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.