On biogenic elements and organic matter in the Baltic

Abstract

The water exchange of the Baltic is restricted through the narrow and shallow entrance area. The positive water balance causes stagnant conditions in the deep water. In such semi-enclosed basins the oxygen content of the deep water is depleted and nutrients are accumulated there. The oxygen deficiency is caused by oxidation of organic matter in the water. Nutrient salts are formed through transformation into inorganic form of organically bound nutrient elements. Therefore the supply of organic matter and the oxidation rate are the main factors which regulate the oxygen conditions in deep water, beside the water exchange ratio in the Danish sounds.