18 results match your criteria Aquatic Sciences[Journal]

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Community stability and seasonal biotic homogenisation emphasize the effect of the invasive tropical tanner grass on macrophytes from a highly dynamic neotropical tidal river.

Aquat Sci 2022 5;84(2):30. Epub 2022 Apr 5.

Laboratório de Análise e Síntese em Biodiversidade, Departamento de Botânica, Setor de Ciências Biológicas, Universidade Federal do Paraná, Curitiba, PR Brazil.

We described the spatial and temporal dynamics of aquatic macrophytes in a Neotropical coastal estuarine river, and identified the negative effects associated to the presence and dominance of the invasive tanner grass. We compared macrophyte beds along the Guaraguaçu River (South Brazil) over four years, using taxonomic and functional dimensions. Biodiversity descriptors were higher in the driest periods compared to the rainiest, although this difference seems to be decreasing over the studied years. Read More

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Effects of space and environment on phytoplankton distribution in subtropical reservoirs depend on functional features of the species.

Aquat Sci 2022 27;84(1). Epub 2021 Nov 27.

Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais-PEA, Universidade Estadual de Maringá-UEM, Maringá, PR Brazil.

Environmental factors and dispersal can influence the structure of biological communities. Their effects can depend on the functional features of the species in the community. Since species belonging to the same trophic level, such as phytoplankton, may show functional differences, we investigated whether the effects of environment and dispersal differ among phytoplankton species from different functional groups. Read More

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November 2021

Continental-scale effects of phytoplankton and non-phytoplankton turbidity on macrophyte occurrence in shallow lakes.

Authors:
Lester L Yuan

Aquat Sci 2021 ;14

Office of Water, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave, NW (MC 4304T), Washington, DC 20460.

Submerged macrophytes are key components of shallow lake biological communities, and their presence has been associated with a predominantly clear-water state. Conversely, lakes lacking macrophytes are often turbid with elevated phytoplankton abundance. One main mechanism that influences the presence or absence of submerged macrophytes is turbidity that reduces the light available to macrophytes. Read More

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January 2021

Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data.

Aquat Sci 2021 10;83(2):37. Epub 2021 Mar 10.

Eawag, Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland.

Freshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, however, it is unclear what the main controlling factors are. Here, we investigated the factors that moderate the rates of N removal under contrasting trophic states in two lakes located in central Switzerland. Read More

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Resilience of aquatic systems: Review and management implications.

Aquat Sci 2020 Mar;82(2):1-44

Office of Research and Development, Center for Environmental Measurement and Modeling, Watershed and Ecosystem Characterization Division, U.S. Environmental Protection Agency, Cincinnati, OH, USA.

Our understanding of how ecosystems function has changed from an equilibria-based view to one that recognizes the dynamic, fluctuating, nonlinear nature of aquatic systems. This current understanding requires that we manage systems for resilience. In this review, we examine how resilience has been defined, measured and applied in aquatic systems, and more broadly, in the socioecological systems in which they are embedded. Read More

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CH oxidation in a boreal lake during the development of hypolimnetic hypoxia.

Aquat Sci 2020 28;82(2):19. Epub 2019 Dec 28.

1Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, 70210 Kuopio, Finland.

Freshwater ecosystems represent a significant natural source of methane (CH). CH produced through anaerobic decomposition of organic matter (OM) in lake sediment and water column can be either oxidized to carbon dioxide (CO) by methanotrophic microbes or emitted to the atmosphere. While the role of CH oxidation as a CH sink is widely accepted, neither the magnitude nor the drivers behind CH oxidation are well constrained. Read More

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December 2019

Bacterial community composition and function along spatiotemporal connectivity gradients in the Danube floodplain (Vienna, Austria).

Aquat Sci 2020 18;82(2):28. Epub 2020 Feb 18.

1Department of Limnology and Oceanography, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.

