Azooxanthellate Madracis coral communities off San Bernardo and Rosario Islands (Colombian Caribbean)

摘要

Azooxanthellate habitat-forming corals develop in deep waters adjacent to shallow fringing coral reefs off San Bernardo and Rosario Islands (Colombian Caribbean). This study was carried out to characterize biological and geological features of the continental margin where these azooxanthellate coral communities flourish. The principal habitat-forming corals species found were Madracis myriaster (Milne-Edwards and Haime, 1849) and other branching Madracis species. These communities rest on sandy mud bottoms over the shelf break, in depths ranging from 120-180 m. Madrepora sp., antipatharians, and gorgonians were collected directly attached to adjacent limestone hardgrounds. The azooxanthellate coral habitats were found on areas of irregular topography (channels, small mounds) and nearby sites with evidence of benthic mud-gas seepage from beneath the seafloor. Irregular topography and gas seeps might be important factors contributing to the settlement and accumulation of coral communities, but the mechanisms involved are not fully understood. Questions remain pertaining to the possible linkage between shallow- and deep-water corals in the Caribbean region.