Department of Earth System Science

Radiocarbon measurements on a 175-year (A.D. 1800 to 1974) growth of the coral Montastrea annularis from The Rocks reef off the Florida Keys reveal the rate of local uptake of fossil fuel CO₂ and bomb ¹⁴C by surface ocean waters of the Gulf Stream. In the nineteenth century, the pre-bomb, pre-industrial Δ¹⁴C value of surface ocean waters as seen in these corals of the Gulf Stream in the Florida Straits was −51 ± 2‰. By 1955, uptake of industrial CO₂ by these waters had lowered the Δ¹⁴C values to about −61‰. The results can be used to make predictions regarding anthropogenic CO₂ that can be expected to enter the oceans in future decades. Bomb-produced ¹⁴C is found to be present in the corals in comparable concentrations to that found in the dissolved inorganic carbon (DIOC) of the North Pacific and North Atlantic Oceans.