decomposer An organism that obtains energy from the chemical breakdown of dead organisms or animal or plant wastes. Decomposers, most of which are bacteria and fungi, secrete enzymes onto dead matter and then absorb the breakdown products (see saprotroph). Many decomposers (e.g. nitrifying bacteria) are specialized to break down organic materials that are difficult for other organisms to digest. Decomposers fulfil a vital role in the ecosystem, returning the constituents of organic matter to the environment in inorganic form so that they can again be assimilated by plants. Compare detritivore. See also carbon cycle; nitrogen cycle.

decomposer A term that is generally synonymous with ‘microconsumer’. In an ecosystem, decomposer organisms (mainly bacteria and fungi) enable nutrient recycling by breaking down the complex organic molecules of dead protoplasm and cell walls into simpler organic and (more importantly) inorganic molecules which may be used again by primary producers. Recent work suggests that some macroconsumers may also play a role in decomposition (for example, detritivores, in breaking down litter, speed its bacterial breakdown). In this sense ‘decomposer’ has a wider meaning than that traditionally implied. See also CONSUMER ORGANISM.

decomposer A term that is generally synonymous with ‘microconsumer’. In an ecosystem, decomposer organisms (mainly bacteria and fungi) enable nutrient recycling by breaking down the complex organic molecules of dead protoplasm and cell walls into simpler organic and (more importantly) inorganic molecules which may be used again by primary producers. Recent work suggests that some macroconsumers may also play a role in decomposition (for example, detritivores, in breaking down litter, speed its bacterial breakdown). In this sense ‘decomposer’ has a wider meaning than that traditionally implied. See also consumer organism.

decomposer A heterotroph which feeds on detritus, breaking it down into its constituent nutrients, some of which it utilizes and some of which it releases to be recycled in the ecosystem.