Freshwater Ecosystem

Tiny invertebrates live among floating ferns (Salvinia is one example) in freshwater environments. Freshwater aquatic biological systems are supported in part by symbitoic cyanobacteria that live near the rhizines of the ferns. The ferns and the cyanobacteria do photosynthesis and the cyanobacteria introduce biologically useful nitrogen into the freshwater ecosystem. In rice paddies, where these organisms are abundant, small fish consume the invertebrates and in turn are eaten by subsistence farmers. These aquatic systems support billions of people around the world!