@article {Ross2017,
	title = {{Deep-sea coral and hardbottom habitats on the west Florida slope, eastern Gulf of Mexico}},
	journal = {Deep Sea Research Part I: Oceanographic Research Papers},
	volume = {120},
	year = {2017},
	pages = {14{\textendash}28},
	abstract = {Until recently, benthic habitats dominated by deep-sea corals (DSC) appeared to be less extensive on the slope of the Gulf of Mexico (GOM) than in the northeast Atlantic Ocean or off the southeastern US. There are relatively few bioherms (i.e., coral-built mounds) in the northern GOM, and most DSCs are attached to existing hard substrata (e.g., authigenically formed carbonate). The primary structure-forming, DSC in the GOM is Lophelia pertusa, but structure is also provided by other living and dead scleractinians, antipatharians (black corals), octocorals (gorgonians, soft corals), hydrocorals and sponges, as well as abundant rocky substrata. The best development of DSCs in the GOM was previously documented within Viosca Knoll oil and gas lease blocks 826 and 862/906 (north-central GOM) and on the Campeche Bank (southern GOM in Mexican waters). This paper documents extensive deep reef ecosystems composed of DSC and rocky hard-bottom recently surveyed on the West Florida Slope (WFS, eastern GOM) during six research cruises (2008{\textendash}2012). Using multibeam sonar, CTD casts, and video from underwater vehicles, we describe the physical and oceanographic characteristics of these deep reefs and provide size or area estimates of deep coral and hardground habitats. The multibeam sonar analyses revealed hundreds of mounds and ridges, some of which were subsequently surveyed using underwater vehicles. Mounds and ridges in {\textless}525 m depths were usually capped with living coral colonies, dominated by L. pertusa. An extensive rocky scarp, running roughly north-south for at least 229 km, supported lower abundances of scleractinian corals than the mounds and ridges, despite an abundance of settlement substrata. Areal comparisons suggested that the WFS may exceed other parts of the GOM slope in extent of living deep coral coverage and other deep-reef habitat (dead coral and rock). The complex WFS region warrants additional studies to better understand the influences of oceanography and geology on the occurrence of DSC and associated organisms. Protection measures are being considered to ensure the long-term integrity of this diverse ecosystem.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.dsr.2016.12.005},
	author = {Ross, S W and Rhode, M and Brooke, S}
}
@article {Bourque2017,
	title = {{Macrofaunal communities associated with chemosynthetic habitats from the U.S. Atlantic margin: A comparison among depth and habitat types}},
	journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
	volume = {137},
	year = {2017},
	pages = {42{\textendash}55},
	abstract = {Hydrocarbon seeps support distinct benthic communities capable of tolerating extreme environmental conditions and utilizing reduced chemical compounds for nutrition. In recent years, several locations of methane seepage have been mapped along the U.S. Atlantic continental slope. In 2012 and 2013, two newly discovered seeps were investigated in this region: a shallow site near Baltimore Canyon (BCS, 366{\textendash}412 m) and a deep site near Norfolk Canyon (NCS, 1467{\textendash}1602 m), with both sites containing extensive chemosynthetic mussel bed and microbial mat habitats. Sediment push cores, suction samples, and Ekman box cores were collected to quantify the abundance, diversity, and community structure of benthic macrofauna ({\textgreater}300 $μ$m) in mussel beds, mats, and slope habitats at both sites. Community data from the deep site were also assessed in relation to the associated sediment environment (organic carbon and nitrogen, stable carbon and nitrogen isotopes, grain size, and depth). Infaunal assemblages and densities differed both between depths and among habitat types. Macrofaunal densities in microbial mats were four times greater than those present in mussel beds and slope sediments and were dominated by the annelid families Dorvilleidae, Capitellidae, and Tubificidae, while mussel habitats had higher proportions of crustaceans. Diversity was lower in BCS microbial mat habitats, but higher in mussel and slope sediments compared to NCS habitats. Multivariate statistical analysis revealed specific sediment properties as important for distinguishing the macrofaunal communities, including larger grain sizes present within NCS microbial mat habitats and depleted stable carbon isotopes ($δ$13C) in sediments present at mussel beds. These results suggest that habitat differences in the quality and source of organic matter are driving the observed patterns in the infaunal assemblages, including high $\beta$ diversity and high variability in the macrofaunal community composition. This study is the first investigation of seep infauna along the U.S. Atlantic slope north of the Blake Ridge Diapir and provides a baseline for future regional comparisons to other seep habitats along the Atlantic margin.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.dsr2.2016.04.012},
	author = {Bourque, J R and Robertson, C M and Brooke, S and Demopoulos, A W J}
}
@article {Prouty2016,
