The researchers studied bacterial communities in 25 lakes in Brazil to see how they change with distance. They found that different types of bacteria were more common in lakes with different environments. As the lakes got further apart, some lakes had more similar bacteria populations, while others had more unique ones. This was likely because bacteria can't travel as easily over long distances, and some lakes have more bacteria due to wind. This shows that the type of bacteria in a lake can be influenced by both the environment and how far away other lakes are.