环境地球化学国家重点实验室知识库

Two reservoirs in series in a Karst area were investigated in this study to understand the impact of river damming on riverine C cycling. Monthly sampling strategy was performed in Hongfeng and Baihua reservoirs, from July, 2007 to June, 2008. DIC and its isotopic compositions were determined. pCO₂, and calcite saturation index (SIc) were then calculated. Results show that δ¹³C-DIC in surface water of these reservoirs responded clearly to the transformation between photosynthesis and respiration, which also changes the inorganic C equilibrium. Based on monthly monitoring data, the major biogeochemical processes along the water column in these reservoirs, was also discussed. It is noted that hypoliminion introduction for hydropower generation and then release can lead to the discontinuity of water chemistry along a river course, and has adverse effects on the downstream environment.