ABSTRACT
The oceans are the ultimate carbon sink, and they have the largest role to play in bringing the carbon cycle back into balance over the coming centuries. The oceans help to regulate the balance of carbon between the three active carbon reservoirs (the atmosphere, the land, and the oceans). As the oceans contain nearly all (93%) of the exchangeable carbon, they will, in the long term, largely determine the equilibrium carbon dioxide (CO2) concentration in the atmosphere. Each year, large quantities of carbon (in the form of CO2) are exchanged between the atmosphere and the oceans, with annual carbon fluxes (exchanges) in the order of 90-100 gigatonnes (Gt).
