Biogeography

Cold-water scleractinian reefs have a widespread distribution and are located from high to low latitudes within all of the major oceanic basins (Fig.2.) (Roberts et al.,2009). Globally, cold-water reefs are comprised of different species depending on location. Lophelia pertusa and Madrepora oculata have cosmopolitan distributions in the north-east and western Atlantic (Rogers, 1999; Álvarez-Pèrez et al., 2005; Shroeder et al., 2005), whereas Lophelia pertusa is also found in the Pacific and Indian Oceans but is more limited (Etnoyer and Morgan, 2005). Solenosmilia variabilis is similar in distribution to L. pertusa except that it is absent in the north and eastern Atlantic, and Antarctica (Cairns, 2007). Oculina varicosa is concentrated in the northwest of the Atlantic, along the east coast of Florida, down to the Caribbean and Gulf of Mexico (Reed, 2002). Goniocorella dumosa is only common in the Pacific and Indian oceans, with aggregations on seamounts off New Zealand (Probert, 1999). Enallopsammia profunda is found only in the Western Atlantic but occurs with L. pertusa, Solenosmilia variabilis and M. oculata (Reed, 2002).

New reefs are still being discovered and recent studies have identified scleractinian reefs in the Gulf of Cadiz (Wienberg et al., 2009) and on the Angola Margin, off the west coast of Africa (Le Guilloux et al., 2009). Research bias within developed countries tends to skew distribution patterns (Roberts et al., 2009), hence global distribution is likely to be greater than current evidence suggests especially in areas such as the Indian Ocean (Davies et al., 2008). Cold-water reefs occur on a variety of geological features: seamounts, ridges, canyon walls, continental slopes and shelf margins (Probert, 1999; De Mol et al., 2002, Mortensen and Buhl-Mortensen, 2005). The size of the reefs  at these locations can vary from small Oculina colonies, several meters across (Reed, 2002) to reefs such as the Røst reef, which is 100 km² (Fosså et al., 2002). In terms of depth, reefs have been found at depths from 50 to 1000 m with some as deep as 4000m (Freiwald et al., 2004).

Fig.2. The global distribution of cold-water coral reefs. Reproduced from Freidwald et al.,(2004)

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