Decomposers are living organisms, so the rate at which they recycle nutrients depends on the conditions they need to grow and respire. Decomposition is fastest when conditions suit their enzymes.- Temperature: warmth increases the rate of enzyme-controlled reactions, so decomposition is faster in warm conditions. Very high temperatures denature enzymes. In cold places such as the Arctic tundra, decomposition is very slow.
- Water: decomposers need water for their reactions and to absorb dissolved food. Dry conditions slow decomposition, which is why dried food keeps well.
- Oxygen: most decomposers respire aerobically. In waterlogged soils there is little oxygen, so decomposition slows and dead plant material builds up as peat.
- pH: very acidic conditions, such as in bogs, slow most bacteria.
- Surface area: small pieces are broken down faster, so detritivores and shredding speed up decomposition.
- Numbers of decomposers and detritivores present.Gardeners use these conditions in a compost heap: it is kept moist, warm (heat from respiration builds up inside) and turned regularly to let in oxygen.Worked example: a litter bag containing 10 g of dry leaves is buried in a wood. After three months, 6 g remain.percentage mass lost = (10 − 6) ÷ 10 × 100 = 40% The same bag buried in a colder or drier site would lose a smaller percentage in the same time.
- Water: decomposers need water for their reactions and to absorb dissolved food. Dry conditions slow decomposition, which is why dried food keeps well.
- Oxygen: most decomposers respire aerobically. In waterlogged soils there is little oxygen, so decomposition slows and dead plant material builds up as peat.
- pH: very acidic conditions, such as in bogs, slow most bacteria.
- Surface area: small pieces are broken down faster, so detritivores and shredding speed up decomposition.
- Numbers of decomposers and detritivores present.Gardeners use these conditions in a compost heap: it is kept moist, warm (heat from respiration builds up inside) and turned regularly to let in oxygen.Worked example: a litter bag containing 10 g of dry leaves is buried in a wood. After three months, 6 g remain.