The researchers studied phytoplankton in lakes to see how species changed over time and space. They found that the types of phytoplankton varied between spring and summer, with pH levels affecting the changes. In summer, the diversity of phytoplankton was higher and influenced by nutrients and light availability. The environment and spatial factors together explained more of the differences in phytoplankton composition in summer compared to spring. Lakes with similar changes in phytoplankton over two seasons had more similar communities in summer. Overall, the study shows that environmental factors play a big role in shaping phytoplankton communities over time and space.