where, * CT is the total inorganic carbon * [CO2*] is the sum of carbon dioxide and carbonic acid concentrations ( [CO2*] = [CO2] + [H2CO3]) * [HCO3−] is the bicarbonate concentration * [CO32−] is the carbonate concentration Each of these species are intimately related by the following pH driven chemical equilibria: CO2 + H2O H2CO3 H+ + HCO3− 2H+ + CO32−