Simulating Methane Emissions from the Littoral Zone of a Reservoir by Wetland DNDC Model

Abstract: The littoral zone of freshwater ecosystems is believed to be a hotspot for methane (CH4) emissions, but in situ measurements are rare. This paper reports a study of CH4 fluxes from the Miyun Reservoir near Beijing in China based on an integrated observational and modelling approach. CH4 fluxes were measured at three sites with different water levels containing nine representative vegetation communities. A process-based model, Wetland-DNDC, was tested against observations for its applicability in simulating CH4 fluxes from the littoral zone of the reservoir. The R2 values, which showed correlation between the modeled and observed results, were 0.89, 0.81 and 0.49 for the deep water, shallow water and seasonally flooded sites, respectively. The modeled data indicated that the observed CH4 fluxes were mainly driven by water level fluctuations, soil temperature and soil organic matter content. The modeled average annual flux from the littoral zone of Miyun Reservoir was 15.1 g CH4.m-2, which was com...