TY - JOUR
T1 - Coral mortality event in the Flower Garden Banks of the Gulf of Mexico in July 2016
T2 - Local hypoxia due to cross-shelf transport of coastal flood waters?
AU - Le Hénaff, Matthieu
AU - Muller-Karger, Frank E.
AU - Kourafalou, Vassiliki H.
AU - Otis, Daniel
AU - Johnson, Kimberley A.
AU - McEachron, Lucas
AU - Kang, Hee Sook
N1 - Funding Information:
This paper is a result of research funded by the National Oceanic and Atmospheric Administration RESTORE Act Science Program under award NA15NOS4510226 to the University of Miami . It is a contribution to the Marine Biodiversity Observation Network (MBON) program. The work was partially supported by NASA grant NNX14AP62A ‘National Marine Sanctuaries as Sentinel Sites for a Demonstration Marine Biodiversity Observation Network (MBON)’ funded under the National Ocean Partnership Program ( NOPP RFP NOAA-NOS-IOOS-2014-2003803 in partnership between NOAA , BOEM , and NASA ), and the NOAA Integrated Ocean Observing System (IOOS) Program Office. M. Le Hénaff received partial support for this work from the base funds of the NOAA Atlantic Oceanographic and Meteorological Laboratory and was supported in part under the auspices of the Cooperative Institute for Marine and Atmospheric Studies (CIMAS) , a cooperative institute of the University of Miami and NOAA , cooperative agreement NA10OAR4320143 . The Chlorophyll-a data were derived from ocean color images collected by the NASA Moderate Resolution Imaging Spectroradiometer (MODIS), were obtained from NASA's Ocean Biology Processing Group, and were further processed and distributed by the University of South Florida's Institute for Marine Remote Sensing ( http://data.imars.marine.usf.edu ). The MUR Global High-Resolution SST dataset is distributed by NASA ( http://podaac.jpl.nasa.gov/dataset/JPL-L4UHfnd-GLOB-MUR ). The NOAA National Data Buoy Center data are publicly available ( www.ndbc.noaa.gov ). The river discharge data from USGS and the Army Corps of Engineers are distributed by the Gulf of Mexico Coastal Ocean Observing System (GCOOS, http://gcoos.tamu.edu/products/index.php/waterquality/river-discharge-data/ ). The R/V Oregon II cruise in June 2016 was supported by a collaboration between the NOAA National Marine Fisheries Service (NMFS) and the Southeast Area Monitoring and Assessment Program (SEAMAP) in the GoM. The cruise data are publicly available on the NOAA Nationial Centers for Environmental Information portal ( https://www.ncei.noaa.gov/ ), in the Oceans dataset. We thank L. Johns for useful suggestions that improved the manuscript. We are grateful to G. Schmahl, E. Hickerson, S. Gittings, and G. Sedberry of the NOAA National Marine Sanctuaries for their insightful comments in discussions leading to this manuscript. We are grateful to S. DiMarco of Texas A&M University for sharing observation data. We are grateful to the Flower Garden Banks National Marine Sanctuary managers, in particular M. Johnston, for fruitful discussions and their interest in the unique episode discussed herein, which led to organizing the 2016 Flower Garden Banks Localized Mortality Event Mini-Symposium (Galveston, TX, February 27–28, 2018). We thank two anonymous reviewers for their help in improving our manuscript.
Funding Information:
This paper is a result of research funded by the National Oceanic and Atmospheric Administration RESTORE Act Science Program under award NA15NOS4510226 to the University of Miami. It is a contribution to the Marine Biodiversity Observation Network (MBON) program. The work was partially supported by NASA grant NNX14AP62A ?National Marine Sanctuaries as Sentinel Sites for a Demonstration Marine Biodiversity Observation Network (MBON)? funded under the National Ocean Partnership Program (NOPP RFP NOAA-NOS-IOOS-2014-2003803 in partnership between NOAA, BOEM, and NASA), and the NOAA Integrated Ocean Observing System (IOOS) Program Office. M. Le H?naff received partial support for this work from the base funds of the NOAA Atlantic Oceanographic and Meteorological Laboratory and was supported in part under the auspices of the Cooperative Institute for Marine and Atmospheric Studies (CIMAS), a cooperative institute of the University of Miami and NOAA, cooperative agreement NA10OAR4320143. The Chlorophyll-a data were derived from ocean color images collected by the NASA Moderate Resolution Imaging Spectroradiometer (MODIS), were obtained from NASA's Ocean Biology Processing Group, and were further processed and distributed by the University of South Florida's Institute for Marine Remote Sensing (http://data.imars.marine.usf.edu). The MUR Global High-Resolution SST dataset is distributed by NASA (http://podaac.jpl.nasa.gov/dataset/JPL-L4UHfnd-GLOB-MUR). The NOAA National Data Buoy Center data are publicly available (www.ndbc.noaa.gov). The river discharge data from USGS and the Army Corps of Engineers are distributed by the Gulf of Mexico Coastal Ocean Observing System (GCOOS, http://gcoos.tamu.edu/products/index.php/waterquality/river-discharge-data/). The R/V Oregon II cruise in June 2016 was supported by a collaboration between the NOAA National Marine Fisheries Service (NMFS) and the Southeast Area Monitoring and Assessment Program (SEAMAP) in the GoM. The cruise data are publicly available on the NOAA Nationial Centers for Environmental Information portal (https://www.ncei.noaa.gov/), in the Oceans dataset. We thank L. Johns for useful suggestions that improved the manuscript. We are grateful to G. Schmahl, E. Hickerson, S. Gittings, and G. Sedberry of the NOAA National Marine Sanctuaries for their insightful comments in discussions leading to this manuscript. We are grateful to S. DiMarco of Texas A&M University for sharing observation data. We are grateful to the Flower Garden Banks National Marine Sanctuary managers, in particular M. Johnston, for fruitful discussions and their interest in the unique episode discussed herein, which led to organizing the 2016 Flower Garden Banks Localized Mortality Event Mini-Symposium (Galveston, TX, February 27?28, 2018). We thank two anonymous reviewers for their help in improving our manuscript.
