5.4 Carbon cycle
The Carbon Cycle
The amount of carbon on Earth is fixed and some carbon is locked up in fossil fuels, oil, coal and gas and is only released when burned. When carbon is released and locked up we call this the carbon cycle.
Green plants photosynthesise and use the carbon in CO2 to make carbohydrates, fats and protein. The carbon is passed onto animals when they eat the plant. This is how carbon is taken out of the environment.
Living organisms respire, this break down glucose with oxygen to produce energy in their cells and carbon dioxide is released as a waste material.
Detritus feeders break down dead animals and respire at the same time.
Combustion - something is burned with the presence of oxygen and when coal, oil or gas is burned, carbon dioxide is produced from the locked up carbon in the fossil fuels.