Die Küste, 74 ICCE (2008), 31-44 
37 
3. Baltic Sea 
The Baltic Sea is the second largest brackish water body in the world. For its ecosystem, 
the Drodgen Sill in the 0resund and the Darss Sill between Gedser Rev and Fischland-Darss, 
with depth of only 7 m and 18 m, respectively, below Mean Water Level (MWL) are the most 
important features (Fig. 5). These sills control the water exchange with the North Sea, which 
is not continuous, but depends strongly upon westerly storms. This results in oxygen-rich 
North Seawater inflow into the Baltic Sea basin, 73 % of which pass via the Darss Sill (Jacob 
sen, 1980), whilst the remainder goes over the Drodgen Sill. 
The Baltic Sea is a very ‘young’ brackish water environment, which is extremely diverse 
compared to other seas regarding geological prerequisites, physical forcing of sediment mo 
bility and environmental conditions. Due to its young geological history and the on-going 
uplift and subsidence processes (Schwarzer et al., 2008, this volume), the surface sediment 
distribution and the upper part of the subsurface are very patchy; they are mainly of Quater 
nary origin. Particularly, compared to the tide-dominated North Sea, the surficial sediment 
distribution in the non-tidal Baltic Sea is much more heterogeneous; it is patchy on both, 
small and large spatial scales. This observation is confirmed by different maps (Fig. 6 and 7), 
for example Tauber and Lemke (1995), Tauber et al. (1999), Hermansen and Jensen (2000). 
The deep basins function as sinks for fine-grained sediments (silt and clay), whilst sandy 
material is deposited in the more shallow areas. Relict sediment remains, where till or other 
glacial deposits pinch out at the seafloor and are directly affected by waves. 
Fig. 5: Seabed Morphology of the South-western Baltic Sea including localities mentioned in the text. 
(Source: CONTIS [BSH])