Portal de Periódicos da CAPES

Early Bomb Radiocarbon Detected in Palau Archipelago Corals

2013; Cambridge University Press; Volume: 55; Issue: 3 Linguagem: Inglês

10.1017/s0033822200048578

1945-5755

D. S. Glynn, Ellen R. M. Druffel, Sheila Griffin, Robert B. Dunbar, M. C. Osborne, Joan-Albert Sánchez-Cabeza,

Isotope Analysis in Ecology

In order to evaluate the variability in surface water masses in the Western Pacific Warm Pool, we report high-precision radiocarbon measurements in annual and seasonal bands from Pontes lutea corals collected from the Palau Archipelago (7°N, 134°E). Annual coral bands from 1945 to 2008 and seasonal samples from 1953 to 1957 were analyzed to capture the initial early input of bomb 14 C from surface thermonuclear weapons testing in the Marshall Islands. Results show a pre-bomb average δ 14 C value of-54.9% between 1945 and early 1953. Beginning early in 1954, there is a rapid increase to a maximum of-23.1% at the start of 1955. Values continued to rise after 1957 to a post-bomb peak of 141% by 1976. The large initial rise in δ 14 C cannot be accounted for by air-sea CO 2 exchange. Results therefore suggest that the primary cause of this increase is the lateral advection of fallout-contaminated water from the Marshall Islands to Palau via the North Equatorial Current and then to the North Equatorial Countercurrent.