@misc{oai:repo.qst.go.jp:00062786,
 author = {Kaeriyama, Hideki and Watanabe, Teruhisa and Kusakabe, Masashi and 帰山 秀樹 and 渡部 輝久 and 日下部 正志},
 month = {Oct},
 note = {The objective of this study is to obtain information on the background level of 137Cs in zooplankton in the waters close to Rokkasho-mura in Aomori Prefecture, Japan, where a large-scale project has been progressively promoted to establish the nuclear fuel cycle.   Prior to the full-scale operation of the spent nuclear fuel reprocessing plant, zooplankton samples were collected in May and October 2005, June 2006, and June 2007 from the surface water (0-50 m depth).  The samples were analyzed to determine the concentrations of 137Cs and stable Cs in relation to taxonomic composition.  The numerical abundance of the plankton varied from 253 to 1514 inds. m-3.  Taxonomic composition differed between the two sampling periods.  Although copepods formed the most abundant taxonomic group during both seasons, gelatinous plankton (chaetognaths, siphonophores, appendicularians and doliolids) were more abundant in October 2005 than in June 2006 and June 2007.  The concentration of 137Cs in zooplankton varied from 11 to 24 mBq kg-WW-1.  At the same station, the 137Cs concentration in zooplankton in October 2005 was almost twice as much as that in June 2006, although the concentration of 137Cs in seawater did not show a difference.  The concentration of stable Cs was measured for each taxonomic group: that in gelatinous zooplankton (chaetognaths) was higher than that in crustacean zