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Publisher: Springer-Verlag (Total: 2350 journals)

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Showing 1 - 200 of 2350 Journals sorted alphabetically
3D Printing in Medicine     Open Access  
3D Research     Hybrid Journal   (Followers: 20, SJR: 0.214, h-index: 10)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 10, SJR: 1.073, h-index: 25)
AAPS J.     Hybrid Journal   (Followers: 21, SJR: 1.192, h-index: 74)
AAPS PharmSciTech     Hybrid Journal   (Followers: 7, SJR: 0.718, h-index: 54)
Abdominal Imaging     Hybrid Journal   (Followers: 14, SJR: 0.723, h-index: 60)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 4, SJR: 0.447, h-index: 12)
Academic Psychiatry     Full-text available via subscription   (Followers: 23, SJR: 0.492, h-index: 32)
Academic Questions     Hybrid Journal   (Followers: 8, SJR: 0.135, h-index: 6)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26, SJR: 0.378, h-index: 30)
Acoustical Physics     Hybrid Journal   (Followers: 11, SJR: 0.355, h-index: 20)
Acoustics Australia     Hybrid Journal  
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.387, h-index: 6)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.624, h-index: 34)
Acta Biotheoretica     Hybrid Journal   (Followers: 4, SJR: 0.419, h-index: 25)
Acta Diabetologica     Hybrid Journal   (Followers: 16, SJR: 1.318, h-index: 46)
Acta Endoscopica     Hybrid Journal   (Followers: 1, SJR: 0.113, h-index: 8)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.465, h-index: 23)
Acta Geochimica     Hybrid Journal   (Followers: 6)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 2, SJR: 0.294, h-index: 13)
Acta Geotechnica     Hybrid Journal   (Followers: 7, SJR: 1.818, h-index: 22)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.524, h-index: 32)
Acta Mathematica     Hybrid Journal   (Followers: 12, SJR: 8.021, h-index: 47)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.53, h-index: 29)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 6, SJR: 0.406, h-index: 30)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.451, h-index: 5)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.22, h-index: 20)
Acta Mechanica     Hybrid Journal   (Followers: 21, SJR: 0.898, h-index: 52)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 5, SJR: 0.426, h-index: 29)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7, SJR: 0.525, h-index: 18)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.524, h-index: 14)
Acta Neurochirurgica     Hybrid Journal   (Followers: 6, SJR: 0.833, h-index: 73)
Acta Neurologica Belgica     Hybrid Journal   (Followers: 1, SJR: 0.348, h-index: 27)
Acta Neuropathologica     Hybrid Journal   (Followers: 5, SJR: 6.61, h-index: 117)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 17)
Acta Parasitologica     Hybrid Journal   (Followers: 10, SJR: 0.581, h-index: 28)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 2, SJR: 0.551, h-index: 39)
Acta Politica     Hybrid Journal   (Followers: 13, SJR: 0.658, h-index: 20)
Activitas Nervosa Superior     Hybrid Journal  
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 6, SJR: 0.103, h-index: 4)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 22, SJR: 0.871, h-index: 15)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 15, SJR: 0.795, h-index: 40)
Adsorption     Hybrid Journal   (Followers: 4, SJR: 0.774, h-index: 52)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 4, SJR: 0.319, h-index: 15)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 36, SJR: 0.959, h-index: 44)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19, SJR: 1.255, h-index: 44)
Advances in Contraception     Hybrid Journal   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51, SJR: 1.113, h-index: 14)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.141, h-index: 3)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 27, SJR: 1.397, h-index: 42)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.2, h-index: 4)
Advances in Polymer Science     Hybrid Journal   (Followers: 43, SJR: 0.637, h-index: 89)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 0.79, h-index: 44)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.882, h-index: 23)
Aerobiologia     Hybrid Journal   (Followers: 3, SJR: 0.511, h-index: 36)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 9, SJR: 0.821, h-index: 49)
African Archaeological Review     Hybrid Journal   (Followers: 16, SJR: 0.612, h-index: 24)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.248, h-index: 6)
AGE     Hybrid Journal   (Followers: 7, SJR: 1.358, h-index: 33)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.337, h-index: 10)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.529, h-index: 55)
Agricultural Research     Hybrid Journal   (Followers: 4)
Agriculture and Human Values     Hybrid Journal   (Followers: 14, SJR: 1.197, h-index: 49)
Agroforestry Systems     Hybrid Journal   (Followers: 19, SJR: 0.64, h-index: 56)
Agronomy for Sustainable Development     Hybrid Journal   (Followers: 11, SJR: 1.732, h-index: 59)
AI & Society     Hybrid Journal   (Followers: 8, SJR: 0.171, h-index: 19)
AIDS and Behavior     Hybrid Journal   (Followers: 13, SJR: 2.006, h-index: 71)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 4, SJR: 0.706, h-index: 19)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 5, SJR: 0.566, h-index: 18)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.388, h-index: 22)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 0.868, h-index: 20)
Algorithmica     Hybrid Journal   (Followers: 8, SJR: 0.898, h-index: 56)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.183, h-index: 20)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 5, SJR: 0.729, h-index: 20)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3, SJR: 1.392, h-index: 32)
AMBIO     Hybrid Journal   (Followers: 11, SJR: 1.094, h-index: 87)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 16, SJR: 0.864, h-index: 39)
American J. of Community Psychology     Hybrid Journal   (Followers: 27, SJR: 1.237, h-index: 83)
American J. of Criminal Justice     Hybrid Journal   (Followers: 8, SJR: 0.634, h-index: 13)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 15, SJR: 0.283, h-index: 3)
American J. of Dance Therapy     Hybrid Journal   (Followers: 4, SJR: 0.175, h-index: 13)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.558, h-index: 35)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 20, SJR: 0.293, h-index: 13)
American Sociologist     Hybrid Journal   (Followers: 12, SJR: 0.18, h-index: 13)
Amino Acids     Hybrid Journal   (Followers: 8, SJR: 1.362, h-index: 83)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7, SJR: 0.21, h-index: 37)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 5, SJR: 0.665, h-index: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 5)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 32, SJR: 1.096, h-index: 123)
Anatomical Science Intl.     Hybrid Journal   (Followers: 2, SJR: 0.301, h-index: 26)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.212, h-index: 69)
Animal Cognition     Hybrid Journal   (Followers: 18, SJR: 1.122, h-index: 55)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.156, h-index: 4)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.377, h-index: 32)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.504, h-index: 14)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.167, h-index: 26)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18, SJR: 1.182, h-index: 94)
Annals of Combinatorics     Hybrid Journal   (Followers: 4, SJR: 0.849, h-index: 15)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Dyslexia     Hybrid Journal   (Followers: 10, SJR: 0.857, h-index: 40)
Annals of Finance     Hybrid Journal   (Followers: 29, SJR: 0.686, h-index: 14)
Annals of Forest Science     Hybrid Journal   (Followers: 7, SJR: 0.929, h-index: 57)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.136, h-index: 23)
Annals of Hematology     Hybrid Journal   (Followers: 16, SJR: 1.117, h-index: 62)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12, SJR: 0.593, h-index: 42)
Annals of Microbiology     Hybrid Journal   (Followers: 10, SJR: 0.402, h-index: 26)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 4, SJR: 0.68, h-index: 45)
Annals of Operations Research     Hybrid Journal   (Followers: 10, SJR: 1.186, h-index: 78)
Annals of Ophthalmology     Hybrid Journal   (Followers: 12)
Annals of Regional Science     Hybrid Journal   (Followers: 7, SJR: 0.405, h-index: 42)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 9, SJR: 0.553, h-index: 8)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 14, SJR: 1.902, h-index: 127)
Annals of Telecommunications     Hybrid Journal   (Followers: 9, SJR: 0.315, h-index: 25)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.931, h-index: 31)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.992, h-index: 87)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.14, h-index: 57)
APOPTOSIS     Hybrid Journal   (Followers: 8, SJR: 1.554, h-index: 87)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.354, h-index: 27)
Applications of Mathematics     Hybrid Journal   (Followers: 2, SJR: 0.274, h-index: 20)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 42, SJR: 0.575, h-index: 80)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 16, SJR: 0.267, h-index: 26)
Applied Cancer Research     Open Access  
Applied Categorical Structures     Hybrid Journal   (Followers: 2, SJR: 0.361, h-index: 21)
Applied Composite Materials     Hybrid Journal   (Followers: 49, SJR: 0.705, h-index: 35)
Applied Entomology and Zoology     Partially Free   (Followers: 3, SJR: 0.554, h-index: 34)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.323, h-index: 9)
Applied Geophysics     Hybrid Journal   (Followers: 8, SJR: 0.541, h-index: 13)
Applied Intelligence     Hybrid Journal   (Followers: 11, SJR: 0.777, h-index: 43)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4, SJR: 0.358, h-index: 34)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 6, SJR: 0.955, h-index: 33)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (SJR: 0.275, h-index: 8)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.37, h-index: 26)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 63, SJR: 1.262, h-index: 161)
Applied Physics A     Hybrid Journal   (Followers: 9, SJR: 0.535, h-index: 121)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 24, SJR: 0.983, h-index: 104)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 8, SJR: 0.677, h-index: 47)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 11, SJR: 0.288, h-index: 15)
Applied Solar Energy     Hybrid Journal   (Followers: 18, SJR: 0.251, h-index: 6)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4, SJR: 0.351, h-index: 9)
Aquaculture Intl.     Hybrid Journal   (Followers: 22, SJR: 0.613, h-index: 40)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 1)
Aquatic Ecology     Hybrid Journal   (Followers: 33, SJR: 0.646, h-index: 44)
Aquatic Geochemistry     Hybrid Journal   (Followers: 4, SJR: 0.764, h-index: 39)
Aquatic Sciences     Hybrid Journal   (Followers: 13, SJR: 1.172, h-index: 53)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.345, h-index: 20)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 2, SJR: 0.417, h-index: 16)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 20, SJR: 1.056, h-index: 15)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.397, h-index: 13)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.597, h-index: 29)
Archival Science     Hybrid Journal   (Followers: 58, SJR: 0.804, h-index: 22)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 8, SJR: 0.28, h-index: 15)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 2, SJR: 0.946, h-index: 23)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 4.091, h-index: 66)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.865, h-index: 40)
Archives and Museum Informatics     Hybrid Journal   (Followers: 140)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5, SJR: 2.841, h-index: 40)
Archives of Dermatological Research     Hybrid Journal   (Followers: 7, SJR: 0.9, h-index: 65)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 14, SJR: 0.846, h-index: 84)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 16, SJR: 0.695, h-index: 47)
Archives of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.702, h-index: 85)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 8, SJR: 1.039, h-index: 56)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 1.092, h-index: 13)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 10, SJR: 1.198, h-index: 74)
Archives of Toxicology     Hybrid Journal   (Followers: 17, SJR: 1.595, h-index: 76)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 1.086, h-index: 90)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 14, SJR: 1.264, h-index: 50)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 1.2, h-index: 42)
ArgoSpine News & J.     Hybrid Journal   (SJR: 0.102, h-index: 3)
Argumentation     Hybrid Journal   (Followers: 5, SJR: 0.295, h-index: 18)
Arid Ecosystems     Hybrid Journal   (Followers: 2)
Arkiv för Matematik     Hybrid Journal   (Followers: 1, SJR: 0.948, h-index: 22)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.797, h-index: 17)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.145, h-index: 8)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 11, SJR: 0.288, h-index: 25)
Artificial Intelligence Review     Hybrid Journal   (Followers: 14, SJR: 0.948, h-index: 48)
Artificial Life and Robotics     Hybrid Journal   (Followers: 9, SJR: 0.231, h-index: 14)
Asia Europe J.     Hybrid Journal   (Followers: 5, SJR: 0.247, h-index: 9)
Asia Pacific Education Review     Hybrid Journal   (Followers: 11, SJR: 0.371, h-index: 17)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 16, SJR: 1.676, h-index: 50)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 12, SJR: 0.353, h-index: 13)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 2, SJR: 0.19, h-index: 15)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 19, SJR: 1.006, h-index: 14)
Asian Business & Management     Hybrid Journal   (Followers: 9, SJR: 0.41, h-index: 10)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 9)
Asian J. of Criminology     Hybrid Journal   (Followers: 5, SJR: 0.263, h-index: 8)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 2, SJR: 0.681, h-index: 15)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.195, h-index: 5)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  

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Journal Cover Aquatic Sciences
  [SJR: 1.172]   [H-I: 53]   [13 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1015-1621 - ISSN (Online) 1420-9055
   Published by Springer-Verlag Homepage  [2350 journals]
  • Downstream impacts of dams: shifts in benthic invertivorous fish
           assemblages
    • Authors: Rafaela Vendrametto Granzotti; Leandro Esteban Miranda; Angelo Antonio Agostinho; Luiz Carlos Gomes
      Abstract: Impoundments alter connectivity, sediment transport and water discharge in rivers and floodplains, affecting recruitment, habitat and resource availability for fish including benthic invertivorous fish, which represent an important link between primary producers and higher trophic levels in tropical aquatic ecosystems. We investigated long-term changes to water regime, water quality, and invertivorous fish assemblages pre and post impoundment in three rivers downstream of Porto Primavera Reservoir in south Brazil: Paraná, Baía and Ivinhema rivers. Impacts were distinct in the Paraná River, which is fully obstructed by the dam, less evident in the Baía River which is partially obstructed by the dam, but absent in the unimpounded Ivinhema River. Changes in water regime were reflected mainly as changes in water-level fluctuation with little effect on timing. Water transparency increased in the Paraná River post impoundment but did not change in the Baía and Ivinhema rivers. Changes in fish assemblages included a decrease in benthic invertivorous fish in the Paraná River and a shift in invertivorous fish assemblage structure in the Baía and Paraná rivers but not in the unimpounded Ivinhema River. Changes in water regime and water transparency, caused by impoundment, directly or indirectly impacted invertivorous fish assemblages. Alterations of fish assemblages following environmental changes have consequences over the entire ecosystem, including a potential decrease in the diversity of mechanisms for energy flow. We suggest that keeping existing unimpounded tributaries free of dams, engineering artificial floods, and intensive management of fish habitat within the floodplain may preserve native fish assemblages and help maintain functionality and ecosystem services in highly impounded rivers.
      PubDate: 2018-04-23
      DOI: 10.1007/s00027-018-0579-y
      Issue No: Vol. 80, No. 3 (2018)
       
  • Impacts of elevated atmospheric CO 2 concentration on terrestrial-aquatic
           carbon transfer and a downstream aquatic microbial community
    • Authors: Emma Rochelle-Newall; Audrey Niboyet; Ludwig Jardiller; Sarah Fiorini; Simon Chollet; Mathieu Llavata; Elisa de Santis; Sébastien Barot; Gérard Lacroix
      Abstract: Under higher atmospheric CO2 concentrations, increases in soil moisture and, hence in terrestrial-aquatic carbon transfer are probable. In a coupled terrestrial-aquatic experiment we examined the direct (e.g. through changes in the CO2 water concentration) and indirect (e.g. through changes in the quality and quantity of soil leachates) effects of elevated CO2 on a lake microbial community. The incubation of soils under elevated CO2 resulted in an increase in the volume of leachates and in both chromophoric dissolved organic matter (CDOM) absorption and fluorescence in leachate. When this leachate was added to lake water during a 3-day aquatic incubation, we observed negative direct effects of elevated CO2 on photosynthetic microorganism abundance and a positive, indirect effect on heterotrophic microbial community cell abundances. We also observed a strong, indirect impact on the functional structure of the community with higher metabolic capacities under elevated CO2 along with a significant direct effect on CDOM absorption. All of these changes point to a shift towards heterotrophic processes in the aquatic compartment under higher atmospheric CO2 concentrations.
      PubDate: 2018-04-21
      DOI: 10.1007/s00027-018-0577-0
      Issue No: Vol. 80, No. 3 (2018)
       
  • Contribution of humic substances to dissolved organic matter optical
           properties and iron mobilization
    • Authors: Morimaru Kida; Nobuhide Fujitake; Vilanee Suchewaboripont; Sasitorn Poungparn; Mitsutoshi Tomotsune; Miyuki Kondo; Shinpei Yoshitake; Yasuo Iimura; Kazutoshi Kinjo; Chatree Maknual; Toshiyuki Ohtsuka
      Abstract: Humic substances (HS) are the primary constituents of dissolved organic matter (DOM) and play pivotal roles in aquatic systems. Optical indices of DOM, such as specific UV absorbance (SUVA254), the fluorescence index (FI) and biological index (BIX), have gained wide interest because of their ease of use. In this study, we explored the relationship between HS and the indices in the Trat River Basin (eastern Thailand) from headwaters to the river mouth through the distinct dry and rainy seasons to examine whether changes in index values reflect variability in the relative contribution of HS to DOM, or %HS. The results show that %HS and the indices did not exhibit significant linear relationships (FI and BIX, P > 0.05), or the relationships changed seasonally (SUVA254). However, analyzing the indices versus %HS did show clear DOM composition changes by season with more humic-like or terrestrial material in the rainy season. Relationships between DOM and dissolved iron (dFe) concentrations were also explored. Separating the relationships of DOM versus dFe into HS versus dFe and non-HS versus dFe provides us the opportunity to better understand which fraction contributes more to dFe mobilization. The results indicate stronger positive linear relationships between HS and dFe concentrations independent of river tributary. Overall, this study highlights the importance of quantifying HS for the study of DOM dynamics or compositional changes along a river transect as well as for DOM-induced iron mobilization.
      PubDate: 2018-04-20
      DOI: 10.1007/s00027-018-0578-z
      Issue No: Vol. 80, No. 3 (2018)
       
