The researchers studied phytoplankton in four reservoirs in China's Weihe River Basin. They identified 40 species and 8 genera of phytoplankton, with varying cell density and biomass. Different reservoirs had different phytoplankton compositions, mainly diatom-chlorella. The community structure was influenced by trophic levels, illumination, and temperature. Shitouhe and Xiluoyu reservoirs had similar phytoplankton communities, while Taoqupo and Xijiao reservoirs formed separate groups. Phytoplankton cell density and biomass decreased in the order of Xijiao, Taoqupo, Xiluoyu, and Shitouhe reservoirs.