Long-term water diversion increased nutrient resources use efficiency and community stability of phytoplankton in subtropic lake

Water diversion is widely used in global water resource management, but its long-term effects on lake ecosystems, particularly phytoplankton community dynamics, remain insufficiently understood. In this study, a seven-year field monitoring program in San-shi-liu-jiao Lake (Fujian, China) revealed that water diversion significantly enhanced the resource use efficiency of nitrogen and phosphorus (RUEN and RUEP) in phytoplankton communities. This intervention introduced nutrient-rich water and increased phytoplankton biomass and diversity. Phytoplankton biomass increased from 1.27×106 cells/L to 2.63×106 cells/L, while the Shannon diversity and functional redundancy index significantly rose over time (P