Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Sediments of the northwestern Gulf of Mexico were analyzed for grain size and radiometric data (²¹⁰Pb, ²³⁴Th, and ⁷Be) to assess Hurricane Harvey impacts. Samples were collected from the Louisiana-Texas shelf in September and October 2017 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).  

BCO-DMO processing notes:
- Converted datetimes to ISO8601 format (UTC format)
- Adjusted parameter names to comply with database requirements
- Rounded values to submitter's preferred number of digits
- Units added to Parameter description metadata section
- Added a conventional header with dataset name, PI name, version date. 

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.