St. Petersburg Coastal and Marine Science Center
Florida Shelf Geochemistry
Enhancement of Satellite Maps of Carbon Fluxes and Saturation State
Currently global warming and ocean acidification models attempt to predict changes in the geochemistry of pelagic (deep open ocean) waters in response to increasing concentrations of atmospheric CO2. These models do not apply to coastal systems due to the dynamic nature of coastal marine systems, which is driven by high rates of biological and geochemical processes over brief spatial and temporal scales relative to pelagic waters. High variability in coastal waters is due to respiration processes of benthic communities, high inputs of fresh water from streams and groundwater sources, high inputs of organic carbon and nutrients from surface and groundwater, temperature and salinity fluctuations, and increased pCO2 concentrations in air forced seaward from land. Field data, collected in the nearshore, can be used to improve current ocean acidification models. The USGS is partnering with NOAA to enhance regional models and the application of satellite imagery to the monitoring and understanding of ocean acidification on the Florida shelf.
Satellite data provide synoptic views of carbon fluxes and carbonate saturation states on the Florida shelf but have been limited to offshore applications. Field data and ground truthing can provide the spatial and temporal detail necessary to resolve the nearshore variability absent from satellite data. A combination of approaches will provide a more accurate model of temporal and spatial variability of carbon fluxes and ocean saturation of carbonate.
The degree to which seawater is supersaturated with respect to the carbonate minerals (e.g., aragonite or calcite) is an important parameter to help document the potential effects of ocean acidification on calcification rate. As ocean acidification continues, the surface ocean carbonate values will decline and will be deleterious to many of the marine calcifiers that precipitate calcium carbonate to build their skeletons. The data developed will provide the baseline for understanding the variability of the nearshore carbon fluxes and carbonate saturation states on the Florida shelf.
The partnership between USGS and NOAA is developing a regionally specific algorithm coupled to satellite and modeled data sets to generate fields of air and sea surface pCO2, pCO2 flux, alkalinity, and sea-surface aragonite saturation state on the Florida shelf. The USGS field campaign will provide regional coverage of the west Florida shelf. A robust, and regionally specific algorithm for sea surface alkalinity will enhance the current pCO2 algorithm, originally developed specifically for the Caribbean. Field data will also be used to link to data collected by the R/V Gordon Gunter cruises to fill-in data gaps. Daily data of carbon dioxide partial pressure (pCO2,sw) will be calculated by NOAA National Environmental Satellite, Data, and Information Service (NESDIS) through the application of modeled and remotely sensed environmental parameters. The coarse-scale model will be enhanced by the USGS field data and extended to the nearshore zone, for which previously no data existed for calibration of the model.