Distribution and predicted climatic refugia for a reef‐building cold‐water coral on the southeast US margin

Abstract

Climate change is reorganizing the planet's biodiversity, necessitating proactive management of species and habitats based on spatiotemporal predictions of distributions across climate scenarios. In marine settings, climatic changes will predominantly manifest via warming, ocean acidification, deoxygenation, and changes in hydrodynamics. Lophelia pertusa, the main reef‐forming coral present throughout the deep Atlantic Ocean (>200 m), is particularly sensitive to such stressors with stark reductions in suitable habitat predicted to accrue by 2100 in a business‐as‐usual scenario. However, with new occurrence data for this species along with higher‐resolution bathymetry and climate data, it may be possible to locate further climatic refugia. Here, we synthesize new and published biogeographic, geomorphological, and climatic data to build ensemble, multi‐scale habitat suitability models for L. pertusa on the continental margin of the southeast United States (SEUS). We then project these models in two timepoints (2050, 2100) and four climate change scenarios to characterize the occurrence probability of this critical cold‐water coral (CWC) habitat now and in the future. Our models reveal the extent of reef habitat in the SEUS and corroborate it as the largest currently known essentially continuous CWC reef province on earth, and also predict abundance of L. pertusa to identify key areas, including those outside areas currently protected from bottom‐contact fishing. Drastic reductions in L. pertusa climatic suitability index emerged primarily after 2050 and were concentrated at the shallower end (<~550 m) of the regional distribution under the Gulf Stream main axis. Our results thus suggest a depth‐driven climate refuge effect where deeper, cooler reef sites experience lesser declines. The strength of this effect increases with climate scenario severity. Taken together, our study has implications for the regional and global management of this species, portending changes in the biodiversity reliant on CWC habitats and the critical ecosystem services they provide.

Mapping and Geomorphic Characterization of the Vast Cold-Water Coral Mounds of the Blake Plateau

“…Gulf Stream transport varies seasonally, with surface water transport peaking in the fall and reaching a minimum in the spring but deep-water transport showing the opposite seasonal peak fluctuations and with a larger magnitude [46]. The study area encompasses subregions of the Blake Plateau referred to by other researchers under a variety of names, including Stetson Reefs [10], Stetson Banks [35], Savannah Banks [47], Hoyt Hills, Richardson Hills, Richardson Reef [31], "Million Mounds," and portions of the Miami Terrace and Charleston Bump. The numbered black point features on the map correspond to the locations of some of the previous study locations described on the Blake Plateau: 1-Stetson Banks [10,11], 2-Savannah Banks [46], 3-Jacksonville Lithoherms [10], 4-St. Augustine [15], and 5-Cape Canaveral Pinnacles [15].…”

“…The region offshore of the southeastern U.S. contains the most extensive Desmophyllum pertusum (previously referenced in the literature as Lophelia pertusa) and Oculina CWC ecosystems documented within U.S. waters [11,[31][32][33][34][35]. Desmophyllum pertusum is the most common reef-building CWC documented in the North Atlantic and has been found in depths ranging from 39 to 3383 m [13,36], but it is most commonly found between about 200 about 1000 m. Studies in the Gulf of Mexico on artificial structures calculated minimum Desmophyllum pertusum growth rates of 3.2 to 32.3 mm/year [37].…”

Insights from the management of offshore energy resources: Toward an ecosystem-services based management approach for deep-ocean industries

“…These methods are frequently used for single-taxon prediction, which can be applied to indicator taxa for designated VMEs or, in the scenario presented here, ecosystem services. Predictive habitat models have now progressed to allow for ensemble modeling of entire community or habitat types (Mata et al, 2020;Uhlenkott et al, 2021) and for projecting their response to changing conditions (Morato et al, 2020;Gasbarro et al, 2022).…”

A Selected Review of Impacts of Ocean Deoxygenation on Fish and Fisheries

“…Loss of oxygen in marine ecosystems has been studied regionally and has significant impacts on their biodiversity and the ecosystem services they generate. Gasbarro et al (2022) predict that Lophelia pertusa, a deep Atlantic Ocean reef-forming coral, will experience significant reductions in climatic suitability due to the loss of oxygen, potentially impacting cold-water coral habitats in the south-east US margin [79]. The Baltic Sea has experienced bottom water deoxygenation due to anthropogenic pressure, leading to decreased water quality, loss of biodiversity, and reduced fish populations, impacting marine ecosystem services [80].…”