关键词: 水化学性质, 碳循环, 水生植物, 光合作用, δ13CDIC, 李子湖

Abstract: In order to analyze the effect of aquatic plant on hydrochemistry and carbon cycle, the water temperature, pH, electric conductivity (EC), DO, TDS at eight monitoring sites in Lizi Lake in campus of Chongqing Jiaotong University were monitored. After analyzing the monitored data, it is shown that the hydrochemistry is affected by the photosynthesis of submerged plants. Atmospheric CO2 is the main carbon source of emergent plants distributed in the west shore. Emergent plants weaken the photosynthesis of algae, so that the influence of photosynthesis in the west shore is weaker than that of the east shore. In combination with analysis of the stable carbon isotope (δ13CDIC) of the water, DO and pH increase, and the dissolved inorganic carbon (DIC) concentration decreases along the east shore, which may be caused by sediment decomposition (nitrification) and the entry of atmospheric CO2 into the water body. The growth of emergent plants in the west shore not only aggravates carbonate dissolution, but also hinders the entry of atmospheric CO2 into the water body. The interaction of these factors leads to the gradual deviation of δ13CDIC in the water, but little change of concentration of DIC varies along the west shore. The hydrochemistry difference between two shores indicates that different types of aquatic plants have different effect on hydrochemistry.

Key words: hydrochemistry, carbon cycle, aquatic plants, photosynthesis, δ13CDIC, Lizi Lake