Water layers refer to the different levels of water in a body of water, such as a lake or ocean, that have distinct characteristics. These layers can vary in temperature, salinity, and density. For example, in oceans, the surface layer is warmer and less dense, while deeper layers are colder and denser. This stratification affects marine life and water circulation. In lakes, water layers can change with the seasons. During summer, the top layer, or epilimnion, warms up, while the bottom layer, or hypolimnion, remains cold. In fall, mixing can occur, redistributing nutrients and oxygen throughout the water column, which is essential for aquatic ecosystems.