Epilimnion
The epilimnion is the layer that is most affected by sunlight, its thermal energy heating the surface, thereby making it warmer and less dense.
On the topside of the epilimnion it is in contact with air, which leaves it open to wind action, which allows the water to experience turbulence.
This is due to the fact that since the epilimnion is in contact with air and is above everything, it interacts with the sun and heat more, making it warmer than the layers below.
[5] In most stratified lakes, seasonal changes in the spring and fall air temperature cause the epilimnion to warm up or cool down.
[8] The epilimnion is also an area of concern for algal blooms due to phosphorus and nitrogen runoff from terrestrial sources.
Because of its closeness to the surface, and being the area that receives the most sunlight, the epilimnion is a great home for phytoplankton, and other primary producers.
In response to large amounts of algae and phytoplankton being present, many fish species are common in this layer as they look for their source of food.
I. The Epilimnion
II. The Metalimnion
III. The Hypolimnion
The scales are used to associate each section of the stratification to their corresponding depths and temperatures. The arrow is used to show the movement of wind over the surface of the water which initiates the turnover in the epilimnion and the hypolimnion.