  • Limited resilience in hotspots of functional richness: the Mediterranean
           riparian shrublands
    • Authors: Ivana Lozanovska; Maria Teresa Ferreira; Pedro Segurado; Francisca C. Aguiar
      Abstract: Functional diversity indices are increasingly being used to describe plant community assembly processes and ecosystem functioning. However, their relevance for predicting alterations in ecosystem functioning of riparian plant communities is still largely unknown. We investigated the functional patterns of riparian forests along environmental gradients, using biological and environmental data from 189 well-preserved riverine locations in mainland Portugal. We calculated functional diversity indices (e.g. Richness, Redundancy, Divergence) for four riparian forest types, namely the Alder woodlands, Ash woodlands, Tree-heath shrublands and Mediterranean shrublands, using their plant species composition and 25 plant functional traits. We used multiple linear regression to predict the effect of the environment in the functional structure of riparian forests and ultimately evaluate the resilience of the riparian forests to environmental fluctuations. We found that Mediterranean shrublands have a significantly higher Functional Richness and a lower Functional Redundancy in comparison to the other riparian forest types. Both regional and habitat variables were important for predicting the functional diversity of riparian forests, with varying patterns according to forest types. In particular, we found that the redundancy of Mediterranean shrublands is mostly affected by precipitation, suggesting their potential vulnerability to climate change in the study area. Our results suggest the usefulness of functional diversity measures for conservation and monitoring the ecological functioning of riparian forests.
      PubDate: 2018-04-06
      DOI: 10.1007/s00027-018-0576-1
      Issue No: Vol. 80, No. 3 (2018)
       
  • Contrasting plankton stoichiometry and nutrient regeneration in northern
           arctic and boreal lakes
    • Authors: Ann-Kristin Bergström; Jan Karlsson; Daniel Karlsson; Tobias Vrede
      Abstract: Contrasting carbon: nitrogen: phosphorus (C: N: P) stoichiometry between phytoplankton and zooplankton affect consumer growth and phytoplankton nutrient limitation via nutrient recycling by zooplankton. However, no study has assessed how regional differences in terrestrial loadings of organic matter affect plankton N: P stoichiometry and recycling in systems with low N deposition and N-limited phytoplankton. We address this question by using data from 14 unproductive headwater arctic and boreal lakes. We found that boreal lakes had higher lake water- and seston C, N and P concentrations than arctic lakes, whereas seston C: N, C: P and N: P ratios did not differ among regions. Boreal zooplankton were also richer in N and P relative to C, with lower somatic N: P ratios, compared to arctic lakes. Consequently, the estimated N: P imbalances between seston and zooplankton were negative in arctic lakes, indicating zooplankton feeding on phytoplankton of suboptimal N content, resulting in low consumer driven N: P recycling (medians arctic sub-mid and high altitude lakes: 11 and 13). In boreal lakes, estimated N: P imbalance did not differ from zero, with a seston N: P stoichiometry matching the N:P requirements of zooplankton, which resulted in higher consumer driven N: P recycling (median 18). Our results imply that regional climate induced catchment differences, through enhanced terrestrial nutrient inputs, affect plankton stoichiometry by raising consumer N: P recycling ratio and changing zooplankton from being mainly N- (arctic) to NP co-limited (boreal). Browning of lakes, in regions with low N deposition, may therefore promote large-scale regional changes in plankton nutrient limitation with potential feedbacks on pelagic food webs.
      PubDate: 2018-03-29
      DOI: 10.1007/s00027-018-0575-2
      Issue No: Vol. 80, No. 2 (2018)
       
  • Seed bank dynamics in wetland complexes associated with a lowland river
    • Authors: D. L. Nielsen; C. Campbell; G. N. Rees; R. Durant; R. Littler; R. Petrie
      Abstract: The existence of a dormant “bank” of plant seeds plays an important role in maintaining and preserving species and genetic diversity. However, information on the spatial heterogeneity of the pool of dormant seeds among wetland complexes along riverine systems is limited. In this study we collected sediment from 18 wetlands within six wetland complexes along the Murray River, Australia. The germinable, residual and viable seed banks in each wetland complex were assessed by undertaking a germination trial, counting seeds (morphotypes) and viability testing. A diverse and viable seed bank exists within all the complexes however seed bank communities differed among wetland complexes. There was no difference in the viability of seeds within the sediment profile, however more seeds occurred in the surface layers of sediment and communities differed with sediment profile depth. In general, the number of species germinating was fewer than the number of seed morphotypes counted. Management actions need to be targeted not only at preserving the extant plant communities but also to ensure the seed bank is replenished. This may also involve allowing wetlands to dry sufficiently to enable cracking of wetland sediment and seeds to become buried to maximise the longevity of the seed store.
      PubDate: 2018-03-26
      DOI: 10.1007/s00027-018-0574-3
      Issue No: Vol. 80, No. 2 (2018)
       
