (Followers: 16)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 5)
Advances in Research     Open Access  
Advances in Science and Technology     Full-text available via subscription   (Followers: 18)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 7)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 1)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 3)
Alfarama Journal of Basic & Applied Sciences     Open Access   (Followers: 12)
American Academic & Scholarly Research Journal     Open Access   (Followers: 4)
American Journal of Applied Sciences     Open Access   (Followers: 22)
American Journal of Humanities and Social Sciences     Open Access   (Followers: 13)
ANALES de la Universidad Central del Ecuador     Open Access   (Followers: 1)
Anales del Instituto de la Patagonia     Open Access  
Applied Mathematics and Nonlinear Sciences     Open Access   (Followers: 2)
Apuntes de Ciencia & Sociedad     Open Access  
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 1)
Archives Internationales d'Histoire des Sciences     Partially Free   (Followers: 5)
Archives of Current Research International     Open Access  
ARO. The Scientific Journal of Koya University     Open Access  
ARPHA Conference Abstracts     Open Access   (Followers: 1)
ARPHA Proceedings     Open Access  
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access  
Asian Journal of Advanced Research and Reports     Open Access  
Asian Journal of Scientific Research     Open Access   (Followers: 2)
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 5)
Australian Field Ornithology     Full-text available via subscription   (Followers: 1)
Australian Journal of Social Issues     Hybrid Journal   (Followers: 6)
Avrasya Terim Dergisi     Open Access  
Bangladesh Journal of Scientific Research     Open Access  
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 1)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 11)
BIBECHANA     Open Access  
Bilge International Journal of Science and Technology Research     Open Access  
Bioethics Research Notes     Full-text available via subscription   (Followers: 15)
BJHS Themes     Open Access   (Followers: 2)
Black Sea Journal of Engineering and Science     Open Access  
Borneo Journal of Resource Science and Technology     Open Access  
Bulletin de la Société Royale des Sciences de Liège     Open Access  
Bulletin of the National Research Centre     Open Access  
Butlletí de la Institució Catalana d'Història Natural     Open Access  
Chain Reaction     Full-text available via subscription  
Ciencia Amazónica (Iquitos)     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia Ergo Sum     Open Access  
Ciência ET Praxis     Open Access  
Ciencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Citizen Science : Theory and Practice     Open Access   (Followers: 3)
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Communications in Applied Sciences     Open Access  
Comunicata Scientiae     Open Access  
ConCiencia     Open Access  
Conference Papers in Science     Open Access  
Configurations     Full-text available via subscription   (Followers: 11)
COSMOS     Hybrid Journal   (Followers: 1)
Crea Ciencia Revista Científica     Open Access  
Cuadernos de Investigación UNED     Open Access  
Current Issues in Criminal Justice     Hybrid Journal   (Followers: 14)
Current Research in Geoscience     Open Access   (Followers: 6)
Dalat University Journal of Science     Open Access  
Data     Open Access   (Followers: 4)
Data Curation Profiles Directory     Open Access   (Followers: 9)
Dhaka University Journal of Science     Open Access  
Diálogos Interdisciplinares     Open Access  
Digithum     Open Access   (Followers: 2)
Discover Sustainability     Open Access   (Followers: 5)
Einstein (São Paulo)     Open Access  
Ekaia : EHUko Zientzia eta Teknologia aldizkaria     Open Access  
Elkawnie : Journal of Islamic Science and Technology     Open Access  
Emergent Scientist     Open Access  
Enhancing Learning in the Social Sciences     Open Access   (Followers: 7)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Entramado     Open Access  
Entre Ciencia e Ingeniería     Open Access  
Epiphany     Open Access   (Followers: 1)
Estação Científica (UNIFAP)     Open Access  
Ethiopian Journal of Education and Sciences     Open Access   (Followers: 5)
Ethiopian Journal of Science and Technology     Open Access  
Ethiopian Journal of Sciences and Sustainable Development     Open Access  
European Online Journal of Natural and Social Sciences     Open Access   (Followers: 4)
European Scientific Journal     Open Access   (Followers: 7)
Evidência - Ciência e Biotecnologia - Interdisciplinar     Open Access  
Exchanges : the Warwick Research Journal     Open Access   (Followers: 1)
Experimental Results     Open Access   (Followers: 2)
Facets     Open Access  
Fides et Ratio : Revista de Difusión Cultural y Científica     Open Access  
Fırat University Turkish Journal of Science & Technology     Open Access  
Fontanus     Open Access   (Followers: 1)
Forensic Science Policy & Management: An International Journal     Hybrid Journal   (Followers: 247)
Frontiers for Young Minds     Open Access  
Frontiers in Climate     Open Access   (Followers: 5)
Frontiers in Science     Open Access   (Followers: 1)
Fundamental Research     Open Access  
Futures & Foresight Science     Hybrid Journal   (Followers: 1)
Gaudium Sciendi     Open Access  
Gazi University Journal of Science     Open Access  
Ghana Studies     Full-text available via subscription   (Followers: 15)
Global Journal of Pure and Applied Sciences     Full-text available via subscription  
Global Journal of Science Frontier Research     Open Access   (Followers: 1)
Globe, The     Full-text available via subscription   (Followers: 4)
HardwareX     Open Access  
Heidelberger Jahrbücher Online     Open Access  
Heliyon     Open Access   (Followers: 1)
