2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/23/2018 | 10:00 AM - 10:15 AM | THE FATE OF TERRESTRIALLY DERIVED DISSOLVED ORGANIC MATTER IN ONE SUB-TROPICAL AND THREE TEMPERATE LAKES OF VARYING TROPHIC STATUS | 321
THE FATE OF TERRESTRIALLY DERIVED DISSOLVED ORGANIC MATTER IN ONE SUB-TROPICAL AND THREE TEMPERATE LAKES OF VARYING TROPHIC STATUS
Freshwater ecosystems outgas a substantial quantity of carbon dioxide (CO2). The processing of dissolved organic matter (DOM) by biodegradation and photodegradation can result in the release of CO2, but the relative importance of these two processes is poorly understood. In contrast to previous findings, recent research in Arctic lakes and streams found that photodegradation was more important than biodegradation in the oxidation of terrestrially-derived DOC to CO2. We studied three temperate lakes ranging in trophic status (dystrophic, eutrophic, and oligotrophic) and one sub-tropical lake (dystrophic) to assess the relative importance of biodegradation vs. photodegradation in oxidizing DOC to CO2. We also assessed changes in dissolved oxygen, color, and spectral slope during the experiments. We found photodegradation was the dominant process in all lakes, but its importance varied with lake trophic status. When exposed to sunlight, DOC from the dystrophic lakes (temperate and sub-tropical) produced measurable quantities of CO2, whereas DOC from the eutrophic and oligotrophic lake exhibited a stronger response in their optical characteristics. Our results indicate sunlight is an important degradation process, but the amount of CO2 released varies with the trophic status of the lake.
- Biogeochemistry
- Carbon
- Organic Matter
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Presenters/Authors
Chris Dempsey
(), Gannon University, Biology Department, dempsey007@gannon.edu;
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Jennifer Brentrup
(), Dartmouth College, Department of Biological Sciences, Jennifer.A.Brentrup@dartmouth.edu;
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Sarah Magyan
(), Gannon University, Biology Department, magyan001@knights.gannon.edu;
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Lesley Knoll
(), University of Minnesota, Itasca Biological Station and Laboratories, lbknoll@umn.edu;
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Craig Williamson
(), Miami University, Global Change Limnology Laboratory, Department of Biology, willia85@miamioh.edu;
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