The non-green organisms which live on the dead and decaying parts of producers and consumers, and derive food from them are called decomposers. They are also heterotrophic organisms. Some fungi and bacteria (microorganisms) are the major examples for decomposers in all ecosystems.
The basic structural and functional units of nature, where living organisms interact among themselves and also with their physical environment are called ecosystem. On the basis of their nutritional relationships, biotic components in an ecosystem are divided into three groups- the producers, the consumers and the decomposers.
The decomposers are also called micro consumers or saprotrophs.They does not ingest their food as consumers. Decomposers secrete different enzymes into the dead remains of plants and animals. These enzymes bring about the digestion of the dead remains of plants and animals and this process is called extracellular digestion. As a result of extracellular digestion, simpler inorganic substances are released. These substances are then utilized by the decomposers.
Decomposers in the ocean include hagfish, worms and other crap that floats in the sea, the bacteria, fungus, marine worms, sea slugs, sea worms and battle stars. Shrimp are decomposers too because like crabs, they take ocean waste, eat it and clean it up.