 Subjects -> WATER RESOURCES (Total: 160 journals)
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z | | We no longer collect new content from this publisher because the publisher has forbidden systematic access to its RSS feeds. |
|
|
- Phytoplankton community as monitoring tool in the terminal stretch of a
micro-tidal estuary facing the Tyrrhenian Sea
Authors: Francesco Bolinesi, Emanuela Serino, Angelo Carotenuto, Silvia Fanina, Olga Mangoni
Abstract: Mediterranean coastal systems, particularly those characterized by river mouths, have played an important role in the history of human civilization, thanks to unique species assemblages, a high biodiversity, and complex ecological interactions. The overlapping of multiple cross-scale effects, triggered by the ongoing climate change, makes these systems particularly important sites for ecological studies. Here, we have investigated the phytoplankton community structure in the terminal stretch of the Sele River (Tyrrhenian Sea) under two different hydrological regimes: i) with river mouth occluded by sediments preventing water exchange with the sea; ii) with river mouth completely opened, which allowed the maximum water mass exchanges between the river and the sea. The strong variations in physical-chemical properties of the water column, the point-distribution of total phytoplankton biomass, and the dominance of cryptophytes and cyanophytes under occluded and opened river mouth, respectively, indicate the presence of strong allogenic pressures acting on the system. Our data suggest that the monitoring of phytoplankton communities in the terminal stretch of micro-tidal estuaries, could be a useful tool for studying the extent of climate change underway in Mediterranean coastal marine areas.
PubDate: 2023-08-03
DOI: 10.4081/aiol.2023.11070
Issue No: Vol. 14, No. 1 (2023)
- Erratum - Macrobenthos of lagoon ecosystems: a comparison in vegetated and
bare sediments
Authors: Paolo Magni, Maria Flavia Gravina
Abstract: This corrects the article published on Advances in Oceanography and Limnology 2023;14:11124 doi: https://doi.org/10.4081/aiol.2023.11124
PubDate: 2023-07-31
DOI: 10.4081/aiol.2023.11613
Issue No: Vol. 14, No. 1 (2023)
- Dissolved fluxes of nutrients and carbon at the sediment-water interface
in the Adriatic Sea: review of early data and methods from the Italian
National Research Council (CNR)
Authors: Federico Spagnoli, Mariangela Ravaioli
Abstract: We report the measurement of the Fluxes of Dissolved Compounds at the Sediment-Water Interface (DFSWIs), obtained by analyzing data collected in the Italian Exclusive Economic Zone (EEZ) of the Northern and Central Adriatic Sea from 1982. We also describe the methods, honed by Italy’s Consiglio Nazionale delle Ricerche (CNR), employed to measure and calculate DFSWIs, including benthic chambers and landers, sediment-water interface micro-profiling, on-board incubation, and pore water modeling. Data analysis demonstrated that in situ measurements are the most reliable approaches, but that on-board collected data also supply interesting results. The DFSWI data allowed to divide the Adriatic seafloor into areas with similar DFSWI types and intensities and to define the role of sediments as sources or sinks of chemicals such as nutrients, Dissolved Inorganic Carbon (DIC), and metals. DFSWIs mainly depend on dissolved and solid river inputs, Marine Organic Matter (mOM) production, and sediment reworking. They show a seasonal temperature-related trend, which in summer induces increased chemical reaction kinetics and microbial activity. DFSWIs decline from the Po River mouths southward, along the Holocene mud wedge. North of the Po River Delta, the DFSWIs are weaker and confined to the areas in front of the major river mouths, due to poor Organic Matter (OM) inputs and strong reworking of bottom sediments. The area south of the Po Delta cusp is characterized by strong DFSWIs, due to the high deposition of solid inputs from the Po River, strong primary production, and protection from the Western Adriatic Current and Bora storms; in summer, higher temperatures, and calm hydrodynamic conditions generate near-bottom hypoxic to anoxic environments in this area. In Northern and Central Adriatic offshore areas, negative DIC and phosphate fluxes are due to poorly reactive OM reaching this area and to the mainly carbonate composition and oxic environment of local bottom sediments. DFSWI data analysis highlighted the important contribution of sediments to marine carbon and nutrient cycles. This is particularly important for carbon, which plays a major role in seawater acidification and global climate change. The study also provides average DFSWI data for each diagenetic area, which allow calculating the carbon and nutrient budgets in the Adriatic Sea.
