Grain size and radiometric data from multi-core sediments collected Fall 2017 from the R/V Acadiana in the northwestern Gulf of Mexico to assess Hurricane Harvey impacts

Data Type: Cruise Results
Version: 1
Version Date: 2020-09-22

» Collaborative Research: A RAPID response to Hurricane Harvey's impacts on coastal carbon cycle, metabolic balance and ocean acidification (HarveyCarbonCycle)
Maiti, KanchanLouisiana State University (LSU)Principal Investigator
Gerlach, Dana StuartWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Sediments of the northwestern Gulf of Mexico were analyzed for grain size and radiometric data (210-Pb, 234-Th, and 7-Be) to assess Hurricane Harvey impacts.


Spatial Extent: N:29.325 E:-90.2333 S:28.217 W:-95.2561
Temporal Extent: 2017-09-18 - 2017-10-09

Acquisition Description

Samples were collected from the Louisiana-Texas shelf in the Gulf of Mexico using the ship R/V Acadiana. Sediment cores were obtained using a multi corer and subsampled at 2 cm depth intervals. 

Sediment core subsamples were dried, homogenized, and subsequently analyzed.  Grain size distribution was determined using laser diffraction after deflocculation in a 0.05% sodium metaphosphate solution, and disaggregation with an ultrasonic probe (Denommee et al., 2016).  Radiometric data (210Pb, 234Th, and 7Be) were obtained using gamma spectroscopy (Maiti et al., 2010).  

Processing Description

BCO-DMO processing notes:
- Adjusted parameter names to comply with database requirements
- Rounded values to submitter's preferred precision
- Units added to Parameter description metadata section
- Added a conventional header with dataset name, PI name, version date. 

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Related Publications

Denommee, K. C., Bentley, S. J., Harazim, D., & Macquaker, J. H. S. (2016). Hydrodynamic controls on muddy sedimentary-fabric development on the Southwest Louisiana subaqueous delta. Marine Geology, 382, 162–175. doi:10.1016/j.margeo.2016.09.013
Maiti, K., Carroll, J., & Benitez-Nelson, C. R. (2010). Sedimentation and particle dynamics in the seasonal ice zone of the Barents Sea. Journal of Marine Systems, 79(1-2), 185–198. doi:10.1016/j.jmarsys.2009.09.001

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ISO_DateTime_UTCUTC datetime in ISO format (yyyy-mm-dd hh:mm:ss) unitless
LatitudeLatitude decimal degrees
LongitudeLongitude, west is negative decimal degrees
Be7_InventoryInventory of Beryllium-7 disintegrations per minute per centimeter squared (dpm/cm^2)
Pb210ex_InventoryInventory of excess (unsupported) Lead-210 disintegrations per minute per centimeter squared (dpm/cm^2)
Th234ex_InventoryInventory of excess Thorium-234 disintegrations per minute per centimeter squared (dpm/cm^2)
Be7_DepthPenetration depth of Be-7 detection centimeters (cm)
ClaySediment grain size in the clay fraction percent (%)
SiltSediment grain size in the sand fraction percent (%)
SandSediment grain size in the silt fraction percent (%)

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Dataset-specific Instrument Name
Beckman-Coulter LS13 320 Laser Diffraction Particle-Size Analyzer
Generic Instrument Name
Laser Diffraction Particle Size Analyzer
Dataset-specific Description
The Beckman Coulter LS 13 320 measures the size distribution of particles suspended either in a liquid or in dry powder form by using the principles of light scattering.  Each particle's scattering pattern is characteristic of its size. The pattern measured by the LS 13 320 is the sum of the patterns scattered by each constituent particle in the sample.The LS 13 320 incorporates Beckman Coulter's patented PIDS (Polarization Intensity Differential Scattering) technology to provide a dynamic range of 0.017 μm to 2000 μm.  (More details in the manual,
Generic Instrument Description
Laser diffraction is particle sizing technique for materials ranging from hundreds of nanometers up to several millimeters in size. Laser diffraction measures particle size distributions by measuring the angular variation in intensity of light scattered as a laser beam passes through a dispersed particulate sample. One example is the Beckman Coulter LS200.

Dataset-specific Instrument Name
Canberra Germanium Well Detectors GCW3523 and GCW4023
Generic Instrument Name
Gamma Ray Spectrometer
Dataset-specific Description
The CANBERRA High-Purity Germanium Well Detector provides maximum efficiency for small samples and allows spectroscopy from 20keV up to 10MeV.  (More details in manual,
Generic Instrument Description
Instruments measuring the relative levels of electromagnetic radiation of different wavelengths in the gamma-ray waveband.

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Project Information

Collaborative Research: A RAPID response to Hurricane Harvey's impacts on coastal carbon cycle, metabolic balance and ocean acidification (HarveyCarbonCycle)

Coverage: Northwestern Gulf of Mexico

NSF Award Abstract:
Understanding how extreme events, like hurricanes, impact coastal ecosystems and the cycling of elements like carbon and oxygen, is important for improving our ability to predict how the global carbon cycle will respond to climate. This team of investigators, who have already been working together on understanding the carbon cycle in the Gulf of Mexico continental shelves, have important recent data against which to measure the effects of the passage of Hurricane Harvey in August, 2017. They will sample the waters and sediments of the northwestern Gulf of Mexico in September, October, and January to assess Harvey's impacts on a timescale of weeks to months.

The researchers pose three specific questions: 1. Will the region become a major source of carbon dioxide to the atmosphere, releasing carbon accumulated in the bottom water and sediments, and will this potential impact be faster and greater than during normal fall and winter mixing events? Will this process acidify the surface water and for how long? 2. Will the metabolic balance be substantially pushed toward net heterotrophy as a result of the storm in comparison to other years? 3. Can the amount of material delivered or redeposited across the continental shelf by a tropical cyclone be considerably larger than that related to winter storm systems? The PIs will measure water column nutrients, oxygen, organic carbon, and inorganic carbon system parameters; determine water column and benthic metabolic and nutrient flux rates; and sediment organic matter deposition rates. They will also collect end member river samples. They will compare the immediate (mid-Sept) but limited post-hurricane data and one-month post-hurricane, more detailed data with those collected in July and April to study the impacts of the storms. they will also compare 2017-2018 seasonal data to seasonal data over the same region collected in the past (2006-2008 and 2009-2010). They will also compare the impacts of Hurricane Harvey to those of Hurricanes Katrina and Rita (2005) and Tropical Storm Cindy (June 2017). The project will involve graduate and postdoctoral research and work to communicate results to the public.

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Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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