Dissolved oxygen, temperature, salinity, and other variables measured and calculated from profile observations using CTD and other instruments from the NOAA Ship Ronald H. Brown in the Gulf of Mexico during the fourth Gulf of Mexico Ecosystems and Carbon Cycle (GOMECC-4) cruise from 2021-09-13 to 2021-10-21 (NCEI Accession 0284051)

The fourth Gulf of Mexico Ecosystems and Carbon Cycle (GOMECC-4) Cruise took place on board the NOAA Ship Ronald H. Brown, from September 13–October 21, 2021. The cruise departed from Key West, FL into the Gulf of Mexico and then around the coastal waters of the Gulf of Mexico in a counter-clockwise direction, ending in St. Petersburg, FL. The effort was in support of the coastal monitoring and research objectives of the NOAA Ocean Acidification Program (OAP). The cruise was designed to obtain a snapshot of key carbon, physical, biogeochemical and biological parameters as they relate to ocean acidification (OA) in the coastal realm. This was the fourth occupation of the Gulf of Mexico as part of OAP’s monitoring efforts in the region, with the previous ones occurring in 2007, 2012, and 2017. The cruise included a series of 15 transects approximately orthogonal to coast of the Gulf of Mexico and a 16th partial transect along the 27°N line, between Florida and the Bahamas, as well as a comprehensive set of underway measurements. This dataset includes the processed, 1db-binned CTD profile data collected in the 141 stations.