Stumbling threshold

Coordinates: 55 ° 22 ′  N , 16 ° 39 ′  E The Stolper Schwelle is an undersea threshold in the central Baltic Sea between Pomerania and the Swedish island of Öland .

It extends from the Stolpe-Bank north of Ustka , the former Stolpmünde, to the north and separates two lake basins of the Baltic Sea from each other, the up to 105 meter deep Bornholm Basin in the west from the Stolper Rinne, which runs north along the Stolpe-Bank, and thus from the eastern Gotland Basin with the Danzig Basin (110 m), the Gotland Deep (249 m), the Farötief (205 m) and the Riga Bay in the east.

With its saddle depth (deepest point) of 60 m, the Stolper Schwelle, like the Darßer Schwelle further west (18 m saddle depth) between Fischland-Darß-Zingst and Falster , hinders the exchange of water between the western and central Baltic Sea, namely the inflow of salt and water oxygen-rich deep water from the Kattegat and the North Sea . The consequence of this is that in the deep basins of the central and eastern Baltic Sea there are periods of stagnation with drastically decreasing salt and oxygen concentrations and, in some cases, drastic increases in hydrogen sulphide concentrations and thus extremely hostile conditions. These periods of stagnation can only be interrupted by the influx of larger amounts of salt-rich water from the North Sea, which are known as saltwater ingresses and lead to a renewal of the deep water.

literature

• Stefan Kraatz: Hydrography and water exchange in the Baltic Sea. (PDF; 345 kB). Geographical Institute of the University of Kiel, 2004.
• Susanne Unverzagt: Spatial and temporal changes in areas with oxygen deficiency and hydrogen sulfide in the deep waters of the Baltic Sea. (PDF; 4.4 MB). (= Greifswald Geographical Works. Volume 19). Geographical Institute of the Ernst Moritz Arndt University Greifswald, Greifswald 2001, ISBN 3-86006-166-6 .