Fungi and bacteria are primary decomposers. Different types of worms, mushrooms, termites, snails and slugs are also considered to be decomposers. Decomposers break down the organic matter in the dead bodies of plants and animals.
Decomposers are called nature's recyclers, as they break down the organic matter in an ecosystem. The term "organic matter" refers to the matter that comes from living organisms. Decomposers convert all organic matter into carbon dioxide, which they respire, and nutrients like nitrogen, phosphorus and magnesium, that can be used by the producers. This process resupplies nutrients to the ecosystem and results in greater primary production. Decomposers play one of the most important roles to balance the food chain of an ecosystem.
Bacteria and fungi do the majority of decomposition activity. Fungi work on plants, breaking down cellulose and lignin, the largest of the complex carbohydrates. Bacteria work on everything from animal proteins to plant carbohydrates. Once these complex compounds are broken down into smaller molecules, they can be ingested by small animals such as insects or taken up by plants and thus recycle the food chain again. Decomposers are also important as they remove the dead and decaying organic matter from ecosystems and make the environment clean and inhabitable.