  • Differences in the distribution and optical properties of DOM between
           fresh and saline lakes in a semi-arid area of Northern China
    • Authors: Zhidan Wen; Kaishan Song; Yingxin Shang; Ying Zhao; Chong Fang; Lili Lyu
      Abstract: In limnological environments, most organic carbon is present in the dissolved form. Dissolved organic carbon (DOC) is the main source of energy for microbial metabolism and biosynthesis, and also affects photosynthetic radiation level and the attenuation of ultraviolet irradiation to protect aquatic organisms. There are large differences in DOC concentration, source, and characteristics due to regional variations in water quality and basin characteristics. Reliable estimates of DOC and analysis of optical characteristics are crucial to understand the true role of lakes in the global carbon cycle. In this article, the distribution of DOC across 30 lakes in semi-arid areas of Northern China is reported. The data shows that saline lakes exhibited higher DOC concentrations than freshwater lakes, and the positive relationship between salinity and DOC was established (R2 = 0.42, p < 0.01, n = 196). The mean DOC concentration in eutrophic lakes was lower than in mesotrophic and oligotrophic lakes. Analysis of optical characteristics of CDOM indicated that saline lakes in this semi-arid regions contained abundant fulvic acid, and greater levels of autochthonous dissolved organic matter (DOM) with a lower molecular mass than fresh waters. The total suspended matter (TSM) is the main factor influencing on SUVA254 in both freshwater and saline lakes with a negative correlation. SUVA254 was negatively correlated with the salinity only in freshwater lakes, and with pH only in saline lakes. The result suggests that it was doubtful whether CDOM or SUVA254 alone can be a predictor of DOC concentration and other water quality parameters, especially in different types of lakes with different optical and physicochemical characteristics.
      PubDate: 2018-02-26
      DOI: 10.1007/s00027-018-0572-5
      Issue No: Vol. 80, No. 2 (2018)
       
  • Post-wildfire recovery of invertebrate diversity in drought-affected
           headwater streams
    • Authors: B. J. Robson; E. T. Chester; T. G. Matthews; K. Johnston
      Abstract: As climate change progresses, large (> 400 km2) fires are becoming more frequent across many biomes, often in association with intense drought. We analysed 5 years of stream macroinvertebrate data, collected before and after a wildfire that burnt > 750 km2 of the Grampians National Park, Australia. The wildfire occurred in 2006, during a 12-year drought (1997–2009). We tested the hypotheses that wildfire alters macroinvertebrate assemblage composition, and reduces taxon richness and among-stream variation. Five burnt and five unburnt headwater stream reaches were compared before and after the fire; a larger number of reaches were used to examine temporal trends in taxon richness. Wildfire altered macroinvertebrate assemblage composition and reduced among-stream variation in assemblages, but was not associated with low reach-scale taxon richness. Fire was associated with increased abundances of predators specialised for soft-sediments, and with reduced abundances of shredding and algal grazing caddisflies. In the short term, suspension feeder abundances increased, overwhelming the negative effects of drought on their abundance. Within 2 years post-fire, assemblages in burnt streams were similar to unburnt streams; within 3 years, among-reach variability in assemblage composition among burnt streams resembled that in unburnt streams. Invertebrate assemblages recovered rapidly in these streams despite the large areal extent of the fire. However, the frequency of wildfires is increasing, potentially permanently altering riparian vegetation structure and composition. As headwater streams depend on riparian vegetation for shading, woody debris and leaf litter, such permanent changes will likely affect biodiversity in headwater streams.
      PubDate: 2018-02-23
      DOI: 10.1007/s00027-018-0570-7
      Issue No: Vol. 80, No. 2 (2018)
       
  • Changes in dissolved organic matter and microbial activity in runoff
           waters of boreal mires after restoration
    • Authors: Noora Räsänen; Paula Kankaala; Teemu Tahvanainen; Jarkko Akkanen; Sanna Saarnio
      Abstract: A considerable proportion of boreal mires have been drained for soil amelioration purposes. In response to drainage-induced degradation, restoration practices have been implemented in recent decades. Restoration by raising the water level is often followed by changes in the quality of runoff waters, especially in concentrations of dissolved organic carbon (DOC), nitrogen (N) and phosphorus (total P, PO4-P). We studied how mire restoration affected bacterial production (BP), bacterial growth efficiency (BGE%) and respiration (R) in mire runoff waters from spruce swamps and Sphagnum pine bogs in south-central Finland. The quality of runoff water was monitored for 8 years (2008–2015) and bacterial activity was measured during 3 years (2010–2012) at runoff weir sites, including two pristine controls, one drained control and four treatment sites. The concentrations of DOC, N and P increased for 3–5 years after restoration. The increased availability of nutrients was followed by doubled BP (from ca. 0.34 to 0.88 µmol C L−1 d−1, averages of restored sites) and BGE% (from ca. 2.7 to 9.2%), whereas microbial respiration was only slightly increased. However, bacterial activity in mire waters was low compared with those generally measured in river and lake waters. This was presumably related to the recalcitrant quality of the mire-originated DOC, which was not clearly influenced by restoration. Dissolved organic matter (DOM) of low bioavailability contributes to browning of headwaters. As our study was focused only on short-term (1–5 years) effects, more research is needed for evaluating long-term impacts of peatland origin DOM on carbon fluxes, microbial activity and food webs of recipient aquatic ecosystems.
      PubDate: 2018-02-23
      DOI: 10.1007/s00027-018-0569-0
      Issue No: Vol. 80, No. 2 (2018)
       
