Carbon in the environment form the carbon cycle. For example, photosynthetic plants draw carbon dioxide from the atmosphere (or seawater) and build it into biomass, as in the Calvin cycle, a process of carbon fixation. Some of this biomass is eaten by animals, while some carbon is exhaled by animals as carbon dioxide. The carbon cycle is considerably more complicated than this short loop; for example, some carbon dioxide is dissolved in the oceans; if bacteria do not consume it, dead plant or animal matter may become petroleum or coal, which releases carbon when burned. Carbon can form very long chains
Carbon dioxide clathrate becomes clear that all the above-mentioned speculations rest on extremely unstable bases. On Enceladus decomposition of carbon dioxide clathrate is a possible way to explain the formation of gas plumes. In Europa (moon), clathrate should be important for storing carbon dioxide. In the conditions of the subsurface ocean in Europa, carbon dioxide clathrate should sink, and therefore not be apparent at the surface. The hydrate structures are stable at different pressure-temperature conditions depending on the guest molecule. Here is given one Mars-related phase diagram of CO hydrate, combined with those of pure CO and water (Genov 2005). CO hydrate has