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PhD Project Experimentally simulated global warming and nitrogen enrichment effects on methane emissions in a marsh We determined methane emissions from a littoral wetland in a field mesocosm experiment under influence of simulated warming and enhanced nitrogen deposition. Methane emissions were estimated using funnel traps for ebullition fluxes, and Fick's law for diffusive fluxes. Surprisingly, methane emissions were not found to be significantly affected by either increased water temperature or by nitrate addition. Littoral zone methane emissions were determined to be substantial and primarily resulting from ebullition (average 17 - 203 mg methane m-2 d-1).We estimated that the littoral zone is responsible for over 99% of the total methane emissions from the lake and suggest that ebullition may even have a stimulating effect on methane production due to indirectly reducing dissolved oxygen flux into the sediment. These results emphasize the importance of littoral wetlands as sources of greenhouse gas emissions (Flury et al. 2010). |
Reed stand in Lake Hallwil. |
Funnel traps used in the methane experiment. |