The researchers studied the phytoplankton community in Hedi Reservoir in South China. They found that the types of phytoplankton varied between seasons and locations in the reservoir. Phytoplankton biomass was higher in the flood season due to warmer temperatures and nutrient input. The dominant species of phytoplankton also changed between dry and flood seasons, with phosphorus playing a key role in this variation. Overall, the study showed that the structure of the phytoplankton community in Hedi Reservoir is influenced by seasonal changes and nutrient levels.