LI Siqi1, CUI Gaoyang2,3, LI Qinkai1, HUANG Jun2,3, TAO Yuele1, YANG Mengdi1, ZHANG Jun1, LI Xiaodong1
(1. Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072,China;
2. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081,China;
3. University of Chinese Academic of Sciences, Beijing 100049,China)
Abstract: With the rapidly rising of hydropower development, the ecological environment effect resulted from river damming needs attention. To explore the impacts of dam interception on the biogeochemical cycling of nutrients in the Jialing River, the water samples (inflow, outflow, and stratified water) in four representative cascade reservoirs, located in the middle and lower reaches of Jialing River, were collected in January (winter, dry season) and July (summer, wet season), 2016, respectively, while the hydrochemical compositions and concentrations of nutrients (total dissolved nitrogen as TDN, NO2？, NO3？, NH4+, and dissolved silicon as DSi) were analyzed. The results showed that the concentrations of Na+ and K+ were increasing from upstream to downstream due to the influences of human activities. Meanwhile, the concentrations of TDN and DSi were higher in dry season (winter) than those in wet season (summer) because of the dilution by precipitation. For the stratified waters, the contents of nitrogen and silicon were higher in surface water and lower in deep layer, particularly in summer, and the negative correlations between NO3？ and NH4+, NO2？ were found, which both suggesting the nitrogen transformations in the studied cascade reservoirs would mainly manifest as assimilation of the algae in surface water, nitrification in shallow water, and denitrification in deep water.
Key Words: Jialing River; hydrochemical characteristics; Cascade Reservoirs; spatial-temporal distribution of nitrogen and silicon；transformation of inorganic nitrogen
EARTH AND ENVIRONMENT Vol.46, No.4, Tot No.324, 2018, Page 321-330