It is well recognized that river-floodplain systems contribute significantly to riverine ecosystem metabolism, and that bacteria are key players in the aquatic organic carbon cycle, but surprisingly few studies have linked bacterial community composition (BCC), function and carbon quality in these hydrologically highly dynamic habitats. We investigated aquatic BCC and extracellular enzymatic activity (EEA) related to dissolved organic carbon quality and algae composition, including the impact of a major flood event in one of the last remaining European semi-natural floodplain-systems. We found that surface connectivity of floodplain pools homogenizes BCC and EEA, whereas low connectivity led to increased BCC and EEA heterogeneity, supported by their relationship to electrical conductivity, an excellent indicator for surface connection strength. Read More

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February 2020

Importance of mixotrophic flagellates during the ice-free season in lakes located along an elevational gradient.

Aquat Sci 2019 16;81(3):45. Epub 2019 Apr 16.

1Department of Ecology, Lake and Glacier Research Group, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria.

Mixotrophy seems to be widespread among phytoplankton, but whether this strategy is more relevant in oligotrophic lakes remains unclear. Here, we tested the hypothesis that the relative abundance of mixotrophic flagellates in lakes increases along an elevational gradient paralleling increasingly oligotrophic conditions. For this purpose, 12 lakes located between 575 and 2796 m above sea level were sampled in summer and fall to include two different seasonal windows in phytoplankton dynamics and environmental conditions. Read More

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Longitudinal thermal heterogeneity in rivers and refugia for coldwater species: effects of scale and climate change.

Aquat Sci 2018 Jan;80(3):1-15

Climate Impacts Group, University of Washington, Seattle, WA, USA.

Climate-change driven increases in water temperature pose challenges for aquatic organisms. Predictions of impacts typically do not account for fine-grained spatiotemporal thermal patterns in rivers. Patches of cooler water could serve as refuges for anadromous species like salmon that migrate during summer. Read More

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January 2018

Invasive crayfish impacts on native fish diet and growth vary with fish life stage.

Aquat Sci 2017 22;79(1):113-125. Epub 2016 Apr 22.

1School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS UK.

Assessing the impacts of invasive organisms is a major challenge in ecology. Some widespread invasive species such as crayfish are potential competitors and reciprocal predators of ecologically and recreationally important native fish species. Here, we examine the effects of signal crayfish () on the growth, diet, and trophic position of the chub () in four rivers in Britain. Read More

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Long-term evolution of fish communities in European mountainous rivers: past log driving effects, river management and species introduction (Salzach River, Danube).

Aquat Sci 2015;77(3):395-410. Epub 2015 Jun 5.

Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences Vienna, Max Emanuelstrasse 17, 1180 Vienna, Austria.

Using historical sources from the turn of the 19th to the 20th century, we investigated the long-term evolution of the fish community in a mountainous river network and the influence of different human uses and management measures. Within the alpine Salzach catchment, historical presence was reconstructed for 26 fish species, abundance classes for 19 species. Due to channelization, flood protection and dam erections, the spatial distribution of fish species was reduced during the 20th century. Read More

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Historical ecology of riverine fish in Europe.

Aquat Sci 2015;77(3):315-324. Epub 2015 Jul 7.

Faculty of Interdisciplinary Studies, Institute of Social Ecology, Alpen-Adria-Universität Klagenfurt, Schottenfeldgasse 29, 1070 Vienna, Austria.

The temporal dynamic of riverine ecosystems and their fish communities and populations has been addressed in ecological theory and management for several decades. A growing number of case studies on the historic development especially of European and North American rivers have been published. Nonetheless, a theoretical debate about the contributions and limits of historical approaches and interdisciplinary co-operation is lacking. Read More

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Historical change in fish species distribution: shifting reference conditions and global warming effects.

Aquat Sci 2015;77(3):441-453. Epub 2015 Jan 3.

Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences Vienna, Max-Emanuel-Strasse 17, 1180 Vienna, Austria.

