Biology - Decay and the Carbon Cycle

Decay is an essential life process whereby food and waste is digested and materials are recycled. Detritus feeders (eg. earthworms) may start the process of decay by eating dead animals or plants and producing waste materials. Decay organisms (bacteria and fungi) break down waste and dead organisms by releasing enzymes that break down compounds.

Factors affecting decay:

• moisture
• temperature
• available oxygen

Microorganisms are more active and digest materials faster in warm, moist and aerobic conditions.

All of the materials from waste and dead organisms are recycled as the decay process releases substances needed by plants for healthy growth.

The constant cycling of carbon is called the carbon cycle.

• CO2 is removed from the environment by green plants and algae during photosynthesis
• Carbon from CO2 is used to make carbohydrates, lipids and proteins which make up body of plants and algae
• When green plants and algae respire, some of this carbon becomes CO2 and is releades
• When green plants and algae are eaten by animals, and thee animals are eaten, some of the carbon becomes part of biological molecules that make up their bodies
• When animals respire, some of this carbon becomes CO2 and is released 
• When plants, algae and animals die, microorganisms feed on their bodies. When they respire, CO2 is released
• Combustion of wood and fossil fuels releases CO2 into atmosphere