text: Full article: Solubility pump
  The oceans store the largest pool of reactive carbon on the planet as DIC, which is introduced as a result of the dissolution of atmospheric carbon dioxide into seawater – the solubility pump. Aqueous CO, carbonic acid, bicarbonate ion, and carbonate ion concentrations comprise dissolved inorganic carbon (DIC). DIC circulates throughout the whole ocean by Thermohaline circulation, which facilitates the tremendous DIC storage capacity of the ocean. The chemical equations below show the reactions that CO undergoes after it enters the ocean and transforms into its aqueous form.
  Carbonic acid rapidly dissociates into free hydrogen ion (technically, hydronium) and bicarbonate.The free hydrogen ion meets carbonate, already present in the water from the dissolution of CaCO, and reacts to form more bicarbonate ion.The dissolved species in the equations above, mostly bicarbonate, make up the carbonate alkalinity system, the dominant contributor to seawater alkalinity.