Alkalinity and total carbonate in sea water. A plea for p-T-independent data

It is shown, by a practical example, how Gran’s graphical method can be applied to an emf titration of a sea water sample with acid. From a single emf titration one may determine both the total alkalinity, A_t, and the total carbonate concentration, C_t. These quantities, if expressed in the unit M_w = mole/kg sea water, are both independent of p and T of the sample in situ and during the titration, which is an advantage in comparison with the traditional determination of pH only, or of pH and A_t.

The use of normalized values A_n and C_n, referred to a normal total halogenide concentration X_n, is suggested; A_n seems more convenient than the specific alkalinity used earlier. By studies of the variation of A_t and C_t with space and time one might follow chemical changes in a sea water mass, especially dissolution of, or losses of, CaCO₃ and CO₂, and ion exchange with clay minerals.