What does "lake turnover" primarily impact?

Lake turnover is a natural process that occurs in many lakes, particularly those in temperate regions. This process greatly affects water temperature and oxygen levels within the lake. During turnover, colder, denser water at the bottom of the lake rises to the surface, while warmer, less dense water descends. This mixing results in a uniform temperature throughout the layers of the water column, which can significantly influence the amount of oxygen dissolved in the water.

As the water mixes, oxygen that was previously present in the deeper layers is distributed evenly, which is essential for aquatic life. The autumn and spring turnover periods can be especially critical, as they can determine the health of the aquatic environment by affecting not just the temperature, but also the nutrient dynamics and the overall ecology of the lake.

The other potential impacts listed, such as fish populations, surface area exposure, and water clarity, may be influenced by lake turnover, but they are secondary effects rather than the primary impact. The immediate and most significant changes are those related to temperature and oxygen levels, which are vital for the survival of aquatic organisms.