Black Corals of the Flower Garden Banks National Marine Sanctuary

Black corals (Cnidaria: Anthozoa: Antipatharia) of the Flower Garden Banks National Marine Sanctuary (FGBNMS) are described. A key to the species is provided and supplemented with in situ and laboratory photos. The microscopic skeletal features of the species are illustrated from photographs taken with a scanning electron microscope. Thirteen species of black corals are found in the FGBNMS, belonging to the families Antipathidae (Antipathes furcata Gray 1857; Antipathes atlantica Gray 1857, Stichopathes luetkeni Brook 1889; Stichopathes pourtalesi Brook 1889, and Stichopathes sp.); Aphanipathidae [Aphanipathes pedata (Gray 1857), Elatopathes abietina (Pourtalès 1874), Acanthopathes thyoides (Pourtalès 1880) and Phanopathes expansa (Opresko and Cairns 1992)]; and Myriopathidae [Plumapathes pennacea (Pallas 1766), Tanacetipathes tanacetum (Pourtalès 1880), Tanacetipathes hirta (Gray 1857), and Tanacetipathes cf. thamnea (Warner 1981)]

Validation of Image-Based Species Identifications of Black Corals (Order Antipatharia) on Mesophotic Rocks

Biodiversity, an important measure of ecosystem health, is challenging to ascertain using sampled specimens in remote deep-sea environments. As image-based identifications become a predominant method for deep-sea species characterizations, there is a need to evaluate the accuracy of species- and genus-level identifications from video and still images to provide a reliable measure of biodiversity. This study presents a validation of the ability to make accurate image-based identifications of black coral species in the northwestern Gulf of Mexico from standard-definition video collected by a remotely operated vehicle. Results indicate that the greatest number of misidentifications occurred at species-level groupings (42.2% error), whereas genus-level groupings possessed 12.0% error, and identifications to kappa groupings had no error. We recommend genus-level groupings to maintain accurate identifications while maximizing estimates of biodiversity

Patterns of Mesophotic Benthic Community Structure on Banks Off vs Inside the Continental Shelf Edge, Gulf of Mexico

Information on the biodiversity and geographic patterns of mesophotic, sessile, epibenthic communities on banks around and at the edge of the continental shelf, northern Gulf of Mexico, has been limited. These communities vary in their environments and are prone to disturbance from Outer Continental Shelf oil- and gas-related activities and fishing (trawling and long-lining). We surveyed these communities on the flanks of 13 banks to determine species richness, species composition, similarities between benthic communities, and geographic patterns in community structure. We sampled to ≤ 181 m in depth via a remotely operated vehicle using a vertically mounted digital camera bearing two lasers for scale and a flash (generally 10 drop-sites/bank, 5 transects/drop-site, and ≤11 photos/transect). Data analysis via PATN revealed three main Bank Groups: the on-shelf group containing 29 Fathom and Sonnier Banks; an anomalous bank—Geyer Bank; and the shelf edge group—Horseshoe, 28 Fathom, Bright, Alderdice, Bouma, Rankin, Rezak, Elvers, McGrail, and Sidner Banks. Most species-rich banks (Bank Group 3) occurred at the shelf edge. Two of the species-poor banks (Bank Group 1) occurred further north, inside the shelf. Geyer Bank (Bank Group 2) occurred at the shelf edge but was anomalously species-poor. Box-and-whisker analyses identified four Species Groups driving the Bank Groupings. Species Group 4 (the Elatopathes abientina/Nicella sp. group) was the largest (also containing Peysonellia sp.), primarily defining Bank Group 3. Species Groups 2 (the Antipathes sp./Gorgonian G04 group) and 3 (low species abundances) were also associated with Bank Group 3. Species Group 4 (the Elatopathes abientina/Nicella sp. group) was a major contributor to Bank Group 2 (Geyer Bank). Species Group 2 (the Antipathes sp./Gorgonian G04 group) was the primary constituent of the on-shelf Bank Group 1, also characterized by low species richness. Most species had a comparative abundance of ≤20%. The high species richness and affinities exhibited by Bank Group 3 are likely due to continual exposure to warm, low-turbidity Caribbean water at the shelf edge. Banks inside the shelf likely vary from the others as a result of exposure to cooler winter temperatures and higher turbidity due to wind-forced inshore currents. The reasons for the unique community structure on Geyer Bank are as yet unknown. Shelf-edge banks tend to be more species rich than on-shelf banks

