Andrea M. Quattrini

Impact of the Deepwater Horizon oil spill on a deep-water coral community in the Gulf of Mexico

To assess the potential impact of the Deepwater Horizon oil spill on offshore ecosystems, 11 sites hosting deep-water coral communities were examined 3 to 4 mo after the well was capped. Healthy coral communities were observed at all sites >20 km from the Macondo well, including seven sites previously visited in September 2009, where the corals and communities appeared unchanged. However, at one site 11 km southwest of the Macondo well, coral colonies presented widespread signs of stress, including varying degrees of tissue loss, sclerite enlargement, excess mucous production, bleached commensal ophiuroids, and covering by brown flocculent material (floc). On the basis of these criteria the level of impact to individual colonies was ranked from 0 (least impact) to 4 (greatest impact). Of the 43 corals imaged at that site, 46% exhibited evidence of impact on more than half of the colony, whereas nearly a quarter of all of the corals showed impact to >90% of the colony. Additionally, 53% of these corals’ ophiuroid associates displayed abnormal color and/or attachment posture. Analysis of hopanoid petroleum biomarkers isolated from the floc provides strong evidence that this material contained oil from the Macondo well. The presence of recently damaged and deceased corals beneath the path of a previously documented plume emanating from the Macondo well provides compelling evidence that the oil impacted deep-water ecosystems. Our findings underscore the unprecedented nature of the spill in terms of its magnitude, release at depth, and impact to deep-water ecosystems.

Further Evidence for the Invasion and Establishment of Pterois volitans (Teleostei: Scorpaenidae) Along the Atlantic Coast of the United States

Abstract We document the continued population expansion of red lionfish, Pterois volitans, the first documented successful introduction of an invasive marine fish species from the western Pacific to Atlantic coastal waters of the United States. Red lionfish are indigenous to the Indo-Pacific and have apparently established one or more breeding populations on reefs off the southeastern United States. Fifty-nine specimens, most presumably adult red lionfish, were documented or collected on live-bottom reefs off North Carolina, South Carolina, and Florida, and on a manmade structure off Georgia. Observation/collection depths and bottom water temperatures for these fish ranged from 40–99 m and 13.8–24.4°C, respectively. Eleven juvenile lionfish, believed to be expatriated from southeastern waters, were collected in estuaries along the coast of Long Island, NY, at depths of 0–5 m and water temperatures ranging from 13.8–16.5 °C. Twelve of the total 70 specimens collected or observed were positively identified as red lionfish. Based on histological assessment of gonad tissue, two reproductively-active males and one immature female were collected. The life history of red lionfish, especially their reproductive biology and food habits, should be investigated along the east coast of the US to determine the potential impacts of this species on ecosystems they have invaded.

Niche divergence by deep-sea octocorals in the genus Callogorgia across the continental slope of the Gulf of Mexico.

Environmental variables that are correlated with depth have been suggested to be among the major forces underlying speciation in the deep sea. This study incorporated phylogenetics and ecological niche models (ENM) to examine whether congeneric species of Callogorgia (Octocorallia: Primnoidae) occupy different ecological niches across the continental slope of the Gulf of Mexico (GoM) and whether this niche divergence could be important in the evolution of these closely related species. Callogorgia americana americana, Callogorgia americana delta and Callogorgia gracilis were documented at 13 sites in the GoM (250–1000 m) from specimen collections and extensive video observations. On a first order, these species were separated by depth, with C. gracilis occurring at the shallowest sites, C. a. americana at mid‐depths and C. a. delta at the deepest sites. Callogorgia a. delta was associated with areas of increased seep activity, whereas C. gracilis and C. a. americana were associated with narrow, yet warmer, temperature ranges and did not occur near cold seeps. ENM background and identity tests revealed little to no overlap in ecological niches between species. Temporal calibration of the phylogeny revealed the formation of the Isthmus of Panama was a vicariance event that may explain some of the patterns of speciation within this genus. These results elucidate the potential mechanisms for speciation in the deep sea, emphasizing both bathymetric speciation and vicariance events in the evolution of a genus across multiple regions.