Himalayan Journal of Science and Technology     Open Access  
History of Science and Technology     Open Access   (Followers: 6)
Hoosier Science Teacher     Open Access  
Impact     Open Access   (Followers: 1)
Indian Journal of History of Science     Hybrid Journal   (Followers: 3)
Indonesian Journal of Fundamental Sciences     Open Access  
Indonesian Journal of Science and Mathematics Education     Open Access   (Followers: 2)
Indonesian Journal of Science and Technology     Open Access  
Ingenieria y Ciencia     Open Access   (Followers: 1)
Innovare : Revista de ciencia y tecnología     Open Access  
Instruments     Open Access  
Integrated Research Advances     Open Access  
Interciencia     Open Access  
Interface Focus     Full-text available via subscription  
International Annals of Science     Open Access  
International Archives of Science and Technology     Open Access  
International Journal of Academic Research in Business, Arts & Science     Open Access  
International Journal of Advanced Multidisciplinary Research and Review     Open Access  
International Journal of Applied Science     Open Access  
International Journal of Basic and Applied Sciences     Open Access   (Followers: 1)
International Journal of Computational and Experimental Science and Engineering (IJCESEN)     Open Access  
International Journal of Culture and Modernity     Open Access   (Followers: 5)
International Journal of Engineering, Science and Technology     Open Access  
International Journal of Engineering, Technology and Natural Sciences     Open Access  
International Journal of Innovation and Applied Studies     Open Access   (Followers: 4)
International Journal of Innovative Research and Scientific Studies     Open Access   (Followers: 1)
International Journal of Network Science     Hybrid Journal   (Followers: 3)
International Journal of Recent Contributions from Engineering, Science & IT     Open Access  
International Journal of Research in Science     Open Access   (Followers: 1)
International Journal of Social Sciences and Management     Open Access   (Followers: 2)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 10)
International Letters of Social and Humanistic Sciences     Open Access  
International Science and Technology Journal of Namibia     Open Access   (Followers: 2)
International Scientific and Vocational Studies Journal     Open Access  
InterSciencePlace     Open Access  
Investiga : TEC     Open Access  
Investigación Joven     Open Access  
Investigacion y Ciencia     Open Access   (Followers: 1)
Iranian Journal of Science and Technology, Transactions A : Science     Hybrid Journal  
iScience     Open Access   (Followers: 2)
Issues in Science & Technology     Free   (Followers: 8)
Ithaca : Viaggio nella Scienza     Open Access  
J : Multidisciplinary Scientific Journal     Open Access  
Jaunujų mokslininkų darbai     Open Access   (Followers: 3)
Journal de la Recherche Scientifique de l'Universite de Lome     Full-text available via subscription  
Journal of Chromatography & Separation Techniques     Open Access   (Followers: 9)
Journal of Advanced Research     Open Access   (Followers: 2)
Journal of Al-Qadisiyah for Pure Science     Open Access  
Journal of Alasmarya University     Open Access   (Followers: 3)
Journal of Analytical Science & Technology     Open Access   (Followers: 5)
Journal of Applied Science and Technology     Full-text available via subscription   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)
Journal of Big History     Open Access   (Followers: 4)
Journal of Composites Science     Open Access   (Followers: 4)
Journal of Diversity Management     Open Access   (Followers: 4)
Journal of Indian Council of Philosophical Research     Hybrid Journal  
Journal of Institute of Science and Technology     Open Access  
Journal of Integrated Science and Technology     Open Access  
Journal of King Saud University - Science     Open Access  
Journal of Mathematical and Fundamental Sciences     Open Access  
Journal of Natural Sciences Research     Open Access   (Followers: 2)
Journal of Negative and No Positive Results     Open Access  
Journal of Responsible Technology     Open Access  
Journal of Science (JSc)     Open Access  
Journal of Science and Engineering     Open Access   (Followers: 1)
Journal of Science and Technology     Open Access   (Followers: 2)
Journal of Science and Technology     Open Access   (Followers: 1)
Journal of Science and Technology (Ghana)     Open Access   (Followers: 3)
Journal of Science and Technology Policy Management     Hybrid Journal   (Followers: 1)
Journal of Science Foundation     Open Access   (Followers: 1)
Journal of Science of the University of Kelaniya Sri Lanka     Open Access  
Journal of Scientific Research     Open Access   (Followers: 1)
Journal of Scientific Research and Reports     Open Access   (Followers: 1)
Journal of Scientometric Research     Open Access   (Followers: 22)
Journal of Shanghai Jiaotong University (Science)     Hybrid Journal  
Journal of Social Science Research     Open Access   (Followers: 2)
Journal of Taibah University for Science     Open Access  
Journal of the Asiatic Society of Bangladesh, Science     Open Access  
Journal of the Ghana Science Association     Full-text available via subscription   (Followers: 3)
Journal of the History of Ideas     Full-text available via subscription   (Followers: 168)
Journal of the Indian Institute of Science     Hybrid Journal   (Followers: 4)
Journal of the National Science Foundation of Sri Lanka     Open Access  
Journal of the Royal Society of New Zealand     Hybrid Journal   (Followers: 49)
Journal of the South Carolina Academy of Science     Open Access  
Journal of Unsolved Questions     Open Access  
Jurnal Ilmiah Ilmu Terapan Universitas Jambi : JIITUJ     Open Access  
Jurnal Matematika, Sains, Dan Teknologi     Open Access  

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