title: Temporal variation of cesium isotope concentrations and atom ratios in zooplankton in the Pacific off the east coast of Japan.
abstract: After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, concentrations of cesium isotopes (133Cs,134Cs, and137Cs) were measured in zooplankton collected in the Pacific off the east coast of Japan from May 2012 to February 2015. The time series of the data exhibited sporadic137Cs concentration peaks in zooplankton. In addition, the atom ratio of137Cs/133Cs in zooplankton was consistently high compared to that in ambient seawater throughout the sampling period. These phenomena cannot be explained fully by the bioaccumulation of137Cs in zooplankton via ambient seawater intake, the inclusion of resuspended sediment in the plankton sample, or the taxonomic composition of the plankton. Autoradiography revealed highly radioactive particles within zooplankton samples, which could be the main factor underlying the sporadic appearance of high137Cs concentrations in zooplankton as well as the higher ratio of137Cs/133Cs in zooplankton than in seawater.
authors.affiliation: Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Ikenoue
authors.affiliation: Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan.
authors.forename: Hyoe
authors.initials: H
authors.lastname: Takata
authors.affiliation: Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kusakabe
authors.affiliation: Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Kudo
authors.affiliation: Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hasegawa
authors.affiliation: Marine Ecology Research Institute, Tohwa-Edogawbashi Bldg., 347 Yamabuki-cho, Shinjuku-ku, Tokyo 162-0801, Japan.|Department of Marine Science, Tokyo University of Marine Science and Technology, 5-7, Konan 4, Minato-ku, Tokyo 108-8477, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishimaru
mesh_terms: D000818:Animals; D002587:Cesium Isotopes / Q000737:chemistry; D002588:Cesium Radioisotopes / Q000737:chemistry; D062406:Fukushima Nuclear Accident; D019015:Geologic Sediments / Q000737:chemistry; D007564:Japan; D010140:Pacific Ocean; D012623:Seawater / Q000032:analysis; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D015048:Zooplankton / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002587:Cesium Isotopes; D002588:Cesium Radioisotopes; D014875:Water Pollutants, Radioactive; C000614989:Cesium-137