Coastal features of the Baltic Sea
There are chalk cliffs on the island of Rügen
Image: Johannes Schröder
1 - As on all seas, we find many different types of coastline on the Baltic Sea. In the northern Baltic, off Finland and Sweden, you find the skerry coast. Skerries are small rocky islands that were worn smooth by the glaciers of the ice ages. When the ice melted, the lower-lying coastal areas were flooded. The higher ground remained, now rising out of the water as small islands.
Skerries off the Åland Islands (Sweden)
Image: public domain
2 - The influence of the Ice Ages also led to the formation of fjords. These are long, shallow sea inlets found mainly along the Danish and German Baltic coasts. Well-known examples include Kiel Fjord, the Schlei and Lübeck Bay. They are former valleys shaped by Ice Age glaciers. As the climate warmed and the glaciers melted, the valleys filled with seawater.
The Schlei in Schleswig-Holstein was shaped by glaciers
Image: Hamsterkiste
3 - In other places, we find steep, crumbling coasts. These are called cliff coasts . The most famous example is the chalk cliffs on Rügen. The constant pounding of the water wears away the lower rock layers. This undercuts parts of the coast, and eventually the overhanging cliffs collapse into the sea.
On steep coasts, rock layers are eroded and overhanging cliffs break off
Image: Johannes Schröder
4 - The Baltic coast also has equilibrium coasts. Wind erodes the land in one place and deposits it elsewhere. This evens out the originally rugged coastline, giving it a straight course. For example, on the Polish Baltic coast lies the Vistula Lagoon. Sand deposits have formed a 70 km-long and 2 km-wide peninsula here, almost completely enclosing a former part of the Baltic Sea. The lagoon is still connected to the sea by a narrow channel.
The Vistula Lagoon near the town of Frombork in Poland
Image: Hamsterkiste
5 - Elsewhere along the Baltic coast, you come across bodies of water that could be mistaken for lakes. Small islands have formed here as sand deposits have connected them to the mainland or to larger islands. This cut off bodies of water from the Baltic Sea. They are called Bodden .
The water in the Bodden lagoons is very shallow. It contains even less salt than the Baltic Sea. Bodden lagoons provide a unique habitat for plants and animals. Examples include Achterwasser, south of the island of Usedom, and Greifswald Bay.
Achterwasser south of Usedom
Image: Hamsterkiste