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The fungi on this tree are decomposers

Decomposers (or saprotrophs) are organisms that break down dead or decaying organisms, and in doing so carry out the natural process of decomposition.^[1] Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. Decomposers can break down cells of other organisms using biochemical reactions that convert the prey tissue into metabolically useful chemical products, without need for internal digestion.^[2] Decomposers use dead organisms and non-living organic compounds as their food source. The examples are:

Bacteria [edit]

Bacteria are important decomposers; they are widely distributed and can break down just about any type of organic matter.^[3] A gram of soil typically contains 40 million bacterial cells, and the bacteria on Earth form a biomass that exceeds that of all living plants and animals. Bacteria are vital in the recycling of nutrients, and many steps in nutrient cycles depend on these organisms.

Fungi [edit]

The primary decomposers of litter in many ecosystems are fungi. Unlike bacteria, which are unicellular organisms, most saprotrophic fungi grow as a branching network of hyphae. While bacteria are restricted to growing and feeding on the exposed surfaces of organic matter, fungi can use their hyphae to penetrate larger pieces of organic matter. Additionally, only wood-decay fungi have evolved the enzymes necessary to decompose lignin, a chemically complex substance found in wood. These two factors make fungi the primary decomposers in forests, where litter has high concentrations of lignin and often occurs in large pieces. Fungi decompose organic matter by releasing enzymes to break down the decaying material, after which they absorb the nutrients in the decaying material.^[4] Hyphae used to break down matter and absorb nutrients are also used in reproduction. When two fungi's hyphae grow close to each other, they will then fuse together and form another fungus.^[4]

Worms [edit]

Various types of worms are also considered decomposers^{[citation needed]}, as they act as scavengers. For example, a worm that begins to consume an apple helps to hasten its decay by removing parts of the skin and flesh, exposing the interior of the fruit to the elements and to other decomposers.

See also [edit]

• Chemotroph
• Detritivore
• Micro-animals
• Microorganism

References [edit]

v t e Feeding behaviours Carnivores adult Hematophagy Insectivore Lepidophagy Man-eater Molluscivore Mucophagy Myrmecophagy Ophiophagy Piscivore Avivore Spongivore Vermivore Herpetivore reproductive Oophagy Paedophagy Placentophagy Breastfeeding Weaning cannibalistic Cannibalism Human cannibalism Self-cannibalism Sexual cannibalism Herbivores Folivore Frugivore Graminivore Granivore Nectarivore Palynivore Xylophagy Osteophagy Cellular Phagocytosis Myzocytosis Others Bacterivore Fungivore Coprophagia Detritivore Geophagy Omnivore Planktivore Xenophagy Methods Apex predator Bait balls Bottom feeding Browsing Feeding frenzy Filter feeding Grazing Hypercarnivore Intraguild predation Kleptoparasitism Scavenging Trophallaxis Predation Antipredator adaptation Carnivorous plant Carnivorous fungus Carnivorous protist Category:Eating behaviors

v t e Modelling ecosystems – trophic components General Abiotic component Abiotic stress Behaviour Biogeochemical cycle Biomass Biotic component Biotic stress Carrying capacity Competition Ecosystem Ecosystem ecology Ecosystem model Keystone species List of feeding behaviours Metabolic theory of ecology Productivity Producers Autotrophs Chemosynthesis Chemotrophs Foundation species Mixotrophs Myco-heterotrophy Mycotroph Organotrophs Photoheterotrophs Photosynthesis Photosynthetic efficiency Phototrophs Primary nutritional groups Primary production Consumers Apex predator Bacterivore Carnivores Chemoorganotroph Foraging Generalist and specialist species Intraguild predation Herbivores Heterotroph Heterotrophic nutrition Insectivore Mesopredator release hypothesis Omnivores Optimal foraging theory Predation Prey switching Decomposers Chemoorganoheterotrophy Decomposition Detritivores Detritus Microorganisms Archaea Bacteriophage Environmental microbiology Lithoautotroph Lithotrophy Microbial cooperation Microbial ecology Microbial food web Microbial intelligence Microbial loop Microbial mat Microbial metabolism Phage ecology Food webs Biomagnification Ecological efficiency Ecological pyramid Energy flow Food chain Trophic level Example webs Cold seeps Hydrothermal vents Intertidal Kelp forests Lakes North Pacific Subtropical Gyre Rivers San Francisco Estuary Soil Tide pool Processes Ascendency Bioaccumulation Cascade effect Climax community Competitive exclusion principle Consumer-resource systems Copiotrophs Dominance Ecological network Ecological succession Energy quality Energy Systems Language f-ratio Feed conversion ratio Feeding frenzy Mesotrophic soil Nutrient cycle Oligotroph Paradox of the plankton Trophic cascade Trophic mutualism Trophic state index Defense/counter Animal coloration Antipredator adaptations Camouflage Deimatic behaviour Herbivore adaptations to plant defense Mimicry Plant defense against herbivory Predator avoidance in schooling fish

v t e Modelling ecosystems – other components Population ecology Abundance Allee effect Depensation Ecological yield Effective population size Intraspecific competition Logistic function Malthusian growth model Maximum sustainable yield Overpopulation in wild animals Overexploitation Population cycle Population dynamics Population modeling Population size Predator–prey equations Recruitment Resilience Small population size Stability Species Biodiversity Density-dependent inhibition Ecological effects of biodiversity Ecological extinction Endemic species Flagship species Gradient analysis Indicator species Introduced species Invasive species Latitudinal gradients in species diversity Minimum viable population Neutral theory Occupancy-abundance relationship Population viability analysis Priority effect Rapoport's rule Relative abundance distribution Relative species abundance Species diversity Species homogeneity Species richness Species distribution Species-area curve Umbrella species Species interaction Antibiosis Biological interaction Commensalism Community ecology Ecological facilitation Interspecific competition Mutualism Storage effect Spatial ecology Biogeography Cross-boundary subsidy Ecocline Ecotone Ecotype Disturbance Edge effects Foster's rule Habitat fragmentation Ideal free distribution Intermediate Disturbance Hypothesis Island biogeography Landscape ecology Landscape epidemiology Landscape limnology Metapopulation Patch dynamics r/K selection theory Source–sink dynamics Niche Ecological niche Ecological trap Ecosystem engineer Environmental niche modelling Guild Habitat Marine habitats Limiting similarity Niche apportionment models Niche construction Niche differentiation Other networks Assembly rules Bateman's principle Bioluminescence Ecological collapse Ecological debt Ecological deficit Ecological energetics Ecological indicator Ecological threshold Ecosystem diversity Emergence Extinction debt Kleiber's law Liebig's law of the minimum Marginal value theorem Thorson's rule Xerosere Other Allometry Alternative stable state Balance of nature Biological data visualization Constructal theory Ecocline Ecological economics Ecological footprint Ecological forecasting Ecological humanities Ecological stoichiometry Ecopath Ecosystem based fisheries Endolith Evolutionary ecology Functional ecology Industrial ecology Macroecology Microecosystem Natural environment Regime shift Systems ecology Theoretical ecology List of ecology topics