State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, China.
College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, 225127, China.
Environ Geochem Health. 2023 Jun;45(6):3025-3039. doi: 10.1007/s10653-022-01383-w. Epub 2022 Sep 22.
Due to the allochthonous input of nutrients and species, the cumulative effects of water diversion on water-receiving lakes deserve attention. Taking the water diversion project from the Yangtze River to Lake Taihu (WDYT) as an example, we explored the temporal effects of WDYT on the phytoplankton community and physicochemical habitat of Lake Taihu in autumn and winter from 2013 to 2018. Although the short-term diversion significantly increased the risk of importing nutrients, the relatively high quality of the diversion water compared with other inflow rivers had improved the water quality of the water-receiving lake region. The seasonal water diversion significantly increased phytoplankton diversity and community network complexity and reshaped the lacustrine community to be diatom-dominated with their relative proportions of 24.1-64.9% during water diversion periods. The contributions of physicochemical habitat changes induced by water diversion to variations in phytoplankton communities were 24.0-28.0%. The differences in phytoplankton diversity, community composition and physicochemical habitat in the water-receiving lake region between the diversion and non-diversion years were more evident than those between the non-diversion years in the same season, when comparing the multivariate dispersion indices among them. However, the lacustrine phytoplankton community during non-diversion periods still has not been essentially altered after several years of diversion, so the pulse effects of short-term water diversion were more obvious than the long-term cumulative impacts. Better control of allochthonous nutrients, appropriate increase in inflow water, adhering to the long-term operation, should be effective to enhance ecological benefits of such water diversion projects.
由于营养物质和物种的外来输入，调水工程对受水湖泊的累积效应值得关注。以长江引水至太湖工程（WDYT）为例，我们探讨了 WDYT 在 2013 年至 2018 年秋冬季节对太湖浮游植物群落和理化生境的时间效应。尽管短期引水显著增加了输入营养物质的风险，但与其他入流河流相比，引水水质相对较好，改善了受水湖区的水质。季节性调水显著增加了浮游植物多样性和群落网络复杂性，并重塑了湖泊群落，使其以硅藻为主，相对比例为 24.1-64.9%，在引水期间。引水引起的理化生境变化对浮游植物群落变化的贡献为 24.0-28.0%。与非引水年同期相比，引水和非引水年受水湖区浮游植物多样性、群落组成和理化生境的差异更为明显，其中多变量离散指数之间存在差异。然而，经过几年的引水，非引水期间的湖泊浮游植物群落仍未发生本质变化，因此短期引水的脉冲效应比长期累积影响更为明显。更好地控制外源营养物质，适当增加入流水量，坚持长期运行，应能有效提高此类调水工程的生态效益。
