Low vulnerability of the Mediterranean antipatharian Antipathella subpinnata (Ellis & Solander, 1786) to ocean warming

Antipatharians (black corals) are major components of mesophotic ecosystems in the Mediterranean Sea. The arborescent species Antipathella subpinnata has received particular attention as it is most abundant and forms dense forests harbouring high levels biodiversity. This currently categorized “Near Threatened” IUCN Red List, due to increasing fishing pressure bottom-trawling activities. Yet, effects ocean warming have never been investigated for this species, nor any other antipatharians from temperate regions. Our study aimed at evaluating seawater temperatures on A. subpinnata, by combining predictive distribution modelling with a physiological tolerance experiment. During latter, we exposed 15 days different temperature conditions spanning current seasonal range forecasted 2100, while measuring biological endpoints such oxygen consumption rates signs stress (tissue necrosis, total antioxidant capacity). Unexpectedly, no was found organism cellular level (wide thermal breadth) suggesting low susceptibility mid-term increase. If response 15-days heat representative longer-term warming, unlikely affect subpinnata. model predicted presence depths that correspond colder than its maximum (as determined physiology experiment). suggests shallower not limited constraints but ecological factors including interspecific competition.