St. Petersburg Coastal and Marine Science Center
Generally stated, ocean acidification refers to the ongoing decrease in the pH of the oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere. Since the 1700s the surface ocean pH has been estimated to have decreased by 0.075. Scientific data indicates that a continued decrease in pH has the potential for affecting fundamental geochemical and biological processes in some plant and animal communities. For example, increased CO2 in coastal waters will lower the pH, reducing the availability of chemical compounds essential to shell creation and, ultimately, impact sediment production. The effects of changes in carbonate chemistry equilibrium will be dramatic in coastal systems where the majority of carbonate shell development and carbonate-based sediment production occurs. The effects on the diversity and distribution of benthic communities and sediment production are not known, but significant scientific efforts are being applied to develop climate change models. The results will be used by regulatory and science-based organization in making informed decisions on possible remediation efforts.
On-going laboratory experiments subject different calcifying organisms (green and red algae, foraminifera) to pH and saturation state changes in order to evaluate responses in carbonate production. Fieldwork focuses on collecting and examining baseline carbon and carbonate chemistry data (including carbonate saturation state). These data are used in conjunction with satellite data to provide a synoptic view of how the shelf is responding yearly and seasonally to long-term trends in pH. Historical data records from the State of Florida and USGS are being analyzed for long-term trends in pH, temperature, and salinity. These data will provide important information for predictive models on how climate change will affect shallow-water shellfish beds.