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Madge Pimentel I, Baikova D, Buchner D, Burfeid Castellanos A, David GM, Deep A, Doliwa A, Hadžiomerović U, Mayombo NAS, Prati S, Spyra MA, Vermiert AM, Beisser D, Dunthorn M, Piggott JJ, Sures B, Tiegs SD, Leese F, Beermann AJ. Assessing the response of an urban stream ecosystem to salinization under different flow regimes. Sci Total Environ 2024; 926:171849. [PMID: 38537828 DOI: 10.1016/j.scitotenv.2024.171849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/08/2024] [Accepted: 03/19/2024] [Indexed: 04/07/2024]
Abstract
Urban streams are exposed to a variety of anthropogenic stressors. Freshwater salinization is a key stressor in these ecosystems that is predicted to be further exacerbated by climate change, which causes simultaneous changes in flow parameters, potentially resulting in non-additive effects on aquatic ecosystems. However, the effects of salinization and flow velocity on urban streams are still poorly understood as multiple-stressor experiments are often conducted at pristine rather than urban sites. Therefore, we conducted a mesocosm experiment at the Boye River, a recently restored stream located in a highly urbanized area in Western Germany, and applied recurrent pulses of salinity along a gradient (NaCl, 9 h daily of +0 to +2.5 mS/cm) in combination with normal and reduced current velocities (20 cm/s vs. 10 cm/s). Using a comprehensive assessment across multiple organism groups (macroinvertebrates, eukaryotic algae, fungi, parasites) and ecosystem functions (primary production, organic-matter decomposition), we show that flow velocity reduction has a pervasive impact, causing community shifts for almost all assessed organism groups (except fungi) and inhibiting organic-matter decomposition. Salinization affected only dynamic components of community assembly by enhancing invertebrate emigration via drift and reducing fungal reproduction. We caution that the comparatively small impact of salt in our study can be due to legacy effects from past salt pollution by coal mining activities >30 years ago. Nevertheless, our results suggest that urban stream management should prioritize the continuity of a minimum discharge to maintain ecosystem integrity. Our study exemplifies a holistic approach for the assessment of multiple-stressor impacts on streams, which is needed to inform the establishment of a salinity threshold above which mitigation actions must be taken.
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Affiliation(s)
- Iris Madge Pimentel
- Aquatic Ecosystem Research, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.
| | - Daria Baikova
- Aquatic Microbiology, Environmental Microbiology and Biotechnology, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany
| | - Dominik Buchner
- Aquatic Ecosystem Research, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | | | - Gwendoline M David
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Department of Plankton and Microbial Ecology, Stechlin, Germany
| | - Aman Deep
- Biodiversity, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Annemie Doliwa
- Aquatic Ecology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany
| | - Una Hadžiomerović
- Aquatic Microbiology, Environmental Microbiology and Biotechnology, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany
| | | | - Sebastian Prati
- Aquatic Ecology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany
| | | | - Anna-Maria Vermiert
- Ruhr University Bochum, Department of Animal Ecology, Evolution and Biodiversity, Bochum, Germany
| | - Daniela Beisser
- Department of Engineering and Natural Sciences, Westphalian University of Applied Sciences, Recklinghausen, Germany
| | - Micah Dunthorn
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Jeremy J Piggott
- Zoology and Trinity Centre for the Environment, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland
| | - Bernd Sures
- Aquatic Ecology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany; Research Center One Health Ruhr of the University Alliance Ruhr, University of Duisburg-Essen, Essen, Germany
| | - Scott D Tiegs
- Department of Biological Sciences, Oakland University, Rochester, MI, USA
| | - Florian Leese
- Aquatic Ecosystem Research, Faculty of Biology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany
| | - Arne J Beermann
- Aquatic Ecosystem Research, Faculty of Biology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany
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