Main Participants: WANG Yuchun, XIAO Shangbin, HU Mingming, LI Shanze, NIU Fengxia, LEI Dan, WAN Xiaohong, BAO Yufei, WEN Jie, CHEN Min
Reservoir interception has altered the natural runoff and material cycle process of rivers. The reservoir carbon flux and its biogeochemical cycle process are complex, which are the frontiers of the current inland hydrology and ecological environment research. The reservoir carbon flux is also a major issue related to the green energy attribute of hydropower and sustainable development. The weak theoretical research and the lack of awareness of relevant mechanisms seriously restrict the scientific evaluation of greenhouse gas emission reduction benefits of large hydropower projects. The reservoir carbon flux of the Three Gorges Project is directly related to the national strategy of China’s energy security and sustainable development of hydropower, and it is an important work for the protection of the Yangtze River and the development of the Yangtze River Economic Belt.
The project has carried out long-term observation of fixed station and key process research, and made important theoretical innovation in carbon flux and biogeochemical cycle mechanism of deep reservoirs.
(1) Observation in fixed location of carbon flux and its environmental impact factors in important water areas in the Three Gorges Reservoir. Having developed the technology and equipment for the dynamic and continuous observation of air-water interface carbon flux with independent intellectual property, which has broken through the technical bottleneck of the current academic circles; carried out for the first time the continuous and high-resolution underway online observation of greenhouse gas in the main stream and tributaries of the Three Gorges Reservoir, systematically improving the observation efficiency and accuracy of greenhouse gas dissolved in different depths of the Reservoir, obtaining the long-term observation data and filling the carbon flux data gap of reservoirs in subtropical regions; and mastered the hydrochemical change characteristics and the thermodynamic equilibrium relationship of carbon transformation in the water environment, reaching a further understanding of the thermodynamic equilibrium relationship of water environment of the Three Gorges Reservoir in its process of swampiness.
(2) Theoretical study on key processes of carbon biogeochemical cycle in the Three Gorges Reservoir. With the combined use of multidisciplinary modern technologies, including isotope tracing, molecular biology and environmental microbiology, this project has studied the mechanism of key interfaces and important processes of the Three Gorges Reservoir, understood the occurrence state and driving process of greenhouse gas in water body from the three-dimensional point-line-surface-body perspective of deep reservoir, and clarified the dynamics of carbon source flux and biogeochemical mechanism of key interfaces and processes in the Three Gorges Reservoir.
(3) Carbon emissions accounting check and comprehensive impact assessment of the Three Gorges Reservoir. Having revised and corrected the preliminary estimation results of water-air carbon exchange flux of the Three Gorges Reservoir based on the quantitative analysis of key processes, put forward a new method to quantitatively calculate the carbon emission flux of the Reservoir in different operation modes, reaching an objective understanding of the emission level generated by the Reservoir, providing data and theoretical basis for the scientific evaluation of the green energy benefit of the Project.
Fig. 1 Hydrochemical Analysis and pCO2 Distribution Characteristics at Different Depths
Fig. 2 Distribution of Dissolved Methane Concentration in the Three Gorges Reservoir
Fig. 3 Distribution of Dissolved Methane and Carbon Dioxide Concentration in the Mainstream of the Three Gorges Reservoir
