Terrestrial biological carbon cycle

The carbon cycle is an essential part of life on Earth. About half the dry weight of most living organisms is carbon. It plays an important role in the structure, biochemistry, and nutrition of all living cells. Living biomass holds about 550 gigatons of carbon, most of which is made of terrestrial plants (wood), while some 1,200 gigatons of carbon are stored in the terrestrial biosphere as dead biomass.

Carbon is cycled through the terrestrial biosphere with varying speeds, depending on what form it is stored in and under which circumstances. It is exchanged most quickly with the atmosphere, although small amounts of carbon leave the terrestrial biosphere and enter the oceans as dissolved organic carbon (DOC).