Multidecadal oceanographic changes in the western P acific detected through high‐resolution bomb‐derived radiocarbon measurements on corals

Researchers have detected significant multidecadal oceanographic changes in the western Pacific, particularly around Bikini Atoll, using high-resolution bomb-derived radiocarbon (14C) measurements on corals. The study identified three distinct early 14C spikes corresponding to nuclear tests conducted at Bikini and Enewetak atolls in 1954, 1956, and 1958. Post-1976, the data revealed that changes in the North Equatorial Current (NEC) bifurcation latitude, linked to the Pacific Decadal Oscillation regime shift, influenced radiocarbon differences between Palau and Guam but not between Ishigaki Island and Guam. The latter difference was attributed to mesoscale eddies in the Kuroshio area, suggesting complex oceanographic dynamics. This study highlights how bomb-derived 14C can serve as a proxy for reconstructing past ocean conditions.

Hirabayashi, S., Yokoyama, Y., Suzuki, A., Miyairi, Y., & Aze, T. (2017). Multidecadal oceanographic changes in the western Pacific detected through high‐resolution bomb‐derived radiocarbon measurements on corals. Geochemistry, Geophysics, Geosystems, 18(4), 1608–1617. Portico. https://doi.org/10.1002/2017gc006854