Report | July 7, 2026
Environmental and geomorphological drivers of the distribution of black corals across an oceanic archipelago and adjacent seamounts from the eastern Atlantic
Abstract
Oceanic archipelagos host unique biodiversity shaped by strong geomorphological and oceanographic gradients. The Canary Islands and their adjacent seamounts is a biodiversity “crossroad” between the Atlantic and Mediterranean biogeographic zones, spanning ca. 1,300 km from the western to the eastern islands. Here, we took advantage of this geomorphological configuration to assess whether the distribution patterns of black corals (Anthozoa, Antipatharia) varied across island groups (i.e. western, central, eastern, and seamounts) in relation to key environmental and geomorphological drivers. Occurrences of antipatharians were compiled from SCUBA surveys, towed cameras and ROV deployments conducted across 144 sites and depths from 1 to ca. 1,000 m. Over 2,400 presence records were obtained, including 11 taxa from 10 genera. Black coral assemblages showed clear bathymetric partitioning, with some taxa mainly restricted to mesophotic depths, others occurring predominantly in bathyal waters, and Stichopathes spp. and Leiopathes sp. spanning broader depth ranges. Depth and substrate type were the main predictors of the distribution of most common taxa (Antipathella wollastoni, Antipathes furcata, Parantipathes spp. and Stichopathes spp.), while horizontal current speed, vertical velocity, slope and island group also influenced their occurrences. A. wollastoni and A. furcata were strongly associated with hard substrates at mesophotic depths, whereas Parantipathes spp. was more frequent in bathyal habitats and positively related to horizontal current speed. These findings provide predictive insights into the distribution patterns of black coral taxa in relation to diverse environmental and geographical factors, revealing the significance of this region as an important global hotspot, and providing essential baseline information for the sustainable management and protection of mesophotic and deep-sea coral-dominated ecosystems
