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2011 Shelfwide Cruise: July 25 - August 6

Research Objectives

  • Mapping the extent of hypoxic water (< 2 mg/L) across the Louisiana and Texas inner to mid continental shelf, along with associated physical, chemical, and biological parameters. Associated rate measurements of biogeochemical processes.

Routine Measurements

  • There are 80 to 100 stations from the Mississippi River delta on the east of the study area westward to the adjacent Texas coast south of Galveston. Additional stations have been added to this year's cruise at least to Matagorda Bay, TX due to the expected greater extent of hypoxia and the SEAMAP cruise documented hypoxia in that area.
  • Standard hydrographic casts with a SeaBird CTD/rosette sampler for depth, temperature, salinity, dissolved oxygen, in vivo fluorescence, photosynthetically active radiation, percent transmission, optical backscatter. Additional hydrocast with YSI 6820 for close-to-bottom and near-surface measurements of depth, temperature, salinity, dissolved oxygen, and pH. Additional light meter cast for temperature, percent transmission, and % PAR. Calibration of salinity with discrete samples for analysis on PortaSal; calibration of oxygen with Winkler titrations. Instruments pre- and post-calibrated according to manufacturer guidelines. And the forever consistent, historical collection of Secchi disk depth.
  • Discrete depth sampling from 5-L Niskin bottles on the CTD/rosette for nutrients, chlorophyll biomass, suspended sediments (organic and inorganic), phytoplankton, HPLC phytopigments.
  • Underway mapping of current speed and direction through the water column with Acoustic Doppler Current Profiler systems.
  • Underway mapping of near surface water temperature, salinity, in vivo fluorescence, percent transmission, pCO2, georeferenced with navigation data and suite of meteorological measurements (Multiple Integrated Data Assimilation System, MIDA


  • Oxygen isotopes, respiration measurements
  • N2/Ar ratios (denitrification) and organic matter (POM/DOM) distributions;
  • Surface pCO2 underway, surface and bottom total alkalinity, pH, DIC
  • Zooplankton distributions with a Lazer Optical Plankton Counter (LOPC), calibrated with Niskin samples and net tows
  • Pseudo-nitzschia and domoic acid toxicity at different oxygen levels
  • Phytoplankton growth limitation, sulfide concentration in bottom waters
  • Sediment cores for paleoindicators of productivity and oxygen stres

Principal Investigators

  • Nancy Rabalais, Louisiana Universities Marine Consortium
  • Brian Roberts, Louisiana Universities Marine Consortium
  • Geoff Sinclair, Louisiana Universities Marine Consortium
  • Gene Turner, Louisiana State University
  • Dubravko Justic, Louisiana State University
  • Chunyan Li, Louisiana State University
  • Brian Fry, Louisiana State Unviersity
  • Don Scavia, University of Michigan


National Oceanic and Atmospheric Administration, Center for Sponsored Coastal Ocean Research, NGOMEX09: Integrated Ecosystem Modeling of the Causes of Hypoxia (Rabalais et al.), grant numbers NA09NOS4780204 to Louisiana Universities Marine Consortium and NA09NOS4780230 to Louisiana State University


  • The final dissolved oxygen data will be corrected, as necessary, from linear regression with the Winkler titrations over a range of 0.22 to 8.43 mg/L. Initial observations indicate correction, but the f-factor for the Winkler standard remains to be verified. Any corrected data will be reflected in other derived measurements.
  • Salinity data not yet verified with PortaSal samples.
  • CTD data remain to be post-processed with ALIGN CTD to be applied.
  • Instrumentation was calibrated pre- and post-cruise according to manufacturer's specifications and standard method procedures were applied for several variables, not yet calculated, according to several LUMCON EPA-approved Quality Assurance Project Plans.
  • Data collected as part of process studies remain to be analyzed and synthesized.
  • Final QA/QC'd data will be submitted to NOAA NODC within two years of collection.