NGOM-HYPOXIA-2027

Aseries of hydrographic stations for CTD and Water collection. These data are supplied to the NCEIS and the federal/state Hypoxia Task Force for inclusion into their long-term data base dating from 1985. Hydrographic profiles will be collected using the R/V Pelican’s SeaBird 911+ CTD unit equipped with pressure sensor, altimeter, redundant pumped temperature, conductivity and dissolved oxygen sensors, % transmission, PAR and in vivo fluorescence for estimate of chlorophyll biomass. The PI will bring an EXO3 for close-to-bottom dissolved oxygen (DO) measurements and as a backup instrument if something happens to the CTD during the cruise.Oxygen titrations using the Winkler method will be used to pre-cruise check the various oxygen sensors, and post-calibrate, if necessary, the dissolved oxygen from the SeaBird CTD or the EXO3. Post cruise cross-checks of salinity will also be conducted on the two instruments’ conductivity probes for post-calibration, if necessary. Underway data from the R/V Pelican will be collected and coupled with integrated data for GPS navigational, meteorological (wind speed and direction, barometric pressure, air temperature, relative humidity and photosynthetically active radiation (PAR)), and sea surface hydrographic (temperature, conductivity, % transmission, and in vivo fluorescence) data.