Carbon cycle




The carbon cycle describes the fluxes of carbon dioxide (CO
2) between the oceans, terrestrial biosphere, lithosphere, and the atmosphere. Human activities such as the combustion of fossil fuels and land use changes have led to a new flux of CO
2 into the atmosphere. About 45% has remained in the atmosphere; most of the rest has been taken up by the oceans, with some taken up by terrestrial plants.

The carbon cycle involves both organic compounds such as cellulose and inorganic carbon compounds such as carbon dioxide, carbonate ion, and bicarbonate ion. The inorganic compounds are particularly relevant when discussing ocean acidification for they include many forms of dissolved CO
2 present in the Earth's oceans.

When CO
2 dissolves, it reacts with water to form a balance of ionic and non-ionic chemical species: dissolved free carbon dioxide (CO
2(aq)), carbonic acid (H
2CO
3), bicarbonate (HCO−
3) and carbonate (CO2−
3). The ratio of these species depends on factors such as seawater temperature, pressure and salinity (as shown in a Bjerrum plot). These different forms of dissolved inorganic carbon are transferred from an ocean's surface to its interior by the ocean's solubility pump.

The resistance of an area of ocean to absorbing atmospheric CO
2 is known as the Revelle factor.

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References

Clarke, L.; Edmonds, J.; Jacoby, H.; Pitcher, H.; Reilly, J.; Richels, R. (July 2007). "Scenarios of Greenhouse Gas Emissions and Atmospheric Concentrations. Sub-report 2.1A" (PDF) . In U.S. Climate Change Science Program and the Subcommittee on Global Change Research (ed.). Synthesis and Assessment Product 2.1 . Washington, DC., USA: Department of Energy, Office of Biological & Environmental Research. Archived from the original (PDF) on 16 June 2013. Good, P.; Gosling, S. N.; Bernie, D.; Caesar1, J.; Warren, R.; Arnell, N. W.; Lowe, J. A. (2010). An updated review of developments in climate science research since IPCC Fourth Assessment Report (PDF) (Report). London, UK: AVOID Consortium. Report website. UK Royal Society (September 2009). Geoengineering the climate: science, governance and uncertainty (PDF) . London: UK Royal Society. ISBN  978-0-85403-773-5 , RS Policy document 10/09. Report website. UNEP (November 2010). The Emissions Gap Report: Are the Copenh...
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