A decomposer is an organism that feeds on dead organisms and the waste products of other organisms. Decomposers help nutrients cycle back into the ecosystem. Some examples of decomposers are insects, earthworms and bacteria.
The four types of decomposers are microbes, such as bacteria and fungi; microfauna, such as protozoa; mesofauna, such as beetles; and macrofauna, such as earthworms. Decomposers make soil richer by adding organic compounds to it. Substances such as carbon, water and nitrogen are returned to the ecosystem through the actions of decomposers. These essential organisms consume organic matter, changing the substances back into their inorganic forms. Some inorganic substances that are made by decomposers and returned to the environment include phosphates, carbon dioxide and ammonium.