  • Seasonal and inter-annual variations in carbon fluxes in a tropical river
           system (Tana River, Kenya)
    • Authors: Naomi Geeraert; Fred O. Omengo; Fredrick Tamooh; Trent R. Marwick; Alberto V. Borges; Gerard Govers; Steven Bouillon
      Abstract: The hydrological status of river systems is expected to change due to dam operations and climate change. This will affect the riverine fluxes of sediment and carbon (C). In rivers with strong seasonal and inter-annual variability, quantification and extrapolation of sediment and C fluxes can be a challenge as measurement periods are often too short to cover all hydrological conditions. We studied the dynamics of the Tana River (Kenya) from 2012 to 2014 through daily monitoring of sediment concentrations at three sites (Garissa, Tana River Primate Reserve and Garsen) and daily monitoring of C concentrations in Garissa and Garsen during three distinct seasons. A bootstrap method was applied to calculate the range of sediment and C fluxes as a function of annual discharge by using daily discharge data (1942–2014). Overall, we estimated that on average, sediment and carbon were retained in this 600 km long river section between Garissa to Garsen over the 73 years (i.e., fluxes were higher at the upstream site than downstream): integration over all simulations resulted in an average net retention of sediment (~ 2.9 Mt year− 1), POC (~ 18,000 tC year− 1), DOC (~ 920 tC year− 1) and DIC (~ 1200 tC year− 1). To assess the impact of hydrological variations, we constructed four different hydrological scenarios over the same period. Although there was significant non-linearity and difference between the C species, our estimates generally predicted a net increase of C retention between the upstream and downstream site when the annual discharge would decrease, for example caused by an increase of irrigation with reservoir water. When simulating an increase in the annual discharge, e.g. as a potential effect of climate change, we predicted a decrease in C retention.
      PubDate: 2018-02-22
      DOI: 10.1007/s00027-018-0573-4
      Issue No: Vol. 80, No. 2 (2018)
       
  • Beta-diversity partitioning and drivers of variations in tropical fish
           community structure in central India
    • Authors: Rohitashva Shukla; Anuradha Bhat
      Abstract: Flow regulations, human activities and drying events have been shown to drive diversity patterns of stream fish communities globally. Along with alpha-diversity distributions across space and time, study of beta-diversity patterns provides a deeper understanding of the mechanisms and processes of overall diversity distributions. It has been shown that water flow conditions can determine the beta-diversity patterns in stream fish communities: in general, perennial habitats are more similar, while intermittent and regulated conditions tend to increase dissimilarities among sites. However, it is not clear whether these patterns result from changes in abundance replacement or from differences in species abundance. Here, we investigated beta-diversity patterns in tropical fish communities of central India and their relation to habitat structural properties and water conditions. We performed our analysis for the overall region (18 sites) and also across three distinct flow conditions (6 sites for each flow regime). We used a partitioning framework to uncover the contribution of abundance replacement and abundance difference to beta-diversity patterns for the overall region and for three flow conditions separately. Our results suggest that at a regional scale all the sites show an equal contribution of replacement and abundance difference components, while seasonal samples were homogeneous. Our results confirmed that intermittent and regulated sites are more heterogeneous than perennial sites. The observed changes in beta-diversity in intermittent and regulated sites were related to both abundance difference and replacement components. Dissimilarities between sites were explained by physicochemical (temperature, pH, dissolved oxygen) parameters but not by habitat structural (stream width, depth) parameters.
      PubDate: 2018-02-21
      DOI: 10.1007/s00027-018-0568-1
      Issue No: Vol. 80, No. 2 (2018)
       
  • Variance partitioning of deconstructed tropical diatom communities in
           reservoirs cascade
    • Authors: Gisele C. Marquardt; André Andrian Padial; Carlos E. de M. Bicudo
      Abstract: We used variation partitioning to evaluate significance of local environment, spatial structure and hydrological connectivity in the diatom community variation in phytoplankton and superficial sediments of six reservoirs of southeast Brazil. Common and rare diatom species were represented by different data sets, according to the species relative abundance and frequency of occurrence. To clarify the connectivity effect on the metacommunity organization, analyses were performed with and without a hydrological connectivity matrix as predictor. Results for rare and common species were similar, but explanation power depended on the habitat and the climatic season. The hydrological connectivity predictor proved to play an important role toward explaining the diatom metacommunity dynamics. Consequently, this landscape feature should not be neglected in ecological models of managed rivers.
      PubDate: 2018-02-21
      DOI: 10.1007/s00027-018-0571-6
      Issue No: Vol. 80, No. 2 (2018)
       
  • Factors affecting the metacommunity structure of periphytic ostracods
           (Crustacea, Ostracoda): a deconstruction approach based on biological
           traits
    • Authors: Ramiro de Campos; Fernando Miranda Lansac-Tôha; Eliezer de Oliveira da Conceição; Koen Martens; Janet Higuti
      Abstract: Metacommunity studies using the deconstruction approach based on biological traits have received a great deal of attention in recent years as they often better describe characteristics of the species that reflect adaptations to a specific environment. This approach has not yet been used for ostracods, which are nevertheless highly diverse crustaceans and abundant in continental aquatic environments. Here, we investigate the influence of environmental and spatial factors on the metacommunity structure of periphytic ostracods in 27 tropical floodplain lakes in the Upper Paraná River floodplain (Brazil). An analysis of variance partitioning was used to estimate the relative importance of these factors (environmental and spatial) on both the entire community as well as after its deconstruction according to the biological traits (size and locomotion mode). Ostracods, regardless of body size, are good dispersers at regional scales. In addition, as expected, swimming ostracods were better dispersers at local scales than non-swimmers, which were influenced mainly by the diversity of aquatic macrophytes. Environmental factors (species sorting mechanism) seem important in structuring the entire ostracods metacommunity, as well as for most categories of biological traits. The unexplained variability remained high showing that other variables, not measured here, must be important. The analysis based on deconstruction, when compared to the analysis based on the metacommunity as a whole, contributed to a better assessment of ostracod metacommunity structuring.
      PubDate: 2018-02-07
      DOI: 10.1007/s00027-018-0567-2
      Issue No: Vol. 80, No. 2 (2018)
       
