There are two main sources of oxygen to the photic zone: atmospheric mixing and photosynthesis. Oxygen is dissolved when air interacts with water on the surface, and is increased with wave and wind action. Unlike the profundal zone, the limnetic zone is the layer that receives sufficient sunlight, allowing for photosynthesis. For this reason, it is often simply referred to as the photic zone. The limnetic zone is the most photosynthetically-active zone of a lake since it is the primary habitat for planktonic species. Because phytoplankton populations are densest here, it is the zone most heavily responsible for oxygen production within the aquatic ecosystem.