Testing the depth-differentiation hypothesis in a deepwater octocoral

The depth-differentiation hypothesis proposes that the bathyal region is a source of genetic diversity and an area where there is a high rate of species formation. Genetic differentiation should thus occur over relatively small vertical distances, particularly along the upper continental slope (200–1000 m) where oceanography varies greatly over small differences in depth. To test whether genetic differentiation within deepwater octocorals is greater over vertical rather than geographical distances, Callogorgia delta was targeted. This species commonly occurs throughout the northern Gulf of Mexico at depths ranging from 400 to 900 m. We found significant genetic differentiation (FST = 0.042) across seven sites spanning 400 km of distance and 400 m of depth. A pattern of isolation by depth emerged, but geographical distance between sites may further limit gene flow. Water mass boundaries may serve to isolate populations across depth; however, adaptive divergence with depth is also a possible scenario. Microsatellite markers also revealed significant genetic differentiation (FST = 0.434) between C. delta and a closely related species, Callogorgia americana, demonstrating the utility of microsatellites in species delimitation of octocorals. Results provided support for the depth-differentiation hypothesis, strengthening the notion that factors covarying with depth serve as isolation mechanisms in deep-sea populations.

Exploration of the Canyon-Incised Continental Margin of the Northeastern United States Reveals Dynamic Habitats and Diverse Communities

The continental margin off the northeastern United States (NEUS) contains numerous, topographically complex features that increase habitat heterogeneity across the region. However, the majority of these rugged features have never been surveyed, particularly using direct observations. During summer 2013, 31 Remotely-Operated Vehicle (ROV) dives were conducted from 494 to 3271 m depth across a variety of seafloor features to document communities and to infer geological processes that produced such features. The ROV surveyed six broad-scale habitat features, consisting of shelf-breaching canyons, slope-sourced canyons, inter-canyon areas, open-slope/landslide-scar areas, hydrocarbon seeps, and Mytilus Seamount. Four previously unknown chemosynthetic communities dominated by Bathymodiolus mussels were documented. Seafloor methane hydrate was observed at two seep sites. Multivariate analyses indicated that depth and broad-scale habitat significantly influenced megafaunal coral (58 taxa), demersal fish (69 taxa), and decapod crustacean (34 taxa) assemblages. Species richness of fishes and crustaceans significantly declined with depth, while there was no relationship between coral richness and depth. Turnover in assemblage structure occurred on the middle to lower slope at the approximate boundaries of water masses found previously in the region. Coral species richness was also an important variable explaining variation in fish and crustacean assemblages. Coral diversity may serve as an indicator of habitat suitability and variation in available niche diversity for these taxonomic groups. Our surveys added 24 putative coral species and three fishes to the known regional fauna, including the black coral Telopathes magna, the octocoral Metallogorgia melanotrichos and the fishes Gaidropsarus argentatus, Guttigadus latifrons, and Lepidion guentheri. Marine litter was observed on 81% of the dives, with at least 12 coral colonies entangled in debris. While initial exploration revealed the NEUS region to be both geologically dynamic and biologically diverse, further research into the abiotic conditions and the biotic interactions that influence species abundance and distribution is needed.

A New Species of Hagfish (Myxinidae: Eptatretus) Associated with Deep-Sea Coral Habitat in the Western North Atlantic

Abstract Eptatretus lopheliae, new species, is described from three specimens caught at 430–442 m depth in cold-water coral habitat off the southeastern United States. It is diagnosed by elongated tubular nostril, lack of nasal-sinus papillae, five pairs of gill pouches, 3-cusp multicusps in anterior and posterior row of teeth but with variation of 4 cusps in posterior row, 38–41 total cusp count, 19–21 prebranchial slime pores, 88–89 total pores, palatine tooth triangular, and pinkish-orange body color. Eptatretus lopheliae is a small hagfish species observed, videotaped, and caught in close association with Lophelia pertusa reef habitat.

