The Giant Cold-Water Coral Mounds Barrier off Mauritania

Resumo

This chapter describes the main features of the giant mounds structure running parallel to the shelf break along the Mauritanian slope between the Senegalese border and Cape Timiris. At over 580 km long, it is the world's largest identified cold-water coral mounds barrier and, in our opinion, conforms to a single province, the Mauritanian Province. The Maurit series of Spanish-Mauritanian oceanographic surveys collected multibeam echosounder data, performed 16 conductivity-temperature-depth (CTD) profiles and 13 rock dredge samplings, which led to the mapping of the reef complex, oceanographic characterization of water masses and faunistic studies. The reef framework is mostly composed of dead coral, mainly Lophelia pertusa, with a minor fraction of Madrepora oculata. Associated fauna mainly consists of Acesta excavata and other bivalve and prosobranch molluscs, soaked in abundant, fine compacted mud. At least 150 macrobenthic species of 27 high-range taxa inhabit this reef. The coral surface is either almost devoid of sessile fauna or poorly colonized by small encrusting epifaunal species. We only found fragments of living L. pertusa in the four southernmost stations. The multivariate analysis clearly groups some areas where corals and other suspension-feeders exhibit the highest diversity. Despite their small size, the 17 taxa of suspension-feeders represent 75% of abundance and biomass Surprisingly, despite the unfavourable history of climatic change episodes, current environmental conditions, deterioration and overall faunistic poverty of the mounds, Lophelia specimens still survive in some areas, sheltering communities of apparently similar structure to those on well-developed cold-water coral reefs in Northern Atlantic latitudes.