High resolution ecological niche modelling of the cold-water coral Lophelia pertusa in the Gulf of Mexico (original) (raw)
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Short-term environmental variability in cold-water coral habitat at Viosca Knoll, Gulf of Mexico
Deep-sea Research Part I-oceanographic Research Papers, 2010
The Lophelia pertusa community at Viosca Knoll (VK826) is the most extensive found to date in the Gulf of Mexico. As part of a multi-disciplinary study, the physical setting of this area was described using benthic landers, CTD transects and remotely operated vehicle observations. The site was broadly characterised into three main habitats: (1) dense coral cover that resembles biogenic reef complexes, (2) areas of sediment, and (3) authigenic carbonate blocks with sparse coral and chemosynthetic communities. The coral communities were dominated by L. pertusa but also contained numerous solitary coral species. Over areas that contained L. pertusa, the environmental conditions recorded were similar to those associated with communities in the north-eastern Atlantic, with temperature (8.5-10.6 1C) and salinity ( $ 35) falling within the known species niche for L. pertusa. However, dissolved oxygen concentrations (2.7-2.8 ml l À 1 ) and density (s Y , 27.1-27.2 kg m À 3 ) were lower and mass fluxes from sediment trap data appeared much higher (4002-4192 mg m À 2 d À 1 ). Yet, this species still appears to thrive in this region, suggesting that L. pertusa may not be as limited by lower dissolved oxygen concentrations as previously thought. The VK826 site experienced sustained eastward water flow of 10-30 cm s À 1 over the 5-day measurement period but was also subjected to significant shortterm variability in current velocity and direction. In addition, two processes were observed that caused variability in salinity and temperature; the first was consistent with internal waves that caused temperature variations of 0.8 1C over 5-11 h periods. The second was high-frequency variability (20-30 min periods) in temperature recorded only at the ALBEX site. A further pattern observed over the coral habitat was the presence of a 24 h diel vertical migration of zooplankton that may form part of a food chain that eventually reaches the corals. The majority of detailed studies concerning local environmental conditions in L. pertusa habitats have been conducted within the north-eastern Atlantic, limiting most knowledge of the niche of this species to a single part of an ocean basin. Data presented here show that the corals at VK826 are subjected to similar conditions in temperature, salinity, and flow velocity as their counterparts in the north-east Atlantic, although values for dissolved oxygen and density (sigma-theta: s Y ) are different. Our data also highlight novel observations of short-term environmental variability in cold-water coral habitat.
Open-File Report, 2017
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Open File Report, 2008
Define species composition, diversity, and numerical dominance of fishes and mobile megafaunal invertebrates on Gulf of Mexico Lophelia reefs and associated biotopes. 2. Define and compare mobile megafaunal, infaunal macrofaunal, and meiofaunal biotope affinities, population densities, biomass, diversity and population dispersion for the Lophelia reef biotope, other reef-associated biotopes, and comparative non-reef biotopes (e.g., the soft-substrate biotope of the surrounding open slope biome). Chapter 1. Introduction to the Investigations Randall et al. 1-2 3. Obtain tissue samples (target n = 30 samples per taxon and/or per ontogenetic stage of a taxon) for analysis of stable carbon, nitrogen, and sulfur isotopes. Samples were to be obtained from taxa forming the Lophelia community, as well as comparative taxa forming the overall oceanic food web, surface to substrate, including plankton and Sargassum carbon sources. 4. Obtain Lophelia and soft coral branch/stolon samples to determine ages via ring-count, isotope probe, and/or radiometric methodology. Also employ similar methods to age living coral, and potentially determine growth rate. Obtain reef and substrate rocks to determine origin and age of both Lophelia reefs, and of the underlying authigenic substrate. Obtain samples of reef sands and comparative off-reef soft substrate to analyze sediment origins. 5. Contrast megafaunal fish, and mobile invertebrate community structure for Gulf of Mexico versus Lophelia reefs known from other regions of the world ocean. 6. Using video and digital still images, document interaction of the Lophelia community fauna with the fish and invertebrate megafaunas continuously or facultatively utilizing deep coral and associated or comparative biotopes. Objectives undertaken specific to molecular biology and microbial investigators: 7. Document biodiversity of Lophelia and other scleractinian corals using informative nuclear and mitochondrial DNA markers and appropriate phylogenetic analyses. 