A 300,000 year record of cold-water coral mound build-up in the SE Alboran Sea (western Mediterranean): insights from benthic foraminifera

Little is known about the build-up of Mediterranean cold-water coral mounds at the scale of multiple interglacial-glacial cycles. This study concentrates on the long-term development of coral mounds within the East Melilla Coral Province (Southeast Alboran Sea) and exposes how the distribution of benthic foraminiferal assemblages can provide key palaeoenvironmental information about the long-term processes driving coral mound development. The multiproxy investigation of core MD13-3462G reveals that mound build-up took place during both interglacial and glacial periods, at average aggradation rates ranging between 1 and 10 cm.kyr-1. These observations imply that corals never thrived but rather developed under stressful environmental conditions. High abundances of infaunal benthic foraminifera (Bulimina marginata, Bulimina striata and Uvigerina mediterranea) suggest that weak seafloor oxygenation associated to important terrestrial organic matter input characterized interglacial periods, whilst the dominance of large epibenthic species (Discanomalina coronata and Lobatula lobatula) and Miliolids is probably linked to stronger Levantine Intermediate Water circulation and fresher organic matter input during glacial periods. Glacial periods are further characterized by peak abundances of the erect branching bryozoan species Buskea dichotoma. Moreover, planktonic (Globigerina bulloides) and benthic (Lobatula lobatula) δ18O records show typical interglacial-glacial variations during the last two interglacial-glacial cycles. This is in contrast with δ18O records generally recovered from coral mounds in the Atlantic and implies that the northern part of Brittlestar Ridge I experienced reduced albeit relatively continuous accretion.