Seasonal and diurnal methane and carbon dioxide emissions from the littoral area of the Miyun Reservoir in Beijing, China

Reservoirs have been regarded as hot spots for greenhouse gas emissions since the 1990s. However, there is scant research about littoral zones of reservoirs. In the present study, static closed chamber and gas chromatograph techniques were used to measure methane (CH4) and carbon dioxide (CO2) flux in the littoral area of a temperate reservoir from 2009 to 2010. The littoral area comprises three zones, namely supralittoral, eulittoral and infralittoral. The patterns of CH4 and CO2 emissions from these three littoral zones were significantly different during the sampling periods, with the eulittoral zone having the highest CH4 flux and the supralittoral zone having the highest CO2 flux. Temperature and biomass correlated with CH4 and CO2 emissions. Measurement of CO2 emissions after removing vegetation varied in each zone and according to time of sampling. A large littoral area of the reservoir sampled herein will be submerged and converted to a pelagic area with deep standing water after the South to North Water Transfer Project is completed, in 2050. The results of the present study suggest further research and monitoring are needed, and should focus on likely effects of extreme climate events and the effects of human-mediated factors on greenhouse gas emissions.