The West Melilla cold water coral mounds, Eastern Alboran Sea: Morphological characterization and environmental context

A new mound field, the West Melilla mounds, interpreted as being cold-water coral mounds, has been recently unveiled along the upper slope of the Mediterranean Moroccan continental margin, a few kilometers west of the Cape Tres Forcas. This study is based on the integration of high-resolution geophysical data (swath bathymetry, parametric sub-bottom profiler), CTD casts, Acoustic Doppler Current Profiler (ADCP), ROV video and seafloor sampling, acquired during the TOPOMED GASSIS (2011) and MELCOR (2012) cruises. Up to 103 mounds organized in two main clusters have been recognized in a depth range of 299–590 m, displaying a high density of 5 mounds/km2. Mounds, 1–48 m high above the surrounding seafloor and on average 260 m wide, are actually buried by a 1–12 m thick fine-grained sediment blanket. Seismic data suggest that the West Melilla mounds grew throughout the Early Pleistocene–Holocene, settling on erosive unconformities and mass movement deposits. During the last glacial–interglacial transition, the West Melilla mounds may have suffered a drastic change of the local sedimentary regime during the late Holocene and, unable to stand increasing depositional rates, were progressively buried. At the present day, temperature and salinity values on the West Melilla mounds suggest a plausible oceanographic setting, suitable for live CWCs. Nonetheless, more data is required to groundtruth the West Melilla mounds and better constrain the interplay of sedimentary and oceanographic factors during the evolution of the West Melilla mounds.