Sweden’s only remaining cold-water coral reef, the Säcken reef in the Koster Fjord, is under threat of extinction. Because of that, researchers from the University of Gothenburg have started a restoration project where healthy corals from nearby reefs in Norway are being removed and placed on the Säcken reef.
Coral reefs are known for their rich biological diversity. In Sweden, only one reef-building coral species exists, a cold-water coral called Lophelia pertusa. Lophelia pertusa requires an environment with a constant high level of salinity and low water temperatures all year round. In Sweden, these conditions only exist in the northern part of Bohuslän, where deep water from the Atlantic is led in via the Norwegian Trench.
“We’ve known since the mid-1920s that cold-water coral reefs exist here in Sweden,” says marine biologist and researcher Mikael Dahl. “At that time, corals could be found in three locations in the Koster Fjord. Today, only the Säcken reef remains, and it’s in poor condition.”