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| Titel |
Horizontal distribution of Fukushima-derived radiocesium in zooplankton in the northwestern Pacific Ocean |
| VerfasserIn |
M. Kitamura, Y. Kumamoto, H. Kawakami, E. C. Cruz, K. Fujikura |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 8 ; Nr. 10, no. 8 (2013-08-29), S.5729-5738 |
| Datensatznummer |
250085315
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| Publikation (Nr.) |
 copernicus.org/bg-10-5729-2013.pdf |
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| Zusammenfassung |
| The magnitude of the 9.0 Tohoku earthquake and the ensuing tsunami on
11 March 2011, inflicted heavy damage on the Fukushima Dai-ichi nuclear power
plant (FNPP1). Fission products were emitted, falling over a broad range in
the Northern Hemisphere, and water contaminated with radionuclides leaked
into the ocean. In this study, we described the horizontal distribution of
the Fukushima-derived radiocesium in zooplankton and in seawater in the
western North Pacific Ocean (500–2100 km from the FNPP1) 10 months after
the accident. 134Cs and 137Cs were detected in zooplankton and
seawater from all the stations. Because of its short half-life, the 134Cs
detected in our samples could only be derived from the FNPP1 accident. The
highest 137Cs activity in zooplankton was the same order of magnitude as
it was one month after the accident, and average activity was one or two
orders of magnitude higher than 137Cs activities observed before the
accident around Japan. Horizontally, the radiocesium activity concentrations
in zooplankton were high at around 25° N while those in surface
seawater were high at around the transition area between the Kuroshio and the
Oyashio currents (36–40° N). We observed subsurface radiocesium
maxima in density range of the North Pacific Subtropical Mode Water and the
occurrence of many diel vertical migratory zooplankton. These suggested that
the high activity concentrations in the subtropical zooplankton at around
25° N were connected to the subsurface radiocesium and active
vertical migration of zooplankton. However, the high activity concentrations
of radiocesium in subsurface seawater did not necessarily correlate with the
higher radiocesium activity in zooplankton. Activity concentrations of
radiocesium in zooplankton might be influenced not only by the environmental
radiocesium activity concentrations but also by other factors, which are
still unknown. |
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