	title = {{Insights into methane dynamics from analysis of authigenic carbonates and chemosynthetic mussels at newly-discovered Atlantic Margin seeps}},
	journal = {Earth and Planetary Science Letters},
	volume = {449},
	year = {2016},
	pages = {332{\textendash}344},
	abstract = {The recent discovery of active methane venting along the US northern and mid-Atlantic margin represents a new source of global methane not previously accounted for in carbon budgets from this region. However, uncertainty remains as to the origin and history of methane seepage along this tectonically inactive passive margin. Here we present the first isotopic analyses of authigenic carbonates and methanotrophic deep-sea mussels, Bathymodiolus sp., and the first direct constraints on the timing of past methane emission, based on samples collected at the upper slope Baltimore Canyon (\~{}385 m water depth) and deepwater Norfolk (\~{}1600 m) seep fields within the area of newly-discovered venting. The authigenic carbonates at both sites were dominated by aragonite, with an average View the MathML source$δ$C13 signature of -47{\textperthousand}-47{\textperthousand}, a value consistent with microbially driven anaerobic oxidation of methane-rich fluids occurring at or near the sediment{\textendash}water interface. Authigenic carbonate U and Sr isotope data further support the inference of carbonate precipitation from seawater-derived fluids rather than from formation fluids from deep aquifers. Carbonate stable and radiocarbon (View the MathML source$δ$C13 and View the MathML source$Δ$C13) isotope values from living Bathymodiolus sp. specimens are lighter than those of seawater dissolved inorganic carbon, highlighting the influence of fossil carbon from methane on carbonate precipitation. U{\textendash}Th dates on authigenic carbonates suggest seepage at Baltimore Canyon between 14.7{\textpm}0.6 ka14.7{\textpm}0.6 ka to 15.7{\textpm}1.6 ka15.7{\textpm}1.6 ka, and at the Norfolk seep field between 1.0{\textpm}0.7 ka1.0{\textpm}0.7 ka to 3.3{\textpm}1.3 ka3.3{\textpm}1.3 ka, providing constraint on the longevity of methane efflux at these sites. The age of the brecciated authigenic carbonates and the occurrence of pockmarks at the Baltimore Canyon upper slope could suggest a link between sediment delivery during Pleistocene sea-level lowstand, accumulation of pore fluid overpressure from sediment compaction, and release of overpressure through subsequent venting. Calculations show that the Baltimore Canyon site probably has not been within the gas hydrate stability zone (GHSZ) in the past 20 ka, meaning that in-situ release of methane from dissociating gas hydrate cannot be sustaining the seep. We cannot rule out updip migration of methane from dissociation of gas hydrate that occurs farther down the slope as a source of the venting at Baltimore Canyon, but consider that the history of rapid sediment accumulation and overpressure may play a more important role in methane emissions at this site.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.epsl.2016.05.023},
	author = {Prouty, N G and Sahy, D and Ruppel, C D and Roark, E B and Condon, D and Brooke, S and Ross, S W and Demopoulos, A W J}
}
@article {Brooke2014,
	title = {{First observations of the cold-water coral Lophelia pertusa in mid-Atlantic canyons of the USA}},
	journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
	volume = {104},
	year = {2014},
	pages = {245{\textendash}251},
	abstract = {The structure-forming, cold-water coral Lophelia pertusa is widely distributed throughout the North Atlantic Ocean and also occurs in the South Atlantic, North Pacific and Indian oceans. This species has formed extensive reefs, chiefly in deep water, along the continental margins of Europe and the United States, particularly off the southeastern U.S. coastline and in the Gulf of Mexico. There were, however, no records of L. pertusa between the continental slope off Cape Lookout, North Carolina (NC) (\~{}34{\textdegree}N, 76{\textdegree}W), and the rocky Lydonia and Oceanographer canyons off Cape Cod, Massachusetts (MA) (\~{}40{\textdegree}N, 68{\textdegree}W). During a research cruise in September 2012, L. pertusa colonies were observed on steep walls in both Baltimore and Norfolk canyons. These colonies were all approximately 2 m or less in diameter, usually hemispherical in shape and consisted entirely of live polyps. The colonies were found between 381 m and 434 m with environmental observations of: temperature 6.4{\textendash}8.6 {\textdegree}C; salinity 35.0{\textendash}35.6; and dissolved oxygen 2.06{\textendash}4.41 ml L-1, all of which fall within the range of known L. pertusa distributions. All colonies were observed on vertical walls or underneath overhangs in areas of high current, which differs from observations further south, where L. pertusa colonizes rocky ledges and outcroppings, often forming large bioherms. We discuss observations from Baltimore and Norfolk canyons in the context of the known distribution of this species in the North Atlantic.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {0967-0645},
	doi = {10.1016/j.dsr2.2013.06.011},
	url = {http://www.sciencedirect.com/science/article/pii/S0967064513002415},
	author = {Brooke, S and Ross, S W}
}
