Read Detritus from Breakdown to Humus
Decomposition recycles nutrients by breaking detritus down through overlapping physical, chemical and microbial steps.
Living-system questions are solved by matching a structure or organism to its function, process and stated condition.
Follow the process
Fragmentation, leaching, catabolism, humification and mineralisation can overlap. Decomposition is largely aerobic. Its rate depends on detritus chemistry and climate: warmth, moisture and oxygen favour microbial activity; cold and anaerobiosis slow it.
Understand humus
Humus is dark, amorphous, colloidal and hydrophilic. It resists rapid breakdown and stores water and nutrients, but is not immune to all microbial action. It remains partially decomposed organic matter.
Predict litter accumulation from climate
Warm, moist tropical conditions favour rapid microbial and detritivore activity, so litter decomposes quickly and little dead organic matter accumulates on the forest floor. Cold, dry, or oxygen-poor conditions slow decomposition and tend to leave more litter standing.
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- ✓Decomposition is largely aerobic.
- ✓Warm, moist, oxygenated conditions speed it.
- ✓Humus: amorphous, colloidal, water/nutrient retaining.
- ✓Leaching, fragmentation and catabolism can overlap.
Humus is resistant, not indestructible.
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