EAPSI: Day vs night greenhouse gas emissions from the draw-down zone of China's Three Gorges Reservoir

水电站水库排放二氧化碳（CO2）和甲烷（CH4）等吸热气体，就像它们被设计用来取代的燃煤发电厂一样。当河水沃茨携带的碳进入缓慢流动的水库沃茨时，就会沉淀在沉积物中。当沉积物暴露于含氧水时，微生物将碳转化为CO2。没有氧气，微生物也会产生CH4。 因此，产生的气体的比例取决于水中氧气的存在，这在白天和黑夜之间变化。 以前对水库的CO2和CH4排放量的研究几乎完全是在白天进行的。这项研究将与中国科学院的陈怀博士合作，测量世界上最大的水库之一中国三峡的二氧化碳和甲烷排放量。这些测量在白天和夜晚进行，将有助于更准确地了解水电在整个发展中世界扩展时产生的CO2和CH4排放量。随着三峡水库水位的每年升降，其边缘20%的库区被淹没和脱水。这一下降带中的衰老植物是微生物氧化的丰富和常规基质。本研究将测量溶解和气泡形式的下拉区的DIEL CO2和CH4通量。虽然在其他水库的研究在白天进行了类似的测量，但1）光合作用（消耗CO2并产生氧气），2）呼吸作用（消耗氧气）和3）大气压（可能控制气泡释放）的昼夜差异可能意味着目前对水库中CO2和CH4通量的估计是不准确的。NSF EAPSI奖是与中国科技部合作资助的。

Hydropower reservoirs emit heat-trapping gases such as carbon dioxide (CO2) and methane (CH4) like the coal-fired power plants they were designed to replace. Carbon carried by river waters settles in sediments when it enters slow-moving reservoir waters. When sediments are exposed to oxygenated water, microbes convert carbon to CO2. Without oxygen, microbes also produce CH4. Therefore, the proportions of gases produced depend on the presence of oxygen in water, which varies between day and night. Previous studies of CO2 and CH4 emissions from reservoirs have been almost exclusively conducted during the day. In collaboration with Dr. Huai Chen of the Chinese Academy of Sciences, this study will measure CO2 and CH4 emissions from one of the world's largest reservoirs, China's Three Gorges. These measurements, conducted during day and night, will contribute to a more accurate understanding of CO2 and CH4 emissions from hydropower as it expands throughout the developing world.Production of CO2 and CH4 in reservoirs varies spatially, as well as temporally. As water levels in the Three Gorges Reservoir rise and fall annually, 20% of the reservoir area around its margins is flooded and dewatered. Senesced plants in this draw-down zone are a rich and regular substrate for microbial oxidation. This study will measure diel CO2 and CH4 fluxes from the draw-down zone in dissolved and bubble form. Though studies in other reservoirs have taken similar measurements during the day, diel differences in 1) photosynthesis, which consumes CO2 and produces oxygen, 2) respiration, which consumes oxygen, and 3) atmospheric pressure, which may govern bubble release, could mean that current estimates of CO2 and CH4 fluxes in reservoirs are inaccurate. This NSF EAPSI award is funded in collaboration with the Chinese Ministry of Science and Technology.