Antipatharian Diversity and Habitat Suitability Mapping in the Mesophotic Zone of the Northwestern Gulf of Mexico

Little is known about the distribution of black corals in the northwestern Gulf of Mexico. Of thirty-nine species of black coral documented in the Western Atlantic, thirty have been previously documented by various studies in the Gulf of Mexico. This study proposes potential range extensions for four black coral species, including Stichopathes gracilis, Stichopathes semiglabra, Tanacetipathes paula, and Tanacetipathes spinescens, to include the Gulf of Mexico. The validation of in situ identifications of black coral species is evaluated, and recommendations for species identifications and species groupings are made. Black coral associated fauna are documented, supporting known associations and documenting potentially new associations and species. Habitat suitability models for the distribution of black coral species at selected banks in the northwestern Gulf of Mexico were generated. Presence-only models made using the MaxEnt modeling program were compared to presence-absence models made using Boosted Regression Tree modeling techniques. Presence-absence models were documented to have greater predictive accuracy than the presence-only models, which showed evidence of model overfitting. The model was projected to five similar salt-dome features in the region, highlighting extensive habitat for multiple black coral species in these unexplored habitats. This study presents habitat suitability maps as a testable hypothesis for black coral distribution in the mesophotic zone of this region

Patterns of Mesophotic Benthic Community Structure on Banks Off vs Inside the Continental Shelf Edge, Gulf of Mexico

Information on the biodiversity and geographic patterns of mesophotic, sessile, epibenthic communities on banks around and at the edge of the continental shelf, northern Gulf of Mexico, has been limited. These communities vary in their environments and are prone to disturbance from Outer Continental Shelf oil- and gas-related activities and fishing (trawling and long-lining). We surveyed these communities on the flanks of 13 banks to determine species richness, species composition, similarities between benthic communities, and geographic patterns in community structure. We sampled to ≤ 181 m in depth via a remotely operated vehicle using a vertically mounted digital camera bearing two lasers for scale and a flash (generally 10 drop-sites/bank, 5 transects/drop-site, and ≤11 photos/transect). Data analysis via PATN revealed three main Bank Groups: the on-shelf group containing 29 Fathom and Sonnier Banks; an anomalous bank—Geyer Bank; and the shelf edge group—Horseshoe, 28 Fathom, Bright, Alderdice, Bouma, Rankin, Rezak, Elvers, McGrail, and Sidner Banks. Most species-rich banks (Bank Group 3) occurred at the shelf edge. Two of the species-poor banks (Bank Group 1) occurred further north, inside the shelf. Geyer Bank (Bank Group 2) occurred at the shelf edge but was anomalously species-poor. Box-and-whisker analyses identified four Species Groups driving the Bank Groupings. Species Group 4 (the Elatopathes abientina/Nicella sp. group) was the largest (also containing Peysonellia sp.), primarily defining Bank Group 3. Species Groups 2 (the Antipathes sp./Gorgonian G04 group) and 3 (low species abundances) were also associated with Bank Group 3. Species Group 4 (the Elatopathes abientina/Nicella sp. group) was a major contributor to Bank Group 2 (Geyer Bank). Species Group 2 (the Antipathes sp./Gorgonian G04 group) was the primary constituent of the on-shelf Bank Group 1, also characterized by low species richness. Most species had a comparative abundance of ≤20%. The high species richness and affinities exhibited by Bank Group 3 are likely due to continual exposure to warm, low-turbidity Caribbean water at the shelf edge. Banks inside the shelf likely vary from the others as a result of exposure to cooler winter temperatures and higher turbidity due to wind-forced inshore currents. The reasons for the unique community structure on Geyer Bank are as yet unknown. Shelf-edge banks tend to be more species rich than on-shelf banks

