Decomposers also belong to heterotrophs, also known as small consumers. Such as microorganisms (bacteria, fungi, etc. ) in the biosphere, they can decompose complex animal and plant carcasses and release simple compounds that producers can reuse, which is just the opposite of producers. Decomposers are also indispensable in the cycle mechanism of ecosystems. Without decomposers, the earth will be submerged by the remains of animals and plants, and nutrients will be bound in them and cannot be recycled. Therefore, decomposers also play a very important role in the material cycle of ecosystems.

Organisms mainly refer to bacteria, fungi and some protozoa. They obtain energy and nutrients by decomposing animal and plant excreta and dead organic residues, and at the same time degrade complex organic compounds into simple inorganic compounds or elements, which return to the environment and are reused by production organisms, so they are also called reduced organisms. Decomposition organisms are widely distributed in ecosystems, constantly promoting the circulation of natural substances.

Decomposers are not necessarily microorganisms, such as earthworms.