Reply to Boehm and Carragher: Multiple lines of evidence link deep-water coral damage to Deepwater Horizon oil spill

Our original study (1) used visual inspection as well as biological and geochemical analyses of corals and the surrounding sediment to provide complementary and compelling evidence linking the Deepwater Horizon (DWH) oil spill to the presence of damaged deep-water corals and brittle stars 11 km from the site of the leaking oil.

Aspects of the Reproductive Biology of the Skate Fenestraja plutonia (Garman) off North Carolina

Abstract Fenestraja plutonia is an abundant member of the slope community in the western North Atlantic, occurring at depths of 293-1042 m. Aspects of the reproductive biology of F. plutonia were examined for specimens collected off North Carolina, in the summer-fall of 2001, 2002, and 2006. Male-to-female sex ratios were not significantly different from 1:1. The smallest mature male was 215 mm TL, and the smallest mature female was 230 mm TL. Length at 50% maturity was estimated at 231 mm TL for females and 233 mm TL for males, 89 and 90% of maximum TL, respectively. Deposited egg cases (n = 107; six containing embryos), three egg-bearing females, and 11 newly hatched juveniles were collected. It appears that the upper slope off Cape Lookout, NC, at the northern end of the species range, constitutes both an egg-laying area and possibly a nursery area for this species.

The utility of museum records for documenting distributions of deep-sea corals off the southeastern United States

Abstract Museum records can enhance distribution maps of deep-sea corals (DSC), but museum data usually acquired from online internet catalogues may be of uncertain quality. Also, many museum records are unavailable through online sources. Holdings of four structure-forming DSC species (Lophelia pertusa, Madrepora oculata, Enallopsammia profunda, Enallopsammia rostrata) collected from off the southeastern US were evaluated from the US National Museum of Natural History (NMNH), Harvard Universitys Museum of Comparative Zoology (MCZ), University of Miamis Marine Invertebrate Museum, and Yale Universitys Peabody Museum of Natural History. Data were gathered from online sources, selected publications, and personal visits to the MCZ and NMNH. Each record was located, if possible, specimens were photographed and additional data obtained, including whether the specimen was collected alive or dead. The resulting database was imported into ArcGIS to examine coral distributions. Museums yielded 304 records: 126 L. pertusa, 62 M. oculata, 113 E. profunda, 3 E. rostrata. Most (87%) records occurred between 400 and 900 m depths; some were <300 m (46–248 m) and >900 m (965–2195 m). Museum records confirmed geographic and bathymetric ranges of these corals and suggested areas for further exploration. Problems encountered in the museum data were varied but generally minor. Museum collections are useful for investigating DSC distributions; however, these data require more scrutiny than they usually receive. Visits to museums and/or interaction with museum staff are recommended to improve museum data utility.

Assessment of Canyon Wall Failure Process from Multibeam Bathymetry and Remotely Operated Vehicle (ROV) Observations, U.S. Atlantic Continental Margin

Over the last few years, canyons along the northern U.S. Atlantic continental margin have been the focus of intensive research examining canyon evolution, submarine geohazards, benthic ecology and deep-sea coral habitat. New high-resolution multibeam bathymetry and Remotely Operated Vehicle (ROV) dives in the major shelf-breaching and minor slope canyons, provided the opportunity to investigate the size of, and processes responsible for, canyon wall failures. The canyons cut through thick Late Cretaceous to Recent mixed siliciclastic and carbonate-rich lithologies which impart a primary control on the style of failures observed. Broad-scale canyon morphology across much of the margin can be correlated to the exposed lithology. Near vertical walls, sedimented benches, talus slopes, and canyon floor debris aprons were present in most canyons. The extent of these features depends on canyon wall cohesion and level of internal fracturing, and resistance to biological and chemical erosion. Evidence of brittle failure over different spatial and temporal scales, physical abrasion by downslope moving flows, and bioerosion, in the form of burrows and surficial scrape marks provide insight into the modification processes active in these canyons. The presence of sessile fauna, including long-lived, slow growing corals and sponges, on canyon walls, especially those affected by failure provide a critical, but as yet, poorly understood chronological record of geologic processes within these systems.