Increasing amounts of atmospheric carbon dioxide from human industrial activities are causing changes in global ocean carbon chemistry resulting in a reduction in pH, a process termed ocean acidification. In support of the coastal monitoring and research objectives of the NOAA Ocean Acidification Program (OAP), the South Florida Project Cruises (SFP) are utilized to collect water samples to measure surface water inorganic carbon and hydrographic parameters including nutrients. Samples are collected from 34 stations on a bi-monthly basis to monitor the outflow of the Shark River Slough (SRS) and red tide in the southwestern Gulf of Mexico. Water samples are sent to and analyzed by scientists at the Atlantic Oceanographic & Meteorological Laboratory (AOML) for dissolved inorganic carbon, pH, total alkalinity and nutrient concentrations. These data are used to observe the effects of the SRS on acidification in the coastal ocean.

This dataset includes high-frequency (hourly to sub-hourly) coastal acidification time-series data collected during nine deployments in the aforementioned seven estuaries along the US East Coast, US West Coast and Gulf of Mexico from 2015-04-23 to 2020-07-29. These data include water temperature, salinity, partial pressure of carbon dioxide (pCO2) in water, dissolved oxygen (DO) in water, and pH on the total scale. The instruments used to collected these data include Sunburst SAMI-CO2, Pro-Oceanus CO2-Pro CV and a LiCOr LI-820 CO2 gas analyzers for autonomous pCO2 measurements, Sea-Bird SeapHOx and SeaFET instruments for pH measurements, Sea-Bird SeapHOx and Aanderaa Oxygen Optode instruments for DO measurements, and YSI water sensing instrument packages for measurements of conductivity (salinity), temperature and depth. Beginning in 2015, the U.S. Environmental Protection Agency’s (EPA) National Estuary Program (NEP) started a collaboration with partners in seven estuaries along the East Coast (Barnegat Bay; Casco Bay), West Coast (Santa Monica Bay; San Francisco Bay; Tillamook Bay), and the Gulf of Mexico (GOM) Coast (Tampa Bay; Mission-Aransas Estuary) of the United States to expand the use of autonomous monitoring partial pressure of carbon dioxide (pCO2) and pH sensors to evaluate carbonate chemistry in the estuarine environment.

These datasets consist of profile data collected by CTD casts in the northern Gulf of Mexico that are collected as part of the annual summer groundfish survey supported by the Southeast Area Monitoring and Assessment Program (SEAMAP). SEAMAP is a State/Federal/university program for collection, management and dissemination of fishery-independent data and information in the southeastern United States. Data are in Sea-Bird CNV format.

Various water column variables, including salinity, dissolved inorganic nutrients, pH, total alkalinity, dissolved inorganic carbon, radio-carbon isotopes were measured in samples collected using a Niskin-bottle rosette at selected depths from sites offshore of California and Oregon from October to November 2018 during NOAA cruise SH-18-12 on the R/V Bell M. Shimada (USGS field activity 2018-663-FA). CTD (Conductivity Temperature Depth) data were also collected at each depth that a Niskin-bottle sample was collected and are presented along with the water sample data. This data release supersedes version 2.0, published in September 2021 at https://doi.org/10.5066/P99DIQZ5. Versioning details are documented in the accompanying VersionHistory_P99MJ096.txt file.