DISSOLVED INORGANIC CARBON AND TOTAL ALKA LINITY IN ANOXIC WATERS OF THE BLACK-SEA

The heavy continental freshwater outflow and the hydrological structur e of the Black Sea lead to considerable rise of inorganic carbon and n utriance elements contain in the deep waters of the Black Sea in compa rison with the corresponding deep waters of the World Ocean. Peculiari ties of chemical composition of the Black Sea waters lead to the diffe rence in the correlation of various components of total alkalinity in comparison with ocean waters. This fact must be taken into considerati on when one calculates the components of the carbon system from total alkalinity together with the pH value or TCO2 quantity. For the anoxic Black Sea waters it is not sufficient to present the total alkalinity as the sum of boron and carbonate components. Deeper than 200 meters the hydrosulphide, silicate and ammonium alkalinity values are equal t o the boron and considerably surpass it in the deep waters. The relati ve value of the boron alkalinity in the deep water is so little (about 0.3% from the total alkalinity) that it may not be taken into conside ration. If the ions of hydrogen sulphide, ammonium, orthosilicate and orthophosphoric acid are not taken into consideration a calculation er ror of the carbon system in the anoxic Black Sea waters can reach 11%. The analysis of the vertical distribution of dissolved inorganic carb on and its comparison with the distribution of hydrogen sulphide and a mmonium show that its depth dependence increases greater than it can b e explained only by the microbial transformation of sulfur and ammoniu m formation.