Distribution of deep-water scleractinian and stylasterid corals across abiotic environmental gradients on three seamounts in the Anegada Passage

© Copyright 2020 Auscavitch et al. In the Caribbean Basin the distribution and diversity patterns of deep-sea scleractinian corals and stylasterid hydrocorals are poorly known compared to their shallow-water relatives. In this study, we examined species distribution and community assembly patterns of scleractinian and stylasterid corals on three high-profile seamounts within the Anegada Passage, a deep-water throughway linking the Caribbean Sea and western North Atlantic. Using remotely operated vehicle surveys conducted on the E/V Nautilus by the ROV Hercules in 2014, we characterized coral assemblages and seawater environmental variables between 162 and 2,157 m on Dog Seamount, Conrad Seamount, and Noroît Seamount. In all, 13 morphospecies of scleractinian and stylasterid corals were identified from video with stylasterids being numerically more abundant than both colonial and solitary scleractinians. Cosmopolitan framework-forming species including Madrepora oculata and Solenosmilia variabilis were present but occurred in patchy distributions among the three seamounts. Framework-forming species occurred at or above the depth of the aragonite saturation horizon with stylasterid hydrocorals being the only coral taxon observed below Oarag values of 1. Coral assemblage variation was found to be strongly associated with depth and aragonite saturation state, while other environmental variables exerted less influence. This study enhances our understanding of the factors that regulate scleractinian and stylasterid coral distribution in an underreported marginal sea and establishes a baseline for monitoring future environmental changes due to ocean acidification and deoxygenation in the tropical western Atlantic

Perspectives on Research, Technology, Policy, and Human Resources for Improved Management of Ultra-Deep Oil and Gas Resources and Responses to Oil Spills

This chapter considers a series of research, technology, policy, and human resource-relevant recommendations aimed at identifying ultra-deep wellsite locations that may be problematic for risk of an oil spill, as well as enhancing prevention, preparedness, response, and subsequent injury assessment associated with ultra-deep oil spills. While various groups have offered research and process improvement recommendations, numbering in the high hundreds, this chapter focuses on 20 key research gaps and 4 policy changes that would improve outcomes for ultra-deep oil spill prevention and response. Recommended policy changes include (1) inclusion of site-specific risk assessments as an element of lease sale identification and approval, (2) collection of environmental baselines (both broadscale and installation-specific) and ongoing monitoring of oil contaminants, (3) improved transparency and data sharing for oil facility management and accidental releases, and (4) more formal international engagement in siting, oil spill preparedness, response, and impact assessment

Predation on parasitic gnathiid isopods on coral reefs: a comparison of Caribbean cleaning gobies with non-cleaning microcarnivores

On coral reefs, gnathiid isopods are a common blood-feeding ectoparasite of reef fishes that can have significant impacts on reef-fish health and fitness. Cleaner fishes and shrimps are the only major documented predators of gnathiids, removing them from the bodies of host fishes. However, gnathiids spend most of their lifecycle free living and thus may be eaten by other microcarnivorous fishes that collectively could have larger impacts on gnathiid populations. This study examined gut contents from Caribbean nocturnal reef microcarnivorous fish and from the Caribbean cleaning goby Elacatinus evelynae for the presence of gnathiid isopods. Among nocturnal microcarnivores, gnathiids were found in only a small proportion of the gut contents of grunts (5%) and cardinalfish (4%), but in a higher proportion of the gut contents of squirrelfish and soldierfish (26%). In comparison, most cleaning gobies collected in the morning had gnathiids (93%), with an average of 6.3 gnathiids per fish. While microcarnivorous fishes ate far fewer gnathiids, they were present in much greater numbers than cleaning gobies. These results support previous studies on cleaning gobies suggesting that individually, they consume high numbers of gnathiids. However, they also suggest that collectively, other predators could have an equal or greater impact on gnathiid populations