Bomb Radiocarbon and the Suess Effect in Palmyra Corals During the Past 100 Years

Annual samples from Palmyra coral cores that lived from 1900 to 2007 were analyzed for radiocarbon (D14C) using accelerator mass spectrometry. Palmyra atoll (6N, 162W) is located near the boundary of the North Equatorial Counter Current and the South Equatorial Current in the Pacific Ocean, making it an interesting location for observing changes in Pacific climate, e.g. ENSO. These results show the input of bomb radiocarbon to the tropical Pacific beginning in the mid-1950s, where D14C values rose from ~ -55 to -60 per mil to ~ +100 per mil by 1980. The Suess effect, which is the decrease in D14C noticed by 1955, will be compared to that observed at other locations in the Pacific and Atlantic Oceans. The usefulness of the D14C record at Palmyra as an indicator of climate will be explored.