Decomposition and nutrient cycling
Animals fragment and consume litter, while fungi, bacteria, and other microbes use enzymes to break complex molecules down. Some carbon enters decomposer biomass or soil and some is respired; nitrogen, phosphorus, and other elements can be immobilized, transformed, released, transported, and taken up again.
Scope: A worldwide overview of how dead organic matter is fragmented, chemically transformed, respired, leached, and incorporated into food webs in terrestrial and aquatic ecosystems. Rates and pathways vary strongly with material quality, temperature, moisture, oxygen, decomposer communities, and hydrology. · Last updated
Dead matter supports a living food web
A fallen leaf or log is not processed by one universal decomposer. Detritivores fragment and ingest material, fungi extend hyphae and secrete enzymes, and bacteria transform accessible compounds. Their consumers form a detrital food web. Physical abrasion, freezing, drying, and leaching also alter material, so decomposition combines biological activity with the conditions surrounding the litter. [1][2][5]
Carbon and mineral nutrients take different routes
Decomposers use organic carbon for growth and respiration; some becomes microbial biomass or remains in soil and sediment, while some returns to the atmosphere as carbon dioxide or, under oxygen-poor conditions, methane. Nitrogen and phosphorus may be held temporarily in organisms, converted among chemical forms, released as inorganic nutrients, carried away, or taken up by plants and microbes again. [3][4][6]
Rate depends on material and environment
Soft, nutrient-rich tissues generally decompose more readily than wood or litter rich in lignin and defensive compounds. Temperature, moisture, oxygen, soil chemistry, organism access, and decomposer identity all matter. Warmth can accelerate reactions only while water, oxygen, and suitable substrate remain available; flooding may slow some aerobic pathways while enabling different microbial processes. [2][4][5]
Streams move the products downstream
In water, leaves and wood can be colonized, shredded, leached, buried, retained, or exported. Flow links local breakdown to downstream transport, while microbes associated with submerged litter can take up or mineralize nitrogen and phosphorus as decomposition proceeds. A bare-looking log can remain part of a stream's organic-matter storage and food web while also changing flow and trapping leaves. [5][6]
Related guides
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Where this guide comes from
Source-checked editorial guide. Last updated . This guide teaches identification and field skills; it is not a substitute for expert verification when it matters.
- USDA Natural Resources Conservation Service — Biological Underground Community ↗
- Proceedings of the National Academy of Sciences of the United States of America — Substrate and climate determine terrestrial litter decomposition ↗
- Ecological Monographs — Stoichiometric controls on carbon, nitrogen, and phosphorus dynamics in decomposing litter ↗
- Annals of botany — Methane emission from natural wetlands: interplay between emergent macrophytes and soil microbial processes. A mini-review ↗
- TheScientificWorldJournal — From litterfall to breakdown in streams: a review ↗
- Freshwater Science — Immobilization and mineralization of nitrogen and phosphorus during leaf decomposition ↗