PY - 2019/11/15
Y1 - 2019/11/15
N2 - Remotely sensed and in situ data, in tandem with numerical modeling, are used to explore the causes of an episode of localized but severe mortality of corals, sponges, and other invertebrates at the Flower Garden Banks (FGB) National Marine Sanctuary in July 2016. At about 190 km off the Texas coast, at the top the seamount in the East FGB, up to 82% of coral reef organisms were affected in a 1–2 m thick layer on the local seafloor at ∼23 m depth. Analysis of available data pointed to low levels of dissolved oxygen being the most likely contributing factor in the observed mortality (Johnston et al., 2019). Observations show that upwelling-favorable winds in June and July 2016 carried brackish and turbid coastal waters across the northwestern Gulf of Mexico continental shelf to the FGB. This plume of coastal water was the result of exceptionally high precipitation and local river run-off. Field data provide clear evidence of thin, localized, subsurface near-hypoxic layers immediately below this turbid, low salinity coastal plume. These mid-water layers extended over longer distances (30–40 km), and reached further offshore (∼100 km), than previously reported in the region, associated with large quantities of organic matter carried offshore by the brackish plume. The surface brackish layer was observed to cover the East FGB in satellite ocean color imagery and in situ salinity measurements in late June and July 2016. Model results and sparse observations on the shelf suggest that this surface layer was ∼20 m thick. It is expected that organic matter carried in the surface layer accumulated on the seafloor of the East FGB, which was just below the brackish plume. In the absence of ventilation, this led to the local formation of a bottom hypoxic layer, similar to what is observed on the Gulf of Mexico inner to mid-shelf every summer. The conditions experienced at FGB in July 2016 are likely to affect other reefs exposed to brackish plumes with high organic matter loads. The processes of physical connectivity by transport of material is critical for reef colonization and survival, but can also be fatal to coral ecosystems. The monitoring of coral reefs should take the threat of hypoxia due to distant sources of organic matter into account.
AB - Remotely sensed and in situ data, in tandem with numerical modeling, are used to explore the causes of an episode of localized but severe mortality of corals, sponges, and other invertebrates at the Flower Garden Banks (FGB) National Marine Sanctuary in July 2016. At about 190 km off the Texas coast, at the top the seamount in the East FGB, up to 82% of coral reef organisms were affected in a 1–2 m thick layer on the local seafloor at ∼23 m depth. Analysis of available data pointed to low levels of dissolved oxygen being the most likely contributing factor in the observed mortality (Johnston et al., 2019). Observations show that upwelling-favorable winds in June and July 2016 carried brackish and turbid coastal waters across the northwestern Gulf of Mexico continental shelf to the FGB. This plume of coastal water was the result of exceptionally high precipitation and local river run-off. Field data provide clear evidence of thin, localized, subsurface near-hypoxic layers immediately below this turbid, low salinity coastal plume. These mid-water layers extended over longer distances (30–40 km), and reached further offshore (∼100 km), than previously reported in the region, associated with large quantities of organic matter carried offshore by the brackish plume. The surface brackish layer was observed to cover the East FGB in satellite ocean color imagery and in situ salinity measurements in late June and July 2016. Model results and sparse observations on the shelf suggest that this surface layer was ∼20 m thick. It is expected that organic matter carried in the surface layer accumulated on the seafloor of the East FGB, which was just below the brackish plume. In the absence of ventilation, this led to the local formation of a bottom hypoxic layer, similar to what is observed on the Gulf of Mexico inner to mid-shelf every summer. The conditions experienced at FGB in July 2016 are likely to affect other reefs exposed to brackish plumes with high organic matter loads. The processes of physical connectivity by transport of material is critical for reef colonization and survival, but can also be fatal to coral ecosystems. The monitoring of coral reefs should take the threat of hypoxia due to distant sources of organic matter into account.
KW - Coastal flooding
KW - Connectivity
KW - Coral reef
KW - Ecology
KW - Hypoxia
KW - Shelf processes
KW - Upwelling
UR - http://www.scopus.com/inward/record.url?scp=85073919648&partnerID=8YFLogxK
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U2 - 10.1016/j.csr.2019.103988
DO - 10.1016/j.csr.2019.103988
M3 - Article
AN - SCOPUS:85073919648
VL - 190
JO - Continental Shelf Research
JF - Continental Shelf Research
SN - 0278-4343
M1 - 103988
ER -