  • Species traits reveal effects of land use, season and habitat on the
           potential subsidy of stream invertebrates to terrestrial food webs
    • Authors: B. G. McKie; L. Sandin; P. E. Carlson; R. K. Johnson
      Abstract: Adult aquatic insects with a terrestrial life-stage are important vectors transferring resources assimilated in freshwater environments to terrestrial consumers. Research on this linkage has focused particularly on how terrestrial environmental features affect dispersal of adult aquatic insects, and on the responses of terrestrial consumers. However, both the timing and extent of dispersal by adult aquatic insects are further regulated by their species-specific life history traits. We sampled aquatic invertebrates from nine streams in central Sweden, and assessed how the composition of key traits related to dispersal and life history varied between in-stream habitats (riffles, pools), seasons (autumn, spring), and among streams differing in catchment land use (forested, agriculture). Traits indicative of more limited adult dispersal (e.g. small adult size and weak flying strength), along with traits indicative of strongly pulsed peaks in emergence (e.g. univoltinism and well-synchronised emergence) were all more abundant in the agricultural than forested streams in the autumn. However, these differences had disappeared by late spring, possibly reflecting early emergence by the univoltine taxa that dominated the agricultural stream communities and/or elevated mortality in the agricultural streams. Riffles supported higher abundances of insects with strongly flying adults, whereas traits associated with more limited dispersal were characteristic of insect assemblages in pools, which also supported the highest proportion of invertebrates completely lacking an adult flying stage. This result is likely to have implications at larger scales, given the dominance of soft-bottomed pool habitats and scarcity of riffles in many agricultural landscapes. Overall, our analysis indicates that while overall production of aquatic invertebrates with a winged adult was greater in agricultural streams, availability of this productivity for terrestrial consumers is more likely to be spatially restricted closer to the stream channel, and potentially also more temporally pulsed .
      PubDate: 2018-01-19
      DOI: 10.1007/s00027-018-0565-4
      Issue No: Vol. 80, No. 2 (2018)
       
  • Tank bromeliads sustain high secondary production in neotropical forests
    • Authors: Olivier Dézerald; Céline Leroy; Bruno Corbara; Alain Dejean; Stanislas Talaga; Régis Céréghino
      Abstract: In neotropical landscapes, a substantial fraction of the still waters available is found within tank bromeliads, plants which hold a few milliliters to several litres of rainwater within their leaf axils. The bromeliad ecosystem is integrated into the functioning of rainforest environments, but no study has ever estimated the secondary production, nor the biomass turnover rates of bromeliad macroinvertebrates in relation to other functional traits. We estimated secondary production at invertebrate population to metacommunity level in bromeliads of French Guiana. Coleoptera, Diptera and Crustacea with traits that confer resistance to drought had lower biomass turnover, longer generation times, and slower individual growth than species without particular resistance traits, suggesting convergent life history strategies in phylogenetically distant species. Detritivores and predators accounted for 87% and 13% of the overall annual production, respectively, but had similar production to biomass ratios. An average bromeliad sustained a production of 23.93 g dry mass m−2 year−1, a value which exceeds the medians of 5.0–14.8 g DM m−2 year−1 for lakes and rivers worldwide. Extrapolations to the total water volumes held by bromeliads at our field site yielded secondary production estimates of 226.8 ± 32.5 g DM ha−1 year−1. We conclude that the ecological role of tank bromeliads in neotropical rainforests may be as important as that of other freshwater ecosystems.
      PubDate: 2018-01-17
      DOI: 10.1007/s00027-018-0566-3
      Issue No: Vol. 80, No. 2 (2018)
       
  • Observations on the dynamics and fate of dissolved organic phosphorus in
           lake water and a new model of eplimnetic P cycling
    • Authors: William D. Taylor; David R. S. Lean
      Abstract: Phosphorus (P) in lake water is commonly partitioned into particulate P and dissolved P by membrane filtration, and dissolved P is then fractionated into soluble reactive P (SRP, reactive with molybdate) and dissolved unreactive or organic P (DOP). Much of what is known about DOP is derived from radiotracer studies using gel chromatography, and summarized by a kinetic model (Lean, Science 179:678–680, 1973a; Lean, J Fish Res Board Can 30:1525–1536, 1973b). Since this work, several relevant discoveries have been made on the role of enzymes, viruses and zooplankton in regenerating dissolved P, and the role of filtration damage in generating dissolved P in filtrates. Herein we present the results of new radiotracer experiments on the fate of DOP in lake water filtrates, consistent with the hypothesis that some of the high molecular weight organic P breaks down spontaneously to smaller molecules, which in turn break down to PO43−. We use inhibitors, including competitive inhibitors of phosphatases and a commercial product (RNA-later®) to support the hypothesis that the larger molecules include nucleic acids, and that the smaller molecules are substrates for alkaline phosphatase. We also find that colloidal P (i.e., P > 5000 MW according to gel filtration) includes some virus-sized material that can be collected on 0.02 or 0.03 µm filters. Finally, we provide a new model of the cycling of epilimnetic P that is consistent with these and earlier observations.
      PubDate: 2018-01-16
      DOI: 10.1007/s00027-018-0564-5
      Issue No: Vol. 80, No. 2 (2018)
       
  • Effects of turbulence exposure on zebra mussel ( Dreissena polymorpha )
           larval survival
    • Authors: J. L. Kozarek; M. Hondzo; M. E. Kjelland; C. D. Piercy; T. M. Swannack
      Abstract: To more accurately predict recruitment of zebra mussels (Dreissena polymorpha) in waterbodies downstream of a source population, factors that control the successful transport of zebra mussel larvae need to be quantified. Turbulence has been identified in previous studies as a likely factor in larval morality in rivers and streams where turbulent energy dissipation can be orders of magnitude greater than in lakes. To investigate the impact of turbulent energy dissipation on zebra mussel larval mortality, we conducted a series of experiments using lake water collected from Lake Minnetonka, Minnesota containing veligers in a jar test device. Results indicate that zebra mussel larval mortality is a function of veliger size, turbulent energy dissipation, and exposure time. The mortality at 24 h of turbulence exposure was fit to a function of d*, the ratio of shell size to Kolmogorov length scale, to develop a dose–response curve. Mortality rate constants were estimated by fitting mortality data from specified turbulence regimes to a first-order model. The mortality rates ranged from 0.09 to 1.71 day−1 and were correlated to energy dissipation.
      PubDate: 2018-01-05
      DOI: 10.1007/s00027-017-0563-y
      Issue No: Vol. 80, No. 1 (2018)
       
