adaptations is the lack of rigid structures in freshwater plants. This is due to the density of the water (much higher than that of an open air environment), which 'pushes' against the plant in its daily life. This allows such plants to be more flexible against oncoming water tides, and prevents damage to the plant.
As plants require a minimum concentration of gases in their diet such as carbon dioxide, they require a degree of buoyancy so that contact can be made with the open air environment. Adaptations may include;
Air Spaces - Air spaces in the plant will decrease density and increase buoyancy.
Broad Leaves - Broader leaves will spread their weight more evenly across the water surface allowing them to float.
Waxy Cuticle - On the upper half to allow water to run off the surface to prevent the weight of the water dragging the leaves under the surface.
ANIMALS: Many animals live in freshwater ecosystems. Some need the movement of the stream or river water to survive. In fast moving waters animals that have to hold onto rocks and the bottom may have suction-cup like structures on their bodies. Others thrive in still water environments, like lakes. There are a variety of fish, birds, insects, amphibians, and crustaceans that make freshwater biomes their home. One important freshwater animal in the United States is the trout. Many people love to fish for, and eat trout. Trout live in both streams and rivers. They eat fish and insects. Estuaries are rich in animal life and are often a protected area where juvenile creatures seek refuge. There are also a variety of animals who live in estuaries that people like to eat, for example clams, shrimp and lots of fish.