Andersson, Matilda
- Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Abstract
Freshwater ecosystems are affected by fluctuations in terrestrially derived dissolved organic carbon (DOC). Increased DOC runoff from watersheds can contribute to the "browning" of freshwater systems, altering water properties and disrupting food web dynamics, with potential impacts on fish. This study examined how carbon sources and the trophic ecology of temperate freshwater fishes varied with DOC concentrations. We used stable isotope ratios of carbon (delta 13C) and nitrogen (delta 15N) to trace carbon sources in organisms at low trophic levels and to assess the trophic ecology of six fish species from 70 lakes in Sweden, Germany, Canada, and the United States. We found that both pelagic and benthic delta 13C decreased as DOC increased, suggesting higher reliance on terrestrial carbon by lower trophic level organisms. Fish responses to elevated DOC were limited to certain species. Mid-trophic level European perch (Perca fluviatilis) increased pelagic diet proportions, while top predators like northern pike (Esox Lucius) and walleye (Sander vitreus) showed nonlinear shifts. Except for walleye, no effect of DOC was detected on fish trophic position. Our findings suggest that DOC alters energy use and diet but not trophic position in some freshwater fish.
Keywords
freshwater ecosystems; food web dynamics; fish; interspecific variation; stable isotope analysis; browning
Published in
Canadian Journal of Fisheries and Aquatic Sciences
2025, volume: 82, article number: 0343
Publisher: CANADIAN SCIENCE PUBLISHING
SLU Authors
Chaguaceda, Fernando
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Van Dorst, Renee
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
UKÄ Subject classification
Fish and Aquacultural Science
Publication identifier
- DOI: https://doi.org/10.1139/cjfas-2024-0343
Permanent link to this page (URI)
https://res.slu.se/id/publ/144509