Hydrographic Conditions

Abstract

With an area of 422,000 km2, the Baltic Sea ranks between Hudson Bay (1, 232,000 km2) and the Black Sea (420,000 km2) as the second largest brackish sea in the world (cf. Seibold, 1970). From north to south it extends over 12 degrees of latitude from 66°N to 54°N and on the east-west axis from 30°E to 10°E. The average depth is 55 m and the total water volume approximately 23,000 km3. The Baltic Sea consists of a series of basins of varying depth, the deepest point lying in the Gotland Basin. The Kattegat and the Belt Sea, which comprise the transitional area between the Baltic and the North Sea, are comparatively shallow. A key role in water exchange here is played by sills 11-m, 26-m, and 8-m deep situated in the three straits Little Belt, Great Belt and Öre-Sund, respectively. Another sill, the so-called Darsse sill (18 m) lies between the Mecklenburg Bight and the Arkona Basin.