  • Open-channel measurement of denitrification in a large lowland river
    • Authors: Stephanie Ritz; Kirstin Dähnke; Helmut Fischer
      Abstract: Denitrification is considered to be the most important pathway removing nitrogen from terrestrial and freshwater ecosystems. However, field studies that quantify this process under in situ conditions are sparse, especially in large rivers. Here, we measured N2, the end product of denitrification, directly in the water column of a large 8th order lowland river (Elbe, Germany) using N2/Ar ratios measured by Membrane Inlet Mass Spectrometry (MIMS). Denitrification was calculated according to the open-channel two-station approach based on Lagrangian sampling along a 580 km long, mostly free flowing river section. Gas exchange was computed by several empirical equations to bound uncertainty in air–water exchange and the resulting fluxes were used to estimate ranges in N2-production. In summer 2011 and spring 2012, we found slight but distinct N2 super saturations in the river water averaging 2.8 and 3.5 µM, respectively. Denitrification rates averaged 18 and 13 mg N m− 2 h− 1 for summer 2011 and spring 2012, respectively. On an annual cycle this corresponds to a nitrogen removal of 10,000 t N year− 1 that is 10% of the total N inputs along the studied river section. These results show that large rivers can remove large amounts of nitrogen during downstream transport and demonstrate that the open-channel N2 method provides a valuable tool to study in situ denitrification not only in small, but also in large rivers.
      PubDate: 2017-12-20
      DOI: 10.1007/s00027-017-0560-1
      Issue No: Vol. 80, No. 1 (2017)
       
  • Fate of juvenile salmonids stranded in off-channel pools: implications for
           nutrient transfers
    • Authors: Richard H. Walker; Bryan M. Maitland; Tayler N. LaSharr; Michael N. Rosing; Merav Ben-David
      Abstract: Fish stranding is a complex phenomenon largely attributed to anthropogenic causes in regulated rivers. Although our knowledge of the frequency of stranding and fate of stranded fish in unregulated rivers is limited, this phenomenon may be widespread and important for the transfer of nutrients from aquatic to terrestrial ecosystems. Using a combination of observational data, an experimental manipulation, and a nitrogen subsidy model, we investigated the fate and implications of fish stranded in off-channel pools created by the last spring flood, in the Kadashan River watershed on Chichagof Island, Alaska, USA. Of fish stranded in pools (exclusively juvenile Dolly Varden Char [Salvelinus malma] and Coho Salmon [Oncorhynchus kisutch]), smaller individuals (age-0; < 74 mm) were more common than larger ones (age-1; > 74 mm). Mortality rate was mainly influenced by cover availability, and larger fish tended to disappear at a higher rate than smaller ones. These observations, together with detection of predator activity, suggest that predation was the main cause of mortality for stranded fish. We estimate that fish stranding occurred during 66% of the years between 1980 and 2015, and that in a single stranding event approximately 1.62 kg of nitrogen is available to predators in the 0.24 km2 floodplain of the Kadashan watershed surveyed. Thus, fish stranding likely has implications for cross ecosystem connectivity via aquatic nutrient transfers to terrestrial food webs. With projected increases in extreme precipitation and flood events in Southeast Alaska the incidence of fish stranding in unregulated rivers will likely increase. Our results suggest by ensuring that cover (e.g. large wood and artificial structures) is available in off-channel habitats to benefit species or populations of conservation concern.
      PubDate: 2017-12-14
      DOI: 10.1007/s00027-017-0562-z
      Issue No: Vol. 80, No. 1 (2017)
       
  • Effects of inundation and stranding on leaf litter decomposition and
           chemical transformation
    • Authors: Junqiang Zheng; Yuzhe Wang; Chengrong Chen; Qi Jiang; Shijie Han; Zhihong Xu
      Abstract: Inundation and stranding are important processes of the riparian ecosystem due to water level fluctuation. Plant litter decomposition is a key process that determines the accumulation of soil organic matter in riparian ecosystems, but little is known about the alternating effects of inundation and stranding on this process. Using litters of the grass species Heteropogon contortus, we studied how the remaining mass and nitrogen (N), δ13C and δ15N, and 13C-CPMAS NMR spectra responded to permanent inundation, temporary inundation and drying over a period of twelve months. Inundation (permanent or temporary) and stranding altered litter C and N dynamics. The δ13C declined in the immersed litters and was stable after the litters were transported to the grassland plots, while δ15N in the litters that were decomposing continually in the water rapidly increased during the earlier stage of decomposition. We observed a significant increase in the proportion of ketone, carboxyl, and alkyl in the permanently inundated litter samples compared with those of litters decomposed at terrestrial habitats at the final harvest. These results indicated that the effects of inundation on the decay of labile and recalcitrant litter components were asynchronous. The decomposing litters in the inundation treatment differed chemically from those in the terrestrial habitat treatments and were characterized by greater relative abundances of ketone C and carboxyl C. The higher values of alkyl/O-alkyl for the stranding litters that had higher mass remaining and C/N as compared to those of inundated litters that had lower mass remaining and C/N in the final harvest, suggested a relatively higher contribution of the recalcitrant components to the litter residues. Likewise, the effects of transient inundation depend on the timing of immersion and stranding.
      PubDate: 2017-12-04
      DOI: 10.1007/s00027-017-0561-0
      Issue No: Vol. 80, No. 1 (2017)
       
 
 
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