What is the Carbon Cycle?

Oceans and land surfaces have been exchanging carbon dioxide with the atmosphere for billions of years. Oceans play an important role in capturing carbon dioxide, which is stored by shells in sediment. In the terrestrial carbon cycle, living organisms release carbon dioxide, which is fixed in the biomass through photosynthesis. The amount of “dead” biomass, represented by coal, oil or gas, exceeds that of "living" biomass by two to one. Video animation