An aquatic ecosystem is composed of living organisms that exist in a body of water and their interactions with their environment. It includes biotic factors such as producers, consumers, decomposers, herbivores, carnivores and omnivores. There are over 1 million aquatic animal species including 32,000 fish species as well as reptiles, amphibians and mammals. Aquatic plants have adapted to live in water and include algae, floating, submerged and emerged varieties. Common examples of each type are also provided.