The only community described is Lophelia pertusa, a cold water, reef-forming coral, which has a wide geographic distribution ranging from 55°S to 70°N, where water temperatures typically remain between 4-8°C. These reefs are generally subject to moderate current velocities (0.5 knots). The majority of records occur in the north-east Atlantic. The extent of L. pertusa reefs varies, with examples off Norway several km long and more than 20 m high. These reefs occur within a depth range of 200 - >2000 m on the continental slope, and in shallower waters in Norwegian fjords and Swedish west coast. In Norwegian waters, L. pertusa reefs occur on the shelf and shelf break off the western and northern parts on local elevations of the sea floor and on the edges of escarpments. The biological diversity of the reef community is approximately three times as high as the surrounding soft sediment (ICES, 2003), suggesting that these cold-water coral reefs may be biodiversity hotspots. Characteristic species include other hard corals, such as Madrepora oculata and Solenosmilia variabilis, the redfish Sebastes viviparous and the squat lobster Munida sarsi. L. pertusa reefs occur on hard substrata; this may be Lophelia rubble from an old colony or on glacial deposits. For this reason, L. pertusa reefs can be associated with iceberg plough-mark zones.
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