Decomposition, often called 'rotting', is the process by which dead organic matter is broken down into simpler organic or inorganic substances, such as carbon dioxide, water, simple sugars, and minerals.

Detritus feeders - small animals like worms and woodlice that feed on dead organic matter.

Decomposers - microorganisms, such as bacteria and fungi.

1Oxygen availability

2Temperature

3Water content.

More oxygen ➔ more aerobic respiration ➔ more energy available ➔ faster growth and decomposition

Higher temperature ➔ particles have more kinetic energy & enzymes are closer to optimum temperature ➔ higher rate of reactions ➔ more decomposition

If the temperature rises too high, it will denature the enzymes in the decomposers, decreasing the rate of reaction and therefore decreasing the rate of decomposition.

Decomposers need water to survive, so the rate of decomposition increases in moist conditions.

1. 'Waterlogged' means that water has filled all the air gaps within the soil.

1. This means there will be less air and thus less oxygen in the soil.

1. This, in turn, will mean the decomposers will not be able to carry out as much aerobic respiration, which will mean fewer chemical reactions and thus slower decomposition.

Compost is a mixture of decayed organic material that is used to fertilise and improve the soil. 

Anaerobic decay is a type of decomposition done in the absence of oxygen, where microorganisms carry out anaerobic respiration.

Biogas generators are large containers in which animal or plant waste is left to decay anaerobically.

To preserve food means to stop it from being decomposed. 

1Store it at low temperatures e.g. put it in the fridge.

2Prevent it from being contaminated e.g. put it in a container.

3Remove the water from it before storing it.