Apreliminary Study About The Partial Pressure And Influencing Factors Of The Dissolved Carbon Dioxide In The Mainstream And Tributaries Of The Central Three Gorges Reservoir

Since the industrial revolution, the concentration of GHGs (greenhouse gases),which is composed of CO2and CH4in the atmosphere, has been increasing due tohuman activity and fossil fuel burning. The increase of GHGs causes global warming,and brings an extremely adverse impact on the human survival environment andsustainable development of the national economy. Hydroelectric power has long beenwidely as a clean energy, but recent studies have found that artificial reservoirs canalso be the release of greenhouse gases in the atmosphere.From August2012to July2013, the partial pressure of CO2(p(CO2)), nutrients,water temperature, pH and dissolved oxygen (DO) have been determined monthly atthe mouth of the mainstream of the Three Gorges Reservoir and its three tributaries(Caotang River, Meixi River and Zhuyi River) to explore the contribution of themainstream and tributary to GHGS in the atmosphere. The results show that thedistribution and diffusion flux of CO2at the water-air interface in the mainstream andits three tributaries have an different regularity.○1The p(CO2) remained relativelyhigh in the mainstream water, while varied significantly seasonally in tributary water.Generally, the mainstream water is the “source” of the atmospheric CO2. CaotangRiver, Meixi River and Zhuyi River are the “sink” of the atmospheric CO2in summer.Caotang River is the “sink” in spring and autumn, but the “source” in winter. MeixiRiver and Zhuyi River are the “source” in spring, autumn and winter.○2The variationof p(CO2) is related with DO and pH significantly. The p(CO2) and pH have a goodcorrelation. The correlation coefficient for Caotang River, Meixi River and ZhuyiRiver are0.7123,0.8769and0.8464, respectively. The p(CO2) and pH for the Yangtzeriver have no obvious correlation. Similar to pH, the concentration of DO and p(CO2)also have a good correlation for the three tributaries. The correlation coefficient forCaotang River, Meixi River and Zhuyi River is0.6143,0.7670and0.7444,respectively.○3By estimate, the CO2flux of the Three Gorges Reservoir area is about1.199x106t/a, and it is about0.1792x106t/a for the main tributaries area. The CO2 emission flux from the Three Gorges Reservoir area is about6.7times that of themain tributaries area.