Reply on RC2

Abstract

This study provides a detailed reconstruction of cold-water coral mound build-up within the East Melilla Coral Province (Southeast Alboran Sea) over the last 300 ky. Based on benthic foraminiferal assemblages, macrofaunal quantification, grain size analysis, sediment geochemistry, and foraminiferal stable isotope compositions, a reconstruction of environmental conditions having prevailed in the region is proposed. The variations in planktonic and benthic δ18O values indicate that cold-water coral mound build-up follows and records global climate variability. In contrast to northeast Atlantic counterparts, coral mound build-up in the southeast Alboran Sea occurs during glacial as well as during interglacial periods and at very low aggradation rates (between 1 and 10 cm.ky−1). Environmental conditions during glacial periods, particularly during the Last Glacial Maximum, appear to better suit the ecological requirements of the erect cheilostome bryozoan Buskea dichotoma. We propose that Buskea dichotoma has an important role in the build-up of cold-water coral mounds at the East Melilla Coral Province during glacial periods. Benthic foraminiferal assemblages suggest that important terrestrial input favoured cold-water coral proliferation during interglacial periods. The existence of strong Alboran Gyres during interglacial periods, promoting mixing between surface and intermediate water masses and bottom water turbulence, was possibly beneficial for cold-water coral development. Conversely, benthic foraminiferal assemblages indicate that the seafloor received less organic matter during glacial periods. Overall, the arid continental conditions combined to more stratified water masses resulted in limited coral proliferation during glacial times.