Species distributions models (SDM) that rely on estimated relationships between present environmental conditions and species presence-absence are widely used to forecast changes of species distributions caused by global warming but far less to reconstruct historical assemblages. By compiling historical fish data from the turn to the middle of the twentieth century in a similar way for several European catchments (Rhône, Danube), and using already published SDMs based on current observations, we: (1) tested the predictive accuracy of such models for past climatic conditions, (2) compared observed and expected cumulated historical species occurrences at sub-catchment level, and (3) compared the annual variability in the predictions within one sub-catchment (Salzach) under a future climate scenario to the long-term variability of occurrences reconstructed during an extended historical period (1800-2000). We finally discuss the potential of these SDMs to define a "reference condition", the possibility of a shift in baseline condition in relation with anthropogenic pressures, and past and future climate variability. Read More

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January 2015

Fish remains as a source to reconstruct long-term changes of fish communities in the Austrian and Hungarian Danube.

Aquat Sci 2015;77(3):337-354. Epub 2015 Jun 3.

Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria.

The main objective of this paper is to investigate how archaeological fish remains and written historical records can contribute to the reconstruction of long-term developments of fish communities along the Austrian and Hungarian Danube. Although such approaches are sensitive to various factors, the chronological subdivision and relative quantification of proxy data demonstrate environmental and faunal changes from Prehistory onwards. Intensification of fisheries, decline of large specimens and massive exploitation of small and young fish point to increasing pressure along the chronological sequence towards Early Modern times. Read More

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Origin, enzymatic response and fate of dissolved organic matter during flood and non-flood conditions in a river-floodplain system of the Danube (Austria).

Aquat Sci 2014 22;76:115-129. Epub 2013 Oct 22.

Department of Limnology and Oceanography, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.

Spectroscopic techniques and extracellular enzyme activity measurements were combined with assessments of bacterial secondary production (BSP) to elucidate flood-pulse-linked differences in carbon (C) sources and related microbial processes in a river-floodplain system near Vienna (Austria). Surface connection with the main channel significantly influenced the quantity and quality of dissolved organic matter (DOM) in floodplain backwaters. The highest values of dissolved organic carbon (DOC) and chromophoric DOM (CDOM) were observed during the peak of the flood, when DOC increased from 1. Read More

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October 2013

Cumulative effects of land use on fish metrics in different types of running waters in Austria.

Aquat Sci 2012;74(2):329-341. Epub 2011 Aug 5.

Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU, University of Natural Resources and Life Sciences, Max Emanuel-Strasse 17, 1180 Vienna, Austria.

The catchment land-use composition of 249 fish sampling sites in Austrian running waters revealed effects on the biological integrity. Beyond correlative analysis, we investigated (1) which land-use category had the strongest effect on fish, (2) whether metrics of functional fish guilds reacted differently, (3) whether there were cumulative effects of land-use categories, and (4) whether effects varied in strength across river types. We fed 5 land-use categories into regression trees to predict the European Fish Index or fish metric of intolerant species (mainly ) Agriculture and urbanisation were the best predictors and indicated significant effects at levels of >23. Read More

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Year-round variability of ambient noise in temperate freshwater habitats and its implications for fishes.

Aquat Sci 2010 Jun;72(3):371-378

Department of Behavioural Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria,

Changes in habitat acoustics over the year can potentially affect fish hearing and orientation to sound, especially in temperate climates. This is the first study where year-round changes in ambient noise in aquatic habitats were assessed. Seven different European fresh-water habitats were chosen for this study. Read More

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Viruses, bacteria and suspended particles in a backwater and main channel site of the Danube (Austria).

Aquat Sci 2008 May;70(2):186-194

University of Vienna, Department of Freshwater Ecology, Althanstrasse 14, 1090 Vienna, Austria.

A short overview of currently available studies on the ecology of viruses in running waters is provided. Additionally, a survey was conducted on the dynamics of both viruses and bacteria in an isolated floodplain segment of the Danube River and in the main channel near Vienna (Austria) during the hydrologically most dynamic phase (spring - summer). The study evaluates the differences between the main channel and the floodplain segment for suspended particle abundance and quality in relation to bacterial and viral parameters; both free-living forms and those attached to particles are examined. Read More

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