The researchers studied the different sizes of algae in Lake Dongting to see how they change over time and what factors drive these changes. They found that small algae (3-20 μm) are the main contributors to algae biomass in the lake, especially in winter. As spring approaches, even smaller algae (0-3 μm) start to increase in number, peaking in summer. Larger algae (>20 μm) make up the smallest proportion of the total algae biomass. Factors like temperature, water levels, nutrients, and pH play a big role in determining the size structure of algae in Lake Dongting.