Both runoff and water diversion can interfere with the physical and chemical environment of a lake and affect aquatic organisms. In this study, previously obtained data were used to analyze the phytoplankton community, water quality, water level, and temperature in Dongping Lake (DPH) before, during, and after the water diversion caused by the South-to-North Water Transfer Project. The results showed that the total density and diversity index of phytoplankton decreased in the water transfer period, and was related to low temperature. Temperature also affected the recovery of phytoplankton community structure when the water transfer period ended. In a water transfer cycle, changes in dominant genera were more drastic than that of a whole phytoplankton community, and dominant genera were sensitive to total phosphorus (TP) and total nitrogen (TN) changes. Water transfer alleviated the deterioration of water quality in DPH, but water transfer process increased the risk of water pollution. Runoff from Dawen River carried TN, TP, and chemical oxygen demand (COD) into DPH in the rainy season, which indirectly affected phytoplankton, while it also carried phytoplankton directly into DPH. Overall, these findings provide a clear understanding of the impact of water transfer projects on ecology in shallow lakes.

中文翻译：

---

径流与逆调水交替影响下浅湖浮游植物的演替

径流和引水都会干扰湖泊的物理和化学环境并影响水生生物。本研究利用此前获得的数据分析了南水北调引水前、中、后东平湖（DPH）的浮游植物群落、水质、水位和温度。结果表明，输水期浮游植物总密度和多样性指数下降，与低温有关。调水期结束时，温度也影响浮游植物群落结构的恢复。在一个输水循环中，优势属的变化比整个浮游植物群落的变化更为剧烈，和优势属对总磷（TP）和总氮（TN）变化敏感。调水缓解了DPH水质的恶化，但调水过程增加了水污染的风险。雨季大汶河径流将TN、TP和化学需氧量（COD）带入DPH，间接影响浮游植物，同时也将浮游植物直接带入DPH。总体而言，这些发现为调水工程对浅湖生态的影响提供了清晰的认识。同时它还将浮游植物直接带入 DPH。总体而言，这些发现为调水工程对浅湖生态的影响提供了清晰的认识。同时它还将浮游植物直接带入 DPH。总体而言，这些发现为调水工程对浅湖生态的影响提供了清晰的认识。