Radiocarbon in annual coral rings of Florida

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 CO 2 and bomb 14 C by surface ocean waters of the Gulf Stream. In the nineteenth century, the pre‐bomb, pre‐industrial Δ 14 C 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 CO 2 by these waters had lowered the Δ 14 C values to about −61‰. The results can be used to make predictions regarding anthropogenic CO 2 that can be expected to enter the oceans in future decades. Bomb‐produced 14 C 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.