Distribution of nine cold-water coral species (Scleractinia and Gorgonacea) in the cold temperate North Atlantic: effects of bathymetry and hydrography

The distribution of nine cold-water corals in the cold temperate North Atlantic is described based on existing records. The species studied are Lophelia pertusa, Madrepora oculata, Paragorgia arborea, Primnoa resedaeformis, Paramuricea placomus, Acanella arbuscula, Isidella lofotensis, Radicipes gracilis and Acanthogorgia armata. The compiled number of records were 5,854, of which 4,875 were obtained from databases and 979 from publications. Distribution maps were produced and temperature, broad-scale topography and current patterns were considered to understand the distribution patterns and conditions at which the species thrive. Currents connecting shelves and slopes above 500 m can explain the wide spatial distribution of L. pertusa, P. arborea and P. resedaeformis. However, L. pertusa is scarce on the western side of the North Atlantic, P. arborea has only few records off Iceland and A. arbuscula and A. armata are not found on the Norwegian shelf. The differences in distribution patterns between species indicate that they are differently affected by the topographic barrier between the North Atlantic and the Nordic Seas. Present knowledge of dispersal ability of cold-water corals does not allow a firm causal explanation to the observed distribution patterns. These, however, are indicative of biogeographic provinces relevant to cold-water corals and their habitat requirements.