Stetson Bank long-term monitoring: 2020 and 2021 annual report

This document contains descriptions of the methods used, analyses of field data collected, summaries of field notes, details of challenges faced, and significant observations made during 2020–2021 annual long-term monitoring of fish and benthic communities at Stetson Bank. Stetson Bank is an uplifted claystone/siltstone feature located 130 km southeast of Galveston, Texas within Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico. It supports a productive benthic community of sponges and coral. Annual monitoring of the bank crest has been conducted since 1993. Surveys of the mesophotic zone surrounding the bank crest began in 2015. Field work and data collection were limited in 2020 and 2021 due to vessel, diving, and operational restrictions established in response to the COVID-19 pandemic. In 2020, a single quarterly water sampling cruise was completed, followed by a cruise for water quality instrument exchange. In 2021, two water sampling cruises were completed, and instruments that recorded temperature, salinity, and turbidity data since 2019 were exchanged. A subset of bank crest repetitive photostations (n = 24), representing 40% of all photostations on the Stetson Bank crest, were captured in 2021. In 2021, mean percent cover was 6.56% for coral, 7.09% for sponges, and 42.72% for macroalgae. Bleaching and/or paling was observed in Millepora alcicornis colonies in 2021; however, no signs of stony coral tissue loss disease were observed. Seawater temperatures on the bank exceeded 30 oC for one day in 2020 and for 18 nonconsecutive days in 2021. This report highlights the importance of long-term monitoring efforts by providing a summary of benthic and water quality trends on the bank crest and detailing challenges and resolutions for future field work.This study was funded by the U.S. Department of the Interior, BSEE through Interagency Agreement E21PG00009 with NOAA’s National Ocean Service, ONMS, through FGBNMS. Field work in 2020 and 2021 was carried out under permit FGBNMS-2019-001

Long-Term Monitoring at East and West Flower Garden Banks National Marine Sanctuary, 2011-2012, Volume 1: Technical Report

This is a study on the 25 years of continuous monitoring of coral reefs in the East and West Flower Garden Banks in the Gulf of Mexico. The study was based on concerns of the impact of offshore oil and gas impact on these sensitive reefs

Long-Term Monitoring at the East and West Flower Garden Banks National Marine Sanctuary, 2009-2010, Volume 1: Technical Report

This is the 20 year analyses report on the coral reefs of the Flower Garden Banks National Marine Sanctuary

Volume 2: Appendices

A report of a long-term monitoring at a national marine sanctuary

Seasonal variability of carbonate chemistry and decadal changes in waters of a marine sanctuary in the Northwestern Gulf of Mexico

We report seasonal water column carbonate chemistry data collected over a three-year period (late 2013 to 2016) at Flower Garden Banks National Marine Sanctuary (FGBNMS) located on the subtropical shelf edge of the northwestern Gulf of Mexico. The FGBNMS hosts the northernmost tropical coral species in the contiguous United States, with over 50% living coral cover. Presented here are results from samples of the upper 25 m of the water column collected from September 2013 to November 2016. Additionally, following a localized mortality event likely associated with major continental flooding in summer 2016, water samples from up to similar to 250 m depth were collected in the broader FGBNMS area on a rapid response cruise to examine the seawater carbonate system. Both surface (< 5 m) total alkalinity (TA) and total dissolved inorganic carbon (DIC) vary over small ranges (2391 +/- 19 mu mol kg(-1) and 2060 +/- 19 mu mol kg(-1), respectively) for all times-series samples. Temperature and salinity both played an important role in controlling the surface water carbonate system dynamics, although temperature was the sole significant factor when there was no flooding. The FGBNMS area acted as a sink for atmospheric CO2 in winter and a CO2 source in summer, while the time-integrated CO2 flux is close to zero (- 0.14 +/- 1.96 mmol-C m(-2) yr(-1)). Results from three cruises, i.e., the Gulf of Mexico and East Coast Carbon Project (GOMECC-1) in 2007, the rapid response study, and the Gulf of Mexico Ecosystems and Carbon Cruise (GOMECC-3), revealed decreases in both pH and saturation state with respect to aragonite (Omega(arag)) in subsurface waters (similar to 100-250 m) over time. These decreases are larger than those observed in other tropical and subtropical waters. Based on reaction stoichiometry, calculated anthropogenic CO2 contributed 30-41% of the overall DIC increase, while elevated respiration accounted for the rest