Carbon leaves the hydrosphere and enters the geosphere when sedimentary rocks form on the ocean floor. Ocean water can warm and release dissolved CO2 directly into the atmosphere. As carbon moves through Earth systems, the total amount of carbon in the carbon cycle remains about the same.
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone.