8. Develop variable microsatellite DNA markers for Gulf of Mexico L. pertusa. 9. Use microsatellite markers to quantify local and regional patterns of genetic variation in Lophelia, including an assessment of genetic connectivity between reefs, relative contributions of clonal (asexual) and sexual reproduction, and inferred larval dispersal patterns. 10. Investigate the physiological state of Lophelia by determining the expression of genes related to basic life functions such as growth, differentiation, and reproduction. 11. Characterize the microbial community associated with L. pertusa and investigate whether the coral-associated microorganisms are acting as symbionts. 12. Determine if specialized sampling gear capable of preserving coral samples at depth and keeping live samples thermally insulated is necessary for microbial diversity and molecular biology studies. Chapter 1. Introduction to the Investigations Randall et al. 1-3 NOTE 1: This report addresses Objectives 1, 2, and 4-9, above. Objective 3 research, stable isotope analyses of trophic structure, is ongoing as of the date of this report, and will be published separately. NOTE 2: The program of USGS Lophelia community structure investigations on Viosca Knoll study sites reported on herein represents a companion program of study to that undertaken by Continental Shelf Associates (CSA) (S. Viada, Lead PI), Viosca Knoll to Green Canyon, on behalf of the MMS. The CSA program of Lophelia studies has produced a separate contractor report to MMS, OCS Study, MMS 2007-044 (CSA, 2007). BACKGROUND AND INTRODUCTION TO THE COMMUNITY STRUCTURE PROGRAM OF INVESTIGATIONS The objectives specified above were addressed over a series of three cruises, and subsequent laboratory analyses of specimens, video, images, and data. The three cruises were:
Limnology and Oceanography-methods, 2019
Mesoscale oceanic features such as eddies generate considerable environmental heterogeneity within the pelagic oceans, but their transient nature makes it difficult to identify both their spatial and temporal extent and their effects on the distribution of pelagic fauna. Simplifying these complex features using a biologically meaningful classification system will likely be a useful first step in understanding the extent of their influence in structuring open-ocean ecosystems. In this study, we present a tool to classify the pelagic environment in the Gulf of Mexico using sea-surface height and temperature-at-depth data from the 1/25 GOM HYbrid Coordinate Ocean Model (HYCOM). Three "water types" were identified: Loop Current-origin water (LCOW), Gulf common water (CW), and mixed (MIX) water, where the latter represents an intermediate state during the degradation of LCOW to CW. The HYCOM-derived classifications were validated against in situ CTD data and microbial samples collected through 2015-2016 by the Deep Pelagic Nekton Dynamics of the Gulf of Mexico (DEEPEND) consortium. The validation data comprised classifications derived from both temperature-depth (TD) and temperature-salinity (TS) profiles and from microbial community analyses from the surface to mesopelagic depths. The HYCOM classifications produced an overall agreement rate of 77% with the TS/TD classifications, and 79% with the microbial classifications. With applicability across a wide range of spatial and temporal scales, we believe that the system provides a useful, complementary tool for biological oceanographers and resource managers interested in better understanding the effects of major mesoscale features on the pelagic biota.
Environmental forcing of the Campeche cold-water coral province, southern Gulf of Mexico
With an extension of > 40 km 2 the recently discovered Campeche cold-water coral province located at the northeastern rim of the Campeche Bank in the southern Gulf of Mexico belongs to the largest coherent cold-water coral areas discovered so far. The Campeche province consists of numerous 20-40 m-high elongated coral mounds that are developed in intermediate water depths of 500 to 600 m. The mounds are colonized by a vivid cold-water coral ecosystem that covers the upper flanks and summits. The rich coral community is dominated by the framework-building Scleractinia Enallopsammia profunda and Lophelia pertusa, while the associated benthic megafauna shows a rather scarce occurrence. The recent environmental setting is characterized by a high surface water production caused by a local upwelling center and a dynamic bottom-water regime comprising vigorous bottom currents, obvious temporal variability, and strong density contrasts, which all together provide optimal conditions for the growth of cold-water corals. This setting -potentially supported by the diel vertical migration of zooplankton in the Campeche area -controls the delivering of food particles to the corals. The Campeche cold-water coral province is, thus, an excellent example highlighting the importance of the oceanographic setting in securing the food supply for the development of large and vivid cold-water coral ecosystems.
