Table of Contents

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

High pressure liquid chromatography analyses of photosynthetic pigments taken on the R/V Acadian and R/V Pelican from September to October 2017 in the Central northern Gulf of Mexico.

These data have been published in NASA SeaBASS Data Archive:

• https://seabass.gsfc.nasa.gov/archive/UMASS_D/lohrenz/NSF_Gulf_Rapid/AC18_12_Roberts/archive/  
• https://seabass.gsfc.nasa.gov/archive/UMASS_D/lohrenz/NSF_Gulf_Rapid/PE18-11/archive/

Seawater samples for pigment analyses were immediately filtered (2 to 5 l volume) onto Whatman 47 mm GF/F filters under low vacuum (<0.5 atm). The filters were blotted dry, and stored in 2 ml cryotubes (Fisher) in liquid nitrogen until analysis. Analyses were performed within 6 months to a year of sampling.

Extraction procedures and HPLC analytical methods follow those described in Thomas (2012) and HPLC_Method_Summary.pdf (see related files and publications). 

HPLC samples were analyzed during August-September 2018 at the Horn Point Analytical Laboratory by Meg Maddox (mmaddox@umces.edu). Values of -8888 indicate concentrations that were below detection levels. Values of -9999 indicate missing data. Coefficient of variation (replicate filter precision) for all NSF_Gulf_Rapid_HPLC samples was TChl a = 3.09%; Ppig = 4.28%.

The HPLC was controlled by Agilent Chemstation software.

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.