Carbon cycle

What is the carbon cycle?

It is an example of natural recycling that involves the movement of carbon through dead & living organisms and the atmosphere

What are the stages of the carbon cycle?

• Photosynthesis

• Feeding

• Respiration

• Decomposition

• Fossilisation

• Combustion

Photosynthesis

Photosynthesis fixes inorganic carbon atoms from carbon dioxide into organic compounds

Feeding

Feeding and assimilation pass these carbon atoms now in organic molecules along food chains

Respiration

Respiration produces inorganic carbon dioxide from organic compounds (mainly carbohydrates) as they are broken down to release energy

Decomposition

Decomposition release carbon dioxide into air, soil and water during the breakdown of organic matter by micro-organisms like bacteria and fungi

Fossilisation

Fossilisation happens sometimes when living things do not decay fully when they die due to conditions in the soil (decay is prevented if the soil is too acidic) and fossil fuels like coal, oil and natural gas are formed.

Combustion

Combustion releases carbon dioxide into the atmosphere when fossil fuels are burned.

Carbon cycle visualised

What are the processes and human activities that add CO₂ to the atmosphere?

• Respiration

• Deforestation

• Ploughing

• Combustion of fossil fuels

• Decomposition of microorganisms

What are the processes and human activities that remove CO₂ to the atmosphere?

• Photosynthesis