Researchers studied how different types of bacteria live in a lake formed by mining activities. They looked at how these bacteria change with depth in the lake. The water in the lake is more acidic near the surface. They found that the type of bacteria present changes with depth, with more diverse bacteria found deeper in the lake. Bacteria near the surface are chosen based on their abilities, while deeper bacteria are more randomly selected. Bacteria near the surface also work together more often. The acidity of the water is the main factor influencing the types of bacteria present in different parts of the lake. Overall, the study shows that the environment in the lake plays a big role in determining which bacteria live there.