The Carbon Cycle
• The Carbon Cycle: A sequence of processes by which carbon moves from the atmosphere, through living and dead organisms, into sediments and into the atmosphere again.
• The only way carbon dioxide is removed from the atmosphere is by photosynthesis – and there are numerous ways it returns to the atmosphere.
• Eating passes the carbon compounds in the plant along to animals in a food chain or web.
• Both plant and animal respiration put carbon dioxide back into the atmosphere.
• Plants eventually die and decay and decomposer microorganisms such as bacteria and fungi feed on them. When they respire they release carbon dioxide back into the air.
• Fossil fuels (made of decayed plant and animal matter), when burned, release carbon dioxide into the air.
Nutrients are constantly recycled
• Living things are made of elements they take from the world around them. Plants not only take carbon from the environment but also take oxygen, hydrogen and nitrogen from the soil or air. These elements are formed into complex compounds that make up living organisms.
• The elements are returned to the environment as waste products produced by the organisms, or when the organisms die. Dead organisms decay because they’re broken down by decomposers, and the elements are put back into the soil.
• All the important elements are recycled – they return to the soil or air, ready to be used by new plants and put back into the food chain.