Seasonal variations and hydrological management regulate nutrient transport in cascade damming: Insights from carbon and nitrogen isotopes.

Autor: Yang Y; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, PR China; College of Resources and Environmental Engineering, Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, PR China., Wang W; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, PR China; College of Resources and Environmental Engineering, Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, PR China. Electronic address: wfwang@gzu.edu.cn., Yu S; Ecohydrology Research Group, Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo N2L 3G1, Ontario, Canada., Yi Y; Department of Ocean Science and the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong 999077, PR China., Xu S; Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, PR China., Yao Y; School of Geographic Sciences, East China Normal University, Shanghai 201210, PR China., Zhong J; Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, PR China., Shi W; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, PR China; College of Resources and Environmental Engineering, Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, PR China., Chen S; Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, PR China., Wu Q; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, PR China; College of Resources and Environmental Engineering, Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, PR China., Ou Z; Power China GuiYang Engineering Corporation Limited, Guiyang 550081, PR China., Ding H; Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, PR China., Li SL; Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, PR China.
Jazyk: angličtina
Zdroj: Water research [Water Res] 2024 Nov 30; Vol. 271, pp. 122894. Date of Electronic Publication: 2024 Nov 30.
DOI: 10.1016/j.watres.2024.122894
Abstrakt: Reservoirs around the world have significantly altered the natural transport of nutrients in rivers. However, the specific effects of the cascade damming on the migration, transformation, and environmental consequences of these nutrients remain unclear. To address this knowledge gap, we analyzed spatiotemporal variations in water chemistry, nutrient concentrations, stable isotope of dissolved inorganic carbon (δ 13 C DIC ) and nitrate isotope (δ 15 N-NO 3 - ) in seven cascade reservoirs along the Wujiang River, each characterized by different regulatory regimes. Our findings reveal that the average absolute changes in concentrations of total nitrogen (TN), total phosphorus (TP), and silicon dioxide (SiO 2 ) during the wet season (WS, spring and summer) were 2.4, 1.4, and 1.1 times higher than those observed in the dry season (DS, autumn and winter). During the WS, the average apparent retention efficiency (*RET f ) values in the Hongjiadu reservoir were 97 % for TN, 98 % for TP, and 95 % for SiO 2 , indicating substantial nutrient consumption in the cascading reservoirs. Conversely, during the DS, the *RET f values for TN, TP, and SiO 2 were negative, suggesting notable nutrient accumulation within the reservoirs. The nutrient fluxes released downstream from the cascade reservoirs in the Wujiang River were significantly greater than the upstream inflow fluxes. These findings help demonstrate how downstream discharge across cascade reservoirs amplifies nutrient flux disparities due to dam construction. Our study enhances the understanding of how cascade dam construction impacts nutrient dynamics, supporting the optimization of reservoir operation models and advancing scientific water resource management and conservation efforts.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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