Why would you expect to find few plankton in the profundal zone of a lake?

The profundal zone of a lake is characterized by deep, dark waters that receive little to no sunlight, which inhibits photosynthesis. Since plankton, particularly phytoplankton, rely on sunlight for energy, their numbers are significantly reduced in this zone. Additionally, the lack of nutrients and limited mixing in the profundal zone further contributes to the scarcity of plankton. As a result, this area supports fewer organisms compared to the well-lit and nutrient-rich zones above.