Global change‐driven effects on dissolved organic matter composition: Implications for food webs of northern lakes |
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| Authors: | Irena F Creed Ann‐Kristin Bergström Charles G Trick Nancy B Grimm Dag O Hessen Jan Karlsson Karen A Kidd Emma Kritzberg Diane M McKnight Erika C Freeman Oscar E Senar Agneta Andersson Jenny Ask Martin Berggren Mehdi Cherif Reiner Giesler Erin R Hotchkiss Pirkko Kortelainen Monica M Palta Tobias Vrede Gesa A Weyhenmeyer |
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| Affiliation: | 1. School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada;2. Department of Ecology and Environmental Science, Ume? University, Ume?, Sweden;3. Interfaculty Program on Public Health & Department of Biology, Western University, London, ON, Canada;4. School of Life Sciences, Arizona State University, Tempe, AZ, USA;5. Section 6. for Aquatic Biology and Toxicology, University of Oslo, Oslo, Norway;7. Climate Impacts Research Centre, Department of Ecology and Environmental Science, Ume? University, Ume?, Sweden;8. Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, NB, Canada;9. Department of Biology, Lund University, Lund, Sweden;10. INSTAAR, University of Colorado, Boulder, CO, USA;11. Department of Geography, Western University, London, ON, Canada;12. Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden;13. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA;14. Finnish Environment Institute, Helsinki, Finland;15. Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden;16. Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden |
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| Abstract: | Northern ecosystems are experiencing some of the most dramatic impacts of global change on Earth. Rising temperatures, hydrological intensification, changes in atmospheric acid deposition and associated acidification recovery, and changes in vegetative cover are resulting in fundamental changes in terrestrial–aquatic biogeochemical linkages. The effects of global change are readily observed in alterations in the supply of dissolved organic matter (DOM)—the messenger between terrestrial and lake ecosystems—with potentially profound effects on the structure and function of lakes. Northern terrestrial ecosystems contain substantial stores of organic matter and filter or funnel DOM, affecting the timing and magnitude of DOM delivery to surface waters. This terrestrial DOM is processed in streams, rivers, and lakes, ultimately shifting its composition, stoichiometry, and bioavailability. Here, we explore the potential consequences of these global change‐driven effects for lake food webs at northern latitudes. Notably, we provide evidence that increased allochthonous DOM supply to lakes is overwhelming increased autochthonous DOM supply that potentially results from earlier ice‐out and a longer growing season. Furthermore, we assess the potential implications of this shift for the nutritional quality of autotrophs in terms of their stoichiometry, fatty acid composition, toxin production, and methylmercury concentration, and therefore, contaminant transfer through the food web. We conclude that global change in northern regions leads not only to reduced primary productivity but also to nutritionally poorer lake food webs, with discernible consequences for the trophic web to fish and humans. |
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| Keywords: | atmospheric change cyanobacteria dissolved organic matter food webs lake mercury northern |
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