A standing water ecosystem is also known as a lentic ecosystem, and it is defined as a body of fresh water, such as a pond or lake. A lentic ecosystem is characterized by still water and contains organisms such as algae, rooted and floating-leaved plants, invertebrates, amphibians, reptiles and fish.
Smaller bodies of freshwater have two main zones, the pelagic zone and the benthic zone. The pelagic zone includes water that touches neither the shore nor the bottom, while the benthic zone includes water touching the shore and the bottom.
The profundal zone is present in larger lakes, and it includes water at depths where no light penetrates. The primary producers of energy in a standing water ecosystem are algae and plants.