Reconstruction of the temporal distribution of ²³⁶U/ ²³⁸U in the Northwest Pacific Ocean using a coral core sample from the Kuroshio Current area

Autor(en)

Tomoya Nomura, Aya Sakaguchi, Peter Steier, Rosmarie Eigl, Akane Yamakawa, Takaaki Watanabe, Keiichi Sasaki, Tsuyoshi Watanabe, Robin Golser, Yoshio Takahashi, Hiroya Yamano

Abstrakt

The temporal distribution of U-236 in the Northwest Pacific Ocean was reconstructed through measurements of the annual changes in U-236/U-238 atom ratios in a coral core collected from Kume Island located within the Kuroshio Current region. In total, 74 years (1940-2014) of temporal trend of U-236/U-238 atom ratios were reconstructed using Accelerator Mass Spectrometry (AMS). The annually resolved U-236/U-238 ratios showed a strong increase from 1952, and two prominent peaks were found in the annual bands for 1954 (11.0 +/- 1.2 x 10(-9)) and 1958 (8.55 +/- 1.17 x 10(-9)); also an enhanced peak was observed for the band of 1963 (3.51 +/- 0.20 x 10(-9)). These peaks coincided with the occurrence of large nuclear tests in the Pacific Proving Grounds and/or the highest global fallout rate, suggesting a clear influence of these nuclear events on U-236/U-238 atom ratios. Furthermore, the coral results showed some disagreement with the annual changes for U-236 in East Asian corals collected at the entrance to the Sea of Japan. Based on these results, the mixing ratios of the surface seawater currents in the Northwest Pacific Ocean have been estimated.

Organisation(en)

Isotopenphysik

Externe Organisation(en)

Hiroshima University, University of Tsukuba, National Institute for Environmental Studies, Hokkaido University, Kanazawa Gakuin University, University of Tokyo

Journal

Marine Chemistry

Band

190

Seiten

28-34

Anzahl der Seiten

7

ISSN

0304-4203

DOI

https://doi.org/10.1016/j.marchem.2016.12.008

Publikationsdatum

03-2017

Peer-reviewed

Ja

ÖFOS 2012

103014 Kernphysik, 105904 Umweltforschung, 105306 Ozeanographie

Schlagwörter

ASJC Scopus Sachgebiete

Water Science and Technology, Allgemeine Chemie, Oceanography, Environmental Chemistry

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/f469b653-2d1f-4f74-8ebc-f349b667040b