The United States Geological Survey (USGS) is studying the effects of climate change on ocean acidification within the Gulf of Mexico; dealing specifically with the effect of ocean acidification on marine organisms and habitats. To investigate this, the USGS participated in cruises on the West Florida Shelf and northern Gulf of Mexico regions aboard the research vessel (R/V) Weatherbird II or Bellows, ships of opportunity led by Dr. Kendra Daly, of the University of South Florida (USF) in July and August, 2013. Cruises left from and returned to Saint Petersburg, Florida, but followed different routes. The USGS collected geochemical data pertaining to pH, dissolved inorganic carbon (DIC), total carbon dioxide (TCO2), and total alkalinity (TA) in discrete samples at various depths from predetermined stations. Discrete surface samples were also taken, while in transit, during both cruises.