Greenhouse gas emissions (CO2-CH4-N2O) along a large reservoir-downstream river continuum: the role of seasonal hypoxia

作者：Dan Yu, Zetao Wu, Weidong Guo, Nengwang Chen · 年份：2025 · DOI：10.5194/egusphere-egu25-19839 · 被引用次数：1 · 研究领域：Marine and coastal ecosystems、Fish Ecology and Management Studies、Atmospheric and Environmental Gas Dynamics

Recent studies suggest that hypolimnetic respiration contributes significantly to greenhouse gas (GHG) emissions from deep reservoirs. This study investigates the roles of aerobic and anaerobic processes, as well as priming (enhanced organic matter processing), in regulating GHG production and emissions across the reservoir-downstream continuum. High-resolution, annual time-series data from Shuikou Reservoir in southeastern China, which experiences seasonal hypoxia, shows that aerobic CO2 production predominates in spring and summer, with higher rates at higher temperatures. Anaerobic CO2 production later in the season stimulates CH4 and N2O production. Priming in spring enhances both aerobic and anaerobic GHG production. A spring flood event led to the highest daily CO2 efflux through the flushing of GHG-enriched waters. Turbine degassing accounted for 59%, 93%, and 63% of annual CO2, CH4, and N2O emissions, respectively. The reservoir-downstream continuum emitted 218.5±18.9 Gg CO2-equivalent per year, emphasizing the importance of managing GHGs and recalcitrant dissolved organic carbon (RDOC) for carbon neutrality in hydroelectric reservoirs.