Ship wake induced seabed modification in the Baltic Sea

The Baltic Sea is one of the busiest marine regions in terms of commercial shipping. Increased marine traffic over the last decades already led to increased number of bigger ships and more powerful propulsions systems. This development has put a number of environmental effects of shipping, such as air pollution, marine noise or accidental discharges of hazardous substances, on the discussion list. What has, however, only marginally been studied is the possible effect of commercial shipping on sedimentation patterns and seafloor morphology. Here we use AIS data from the last 20 years to identify hotspots of marine traffic in the Baltic Sea. Subsequently we collect multibeam bathymetric data from different sources and databases to investigate seafloor morphology in some traffic hotspots. We further collect seabed sediment samples and time-lapse bathymetric data in the Bay of Kiel, where Kiel Canal, one of the most heavily used artificial waterways on the globe, commences. First results indicate that ships can erode hard substrate such as basal till, most likely through interaction of their wake with the seafloor. In addition to eroding the hard seafloor, the wakes may also mobilize and locally redistribute mobile sands.