PREDICTING SUITABLE HABITATS AND REFUGIA FOR THE DEEP-SEA CORAL LOPHELIA PERTUSA, US WEST ATLANTIC AND NORTHERN GULF OF MEXICO

Deep-sea corals are a vital component of shelf and slope marine ecosystems but are vulnerable to anthropogenic threats. There is an ongoing research focus to better understand how increasing ocean temperatures, acidification, and deoxygenation will affect deep-sea coral species such as the important reef-builder Lophelia pertusa. This work updates predictions for suitable habitat and identifies specific refugia locations for Lophelia pertusa within US marine ecoregions in the US West Atlantic and Northern Gulf of Mexico. Modeled predictions use a resolution of 370 m² and are based on oceanic conditions for RCP 8.5 (representative concentration pathways, business-as-usual).

This study predicts that locations with currently favorable suitable habitat of Lophelia pertusa will decrease in suitable habitat by an average of 48.3% by 2050 and an average of 61.8% by 2090. Results herein support that suitable habitat loss for Lophelia pertusa will likely be driven by a combination of unfavorable changes in temperature, particulate organic carbon flux to seafloor, oxygen concentration, and pH. The 48.3% decrease by only 2050 highlights the importance of identifying and preserving refugia locations, especially because deep-sea corals exhibit slow growth and long recovery from ecosystem disturbances.

Previous models with broad resolution (3,000 m²) predicted no refugia for these ecoregions by 2090. The finer spatial scale of this study (370 m²) identified over 18,600 new locations of refugia for Lophelia pertusa by 2090 under RCP 8.5. Refugia locations for 2090 are not uniformly distributed across marine ecoregions, which may affect connectivity and dispersion potential of the species. The Florida/Bahamian Atlantic shows a lack of refugia compared to other ecoregions, which suggests that connectivity and dispersion for Lophelia pertusa may become highly limited between the Northern Gulf of Mexico and the Gulf Stream and Carolinian Atlantic. Areas of refugia identified in this study provide precise targets for protection against bottom trawling and offshore drilling. These results can complement real-world observations and help inform environmental management policy for this highly important deep-sea coral species.