Caribbean Journal of Science, 2013
The deep-sea (200-1000 m) seafloor off the southeastern U.S. has a variety of extensive deep-sea coral ecosystem (DSCE) habitats including: deep-water coral mounds; various hard-bottom habitats off Florida including the Miami Terrace, Pourtalès Terrace, and deep-water canyons (Agassiz and Tortugas Valleys); and deep island slopes off western Bahamas and northern Cuba. The dominant structure-forming scleractinian corals are Lophelia pertusa and Enallopsammia profunda; other structure-forming taxa include stylasterid corals, gorgonians, black corals, and sponges. This biota is associated with hard-bottom seafloor of variable high-relief topography which can be remotely identified from bathymetric data. NOAA bathymetric contour maps and digital elevation models were used to identify and delineate the areal extent of potential DSCE habitat in the region from northeastern Florida through the Straits of Florida. These were ground-truthed with 241 dives with submersibles and remotely operated vehicles which confirmed deep-sea coral habitat. We estimate a total of 39,910 km 2 of DSCE habitat in this region. By comparison, the estimated areal extent of shallow-water coral habitat for all U.S. waters is 36,813 km 2 . Bottom trawling remains the greatest threat to DSCEs worldwide, and as a result NOAA has established five deep-water Coral Habitat Areas of Particular Concern (CHAPCs), encompassing 62,714 km 2 from North Carolina to south Florida, which will protect much of the known deep-sea coral habitat in this region. High-resolution surveys are not only critical to define DSCE habitats but also to define areas devoid of coral and sponge habitats that may allow for potential bottom fisheries and energy development. Reed 2008), and the percentage of seafloor explored visually with human occupied submersibles and remotely operated vehicles (ROVs) remains small. In the broad sense, DSCEs in this region occur at depths of 50 m to >1000 m and consist of structureforming, deep-water corals (including scleractinian corals, gorgonian octocorals, black corals, and stylasterid hydrozoan corals) and other associated structureforming species such as sponges, bryozoans, and hydroids, all of which may provide habitat to hundreds of species of invertebrates
Potential Connectivity of Coldwater Black Coral Communities in the Northern Gulf of Mexico
PLOS ONE, 2016
The black coral Leiopathes glaberrima is a foundation species of deep-sea benthic communities but little is known of the longevity of its larvae and the timing of spawning because it inhabits environments deeper than 50 m that are logistically challenging to observe. Here, the potential connectivity of L. glaberrima in the northern Gulf of Mexico was investigated using a genetic and a physical dispersal model. The genetic analysis focused on data collected at four sites distributed to the east and west of Mississippi Canyon, provided information integrated over many (~10,000) generations and revealed low but detectable realized connectivity. The physical dispersal model simulated the circulation in the northern Gulf at a 1km horizontal resolution with transport-tracking capabilities; virtual larvae were deployed 12 times over the course of 3 years and followed over intervals of 40 days. Connectivity between sites to the east and west of the canyon was hampered by the complex bathymetry, by differences in mean circulation to the east and west of the Mississippi Canyon, and by flow instabilities at scales of a few kilometers. Further, the interannual variability of the flow field surpassed seasonal changes. Together, these results suggest that a) dispersal among sites is limited, b) any recovery in the event of a large perturbation will depend on local larvae produced by surviving individuals, and c) a competency period longer than a month is required for the simulated potential connectivity to match the connectivity from multi-locus genetic data under the hypothesis that connectivity has not changed significantly over the past 10,000 generations.