The total inorganic carbon (CT, or TIC) or dissolved inorganic carbon (DIC) is the sum of inorganic carbon species in a solution. The inorganic carbon species include carbon dioxide, carbonic acid, bicarbonate anion, and carbonate.[1] It is customary to express carbon dioxide and carbonic acid simultaneously as CO2* . CT is a key parameter when making measurements related to the pH of natural aqueous systems,[2] and carbon dioxide flux estimates.
(Wikipedia)