Historical record of nuclear activities from 129I in corals from the northern hemisphere (Philippines)

Bautista, Angel T.; Matsuzaki, Hiroyuki; Siringan, Fernando P.

doi:10.1016/j.jenvrad.2016.07.022

Cited by 36 publications

(25 citation statements)

References 25 publications

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“…The 129 I in the sediment core collected in Jiaozhou Bay in the YS has recorded a small but obvious PPG derived signal of 129 I in 195727. Meanwhile, a similar 129 I peak occurred in 1957–1958 in coral samples collected in the coastal region in Philippine has also been reported30, which suggests that PPG derived 129 I might have a contribution to 129 I in the ECS. However, the distribution of 129 I in the ECS shows the lowest 129 I level in the east edge of the ECS, i.e.…”

Section: Discussionmentioning

confidence: 67%

129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement

Liú

Hou

et al. 2016

Sci Rep

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Anthropogenic 129I as a long-lived radioisotope of iodine has been considered as an ideal oceanographic tracer due to its high residence time and conservative property in the ocean. Surface water samples collected from the East China Sea (ECS) in August 2013 were analyzed for 129I, 127I and their inorganic chemical species in the first time. The measured 129I/127I ratio is 1–3 orders of magnitude higher than the pre-nuclear level, indicating its dominantly anthropogenic sources. Relatively high 129I levels were observed in the Yangtze River and its estuary, as well as in the southern Yellow Sea, and 129I level in seawater declines towards the ECS shelf. In the open sea, 129I and 127I in surface water exists mainly as iodate, while in Yangtze River estuary and some locations, iodide is dominated. The results indicate that the Fukushima nuclear accident has no detectable effects in the ECS until August 2013. The obtained results are used for investigation of interaction of various water masses and water circulation in the ECS, as well as the marine environment in this region. Meanwhile this work provides essential data for evaluation of the possible influence of the increasing NPPs along the coast of the ECS in the future.

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Section: Discussionmentioning

confidence: 67%

129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement

Liú

Hou

et al. 2016

Sci Rep

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“…These high 14 C contents are thought to have been transported directly from the US Pacific Proving Grounds through the NEC, the KC, and the MC as ''close-in fallout'' [Kellogg et al, 1957;Fallon and Guilderson, 2008;Glynn et al, 2013;Andrews et al, 2016] because the operations were performed within only a few years and the data cannot be explained by 14 CO 2 absorption though air-sea CO 2 exchange. Bautista et al [2016] and Chang et al [2016] also reported iodine-129 in the corals collected from South China Sea and Guam originated from 1950s nuclear operations in the US Pacific Proving Grounds derived via the circulation of the North Pacific Gyre. Although their resolution is coarser than that from the present study, three independent results confirmed oceanographic transportation pathways of these nuclides.…”

Section: Discussionmentioning

confidence: 93%

“…Bautista et al . [] and Chang et al . [] also reported iodine‐129 in the corals collected from South China Sea and Guam originated from 1950s nuclear operations in the US Pacific Proving Grounds derived via the circulation of the North Pacific Gyre.…”

Section: Discussionmentioning

confidence: 99%

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

Hirabayashi

Yokoyama

Suzuki

et al. 2017

Geochem Geophys Geosyst

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High‐resolution measurements of radiocarbon (14C) in corals can be used to reconstruct past variability in ocean conditions. Here we report seasonal Δ14C changes in coral from Ishigaki Island, Japan, and compare with previously reported data from Palau and Guam. Our data clearly indicate a significant increase in Δ14C from 1947 to 1998 related to atmospheric nuclear bomb testing. The three early Δ14C spikes related to the atmospheric nuclear bomb tests in the US Proving Grounds at Bikini and Enewerak atoll conducted in 1954, 1956, and 1958 were detected from the Ishigaki coral. After 1976, variability in the Mindanao Dome region related to North Equatorial Current (NEC) bifurcation latitude migration affected the Δ14C difference between Palau and Guam, whereas the difference between Ishigaki and Guam was not correlated with the bifurcation latitude. The Δ14C difference between Ishigaki and Guam may be due to mesoscale eddies in the Kuroshio area. On the decadal scale, the northward shift of NEC bifurcation latitude after 1976, the year as known as Pacific Decadal Oscillation regime shift from negative to positive, was concurrent with the abundant westward‐propagating mesoscale eddies in the Subtropical Countercurrent region and stronger Kuroshio transport off the east Taiwan, which may be represented by a smaller Δ14C difference between Ishigaki and Guam after 1976.

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“…129 I bomb peak recorded in the corals are less influenced by oceanic process (Bautista et al 2016), while 14 C bomb curve varies both in timing and magnitude among different coral locations, depending on local differences in the air-sea CO 2 exchange rate and physical oceanic processes (Druffel 2002;Grottoli and Eakin 2007).…”

Section: Introductionmentioning

confidence: 94%

“…However, post-bomb 14 C data are scarcely available for the SCS (e.g., Mitsuguchi et al 2007;Shen et al 2003). Recent studies employed Iodine-129 ( 129 I) in coral skeleton obtained from SCS as a tracer of 1950s nuclear bomb test (Bautista et al 2016;Chang et al 2016 (Chang et al 2016). This can be attributed to the residence times of those nuclides namely ~2 years and ~10 years, respectively, for 129 I and 14 C in the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Radiocarbon variability recorded in coral skeletons from the northwest of Luzon Island, Philippines

et al. 2017

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The North Equatorial Current (NEC) bifurcates at the eastern coast of the Philippines and moves northward as the Kuroshio, a North Pacific western boundary current. The NEC bifurcation point and Kuroshio variability are known to be affected by changes in climate such as the El Niño-Southern Oscillation and the pacific decadal oscillation. However, observational data are not sufficient to examine the mechanisms of decadal fluctuation. Here, we report seasonal radiocarbon data recorded from 1968 to 1995 in coral skeletons northwest of Luzon Island. The data suggest that the East Asian winter monsoon is a dominant factor in the seasonal fluctuations in water mass northwest of Luzon Island. Compared with other coral records reported for Guam, Ishigaki, Con Dao, and Hon Tre Island, the data suggest that the area of the Kuroshio loop current through the Luzon Strait decreased from the 1970s to 1980s as a result of the change in Kuroshio transport and the migration of the NEC bifurcation latitude after a regime shift in 1976.

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Historical record of nuclear activities from 129I in corals from the northern hemisphere (Philippines)

Cited by 36 publications

References 25 publications

129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement

129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement

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

Radiocarbon variability recorded in coral skeletons from the northwest of Luzon Island, Philippines

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