PubDate: 2023-06-22
DOI: 10.4081/aiol.2023.11094
Issue No: Vol. 14, No. 1 (2023)
- Dominance of small-sized phytoplankton in a Mediterranean eutrophic
coastal lagoon
Authors: Silvia Pulina, Cecilia Teodora Satta, Bachisio Mario Padedda, Jacopo Culurgioni, Riccardo Diciotti, Nicola Fois, Antonella Lugliè
Abstract: The predator-prey relationship is generally size-specific in the pelagic food webs. Phytoplankton cell size structure can provide information on the successive levels of consumers and therefore on the energy that can flow towards the top consumers. This work focuses on phytoplankton cell size structure in a coastal lagoon (Cabras Lagoon, Italy) considered one of the most important for fishing productivity in the Mediterranean. The inter-annual and seasonal dynamics of picophytoplankton (Pico, cell size <3 μm) and Utermöhl Fraction of Phytoplankton (UFP, cell size >3 μm) were considered during almost three years in relation to the temporal dynamics of selected environmental variables and zooplankton. Small-sized cells with a mean linear cell size <10 μm and a mean cell volume <103 μm3 mainly represented UFP along the entire study period. This size class contributed the most to total phytoplankton biomass (up to 86%) and density (up to 99%) during the first part of the investigation period. A compositional change was detected: smaller species of Chlorophyceae, Bacillariophyceae, filamentous Cyanophyceae, and autotrophic nanoflagellates thrived in the second part of the study, replacing larger Mediophyceae that dominated UFP at the beginning. Picocyanobacteria rich in phycocyanin were the dominant taxa of Pico along the entire investigation period and this size class contributed the most to total phytoplankton biomass (up to 30%) and density (up to 96%) at the end of the study. The observed shift towards different and even smaller UFP and Pico in the second part of the study was most probably due to complex interactions between top-down and bottom-up effects. Indeed, an increased temperature, a decreased salinity and decreased concentrations of nutrients (mainly ammonium and orthophosphate), as well as an increased grazing pressure of rotifers on the larger Mediophyceae were simultaneous with the changes detected in phytoplankton. The obtained results highlight a longer planktonic trophic web in Cabras Lagoon that includes small phytoplankton at the base, ciliates, rotifers, and copepods. This suggests low energy availability for planktivorous fish, with possible future relevant consequences for fishing activities in this coastal lagoon.
PubDate: 2023-06-20
DOI: 10.4081/aiol.2023.11112
Issue No: Vol. 14, No. 1 (2023)
- Macrobenthos of lagoon ecosystems: a comparison in vegetated and bare
sediments
Authors: Paolo Magni, Maria Flavia Gravina
Abstract: The classic paradigm, not always unequivocal though, that seagrass macrobenthic abundance and diversity are greater than those in adjacent unvegetated areas, was tested in a Mediterranean lagoon for which evidence is lacking. We compared the community structure and species composition of macrobenthic assemblages in three distinct areas of the Mistras Lagoon (Sardinia, Italy) dominated by i) the seagrass Cymodocea nodosa (Cym), ii) mixed-macrophyte/detritus (Mix), and iii) unvegetated sediments (Unv). Samplings were conducted in each area twice in spring (April and May) and twice in autumn (October and November) 2010. Multivariate analyses showed significant differences among the three areas and a marked separation between the two vegetated (Cym and Mix) and the unvegetated (Unv) areas. The top discriminating species, indicated by SIMPER analysis, were characterized by direct development lacking free living larvae. They included marine species, e.g. Cerithium lividulum, Microdeutopus gryllotalpa, Loripes orbiculatus and Gammarus aequicauda, at Cym vs Mix, whereas the pair discrimination of the areas Cym vs Unv and Mix vs Unv mostly depended on the marine Abra tenuis, the opportunistic Chironomidae and Capitella capitata, and the brackish Hydrobia acuta. Both vegetated areas showed a higher species number than the unvegetated area. Differently, abundance was higher in Unv than in Cym and Mix in all sampling dates, most notably in spring likely because of reproductive events, due to both opportunistic (C. capitata, chironomids) and halolimnobic (H. acuta, Cerastoderma glaucum) species. Overall, the present study demonstrated the importance of biological factors in structuring the macrobenthic assemblages of the Mistras Lagoon. Habitatforming phanerogams hosted species-rich assemblages, species-specific reproductive cycles and adaptive strategies contributed to drive species colonization and abundance distribution. Both vegetated and unvegetated patches were found to contribute greatly to the local-scale heterogeneity of the habitat, highlighting the importance of coastal lagoons as hotspots for benthic biodiversity. For these reasons, lagoons must be considered major targets for conservation measures.
PubDate: 2023-05-19
DOI: 10.4081/aiol.2023.11124
Issue No: Vol. 14, No. 1 (2023)
- Geographical, environmental, and biotic constraints define the spatial
distribution of Diaphanosoma species (Cladocera)
Authors: Jaielle R. Nascimento, Louizi S.M. Braghin, Camila R. Cabral, Adriano Caliman, Nadson R. Simões
Abstract: Species distribution is a combination of ecological, historical, stochastic, and evolutionary mechanisms, and is a process that has been severely impacted by anthropogenic activities. Freshwater zooplankton is adequate to assess that combination because it groups cosmopolitan and endemic species. We hypothesized that the spatial distribution of Diaphanosoma species is defined by a complex interaction between factors such as spatial limitation, limitation of environmental conditions, and ecological conditions. We georeferenced the occurrence of Diaphanosoma in Brazil to study the potential distribution of the species, preference of ecoregions, environmental features associated with Diaphanosoma, and their co-occurring patterns. Five species of Diaphanosoma are widely distributed in Brazil. D. spinulosum and D. birgei were widely distributed while D. fluviatile and D. polyspina had a more restricted distribution. The occurrences of Diaphanosoma species were shown to have an association with factors such as the total concentrations of nitrogen and phosphorus, pH and, temperature, except in the case of the D. brevireme. Our results show that geographic, environmental, and biotic filters can drive the spatial distribution of species of the genus Diaphanosoma. Therefore, the distribution and spatial occurrence of these species depend on dispersal capacity and spatial restrictions, suitability of the abiotic environment, and ecological interactions.
PubDate: 2023-05-19
DOI: 10.4081/aiol.2023.10848
Issue No: Vol. 14, No. 1 (2023)
|
Open Access journal
