The carbon cycle describes the exchange of carbon between the different spheres of the Earth

• Different processes facilitate the cycling of carbon between these spheres (e.g. feeding, combustion, etc.)
  

Carbon is cycled in a variety of different forms, including:

• Atmospheric gases – The main gas is carbon dioxide (CO2) but methane (CH4) may also be produced
  

• Oceanic carbonates – Including bicarbonate ions (dissolved in the water) and calcium carbonate (in corals and shells)
  

• Organic biomass – Stored within living tissues as either carbohydrates, lipids, proteins or nucleic acids
  

• Detritus – Carbon compounds may accumulate within the soil and form fossil fuels (oil, coal or natural gas)

Carbon Cycle