Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; Yangtze Eco-Environment Engineering Research Center, China Three Gorges Corporation, Beijing 100038, PR China.
J Environ Manage. 2024 Apr;357:120707. doi: 10.1016/j.jenvman.2024.120707. Epub 2024 Mar 29.
Water diversion has been widely utilized to enhance lake water quality and mitigate cyanobacterial blooms. However, previous studies have mainly focused on investigating the effects of water diversion on water quality or aquatic ecological health. Consequently, there is limited research investigating the combined impact of water diversion on the water quality and the ecological health of eutrophic lakes, and whether the WQI and phytoplankton assemblages demonstrate similar patterns following water diversion. In this study, the effects of water diversion on the ecosystem health of eutrophic lakes were comprehensively evaluated based on the WQI indices and phytoplankton assemblages during the NWDP-21 and WDP-22. The results showed that the annual mean of WQI increased from 52.02 to 54.36 after water diversion, which improved the water quality of the lake, especially NH-N and TN decreased by 58.6% and 15.2%, respectively. The phytoplankton assemblages changed significantly before and after water diversion, and we observed that the total biomass of phytoplankton decreased by 12.3% and phytoplankton diversity indices (Shannon-Wiener diversity, Pielou evenness, and Simpson index) increased by 8.6%-8.9% after water diversion, with an improvement in the connectivity and stability of the phytoplankton. Notably, enhanced adaptations of rare sub-communities for resource use in water diversion environments, and water diversion inhibited the dispersal ability of dominant functional groups, and the effects of hydrological disturbances on the structure of phytoplankton assemblage favored the ecological health of eutrophic lakes. VPA analysis further reveals that water diversion alters the drivers of phytoplankton functional group biomass and phytoplankton diversity. The results of the PLS-PM analysis clarify that water diversion indirectly impacts the total phytoplankton biomass and phytoplankton diversity primarily by modifying light availability. Significant correlations are observed between the dominant functional groups biomass and diversity indices of WQI. The trends in changes observed in water quality indices and phytoplankton following water diversion align with the evaluation of water ecological health. This study provides valuable guidance for the ecological management of the diversion project in Yilong Lake and serves as a reference for similar projects in other lakes.
引水已被广泛应用于提高湖水水质和减轻蓝藻水华。然而，先前的研究主要集中在调查引水对水质或水生生态健康的影响。因此，关于引水对富营养化湖泊水质和生态健康的综合影响，以及在引水后水质综合指数（WQI）和浮游植物群落是否表现出相似的模式，相关研究较少。本研究基于 WQI 指数和浮游植物群落，在 NWDP-21 和 WDP-22 期间，综合评估了引水对富营养化湖泊生态系统健康的影响。结果表明，引水后，WQI 的年平均值从 52.02 增加到 54.36，改善了湖水水质，尤其是 NH-N 和 TN 分别降低了 58.6%和 15.2%。浮游植物群落在引水前后发生了显著变化，我们观察到，引水后，浮游植物的总生物量减少了 12.3%，浮游植物多样性指数（香农-威纳多样性、皮埃罗均匀度和辛普森指数）增加了 8.6%-8.9%，浮游植物的连通性和稳定性得到了提高。值得注意的是，在引水环境中，稀有亚群对资源利用的适应能力增强，而引水抑制了优势功能群的扩散能力，水文干扰对浮游植物群落结构的影响有利于富营养化湖泊的生态健康。VPA 分析进一步揭示了引水改变了浮游植物功能群生物量和浮游植物多样性的驱动因素。PLS-PM 分析的结果表明，引水通过改变光照条件间接主要影响总浮游植物生物量和浮游植物多样性。WQI 的主导功能群生物量和多样性指数之间存在显著相关性。引水后水质指数和浮游植物的变化趋势与水生态健康评价一致。本研究为引隆湖引水工程的生态管理提供了有价值的指导，为其他湖泊类似项目提供了参考。
