Ocean acidification monitoring
along the Georgia coast
Center for Applied Isotope Studies
University of Georgia
Tuesday, October 10, 2017
Pacific Forum—11:00 a.m.
The Grays Reef time-series mooring is a multi-organization effort that has successfully collected high-resolution water quality data since 2006. The mooring is located in the South Atlantic Bight offshore Georgia within Gray’s Reef National Marine Sanctuary (GRNMS). Based on the surface data collected, temperature-driven seasonal partial pressure of carbon dioxide (pCO2) changes occur naturally on an annual scale. The data suggest that seawater pCO2 is increasing faster than atmospheric pCO2 indicating there are additional CO2 sources adding to the carbon budget.
To support the surface monitoring and benthic studies at GRNMS, a seafloor observatory monitoring ocean acidification was established. Given the relatively shallow depth at GRNMS, it was thought pCO2 measured on the surface could be extrapolated to the seafloor. However, seafloor pCO2 data revealed unusual episodes of subsurface pCO2-rich water that had not been previously identified. These events correspond with major storms along the coast. Additionally, freshwater plumes from rivers can push offshore during heavy rain events. These plumes can have pCO2 up to 10 times that of offshore waters adding to the carbon budget. How the increasing seawater pCO2 will affect the benthic community has yet to be determined, but it is clear that the benthic organisms have adapted to the natural seasonal fluctuations for survival.
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