Study reveals Baltic Sea impacts of ship wakes - How Massive Ships Are Reshaping the Baltic Sea's Fragile Seafloor

Ship traffic in the Baltic Sea is causing growing concern over its impact on the marine environment. Large vessels create powerful wakes that disturb the water column and erode the seafloor. These changes are now being observed in heavily trafficked regions, raising questions about long-term ecological effects.

The movement of big ships generates turbulence that reaches depths of 12 to 16 metres. This disrupts the natural layering of water, altering how oxygen, nutrients, and trace elements move between surface and deeper levels. Over time, the mixing process changes the chemical balance of the sea.

Propellers produce strong shear forces that shift sediments, sometimes carving depressions into the seabed. In busy shipping lanes, erosion can strip away the seafloor in bands up to 60 metres wide. The disturbed material often contains organic matter, trapped pollutants, and nutrients, which then spread through the water.

Studies in the North Sea and Mediterranean show similar problems, with 20-40% of seafloor areas in major routes affected by mechanical disturbance over the last five years. While data collection methods vary, the western Baltic Sea—one of the busiest regions—faces particularly severe turbulence from passing vessels.

The ongoing erosion and sediment resuspension are degrading marine habitats in high-traffic zones. As ship activity continues, these disturbances could further alter water quality and seabed stability. Researchers are now focusing on better measuring the scale and long-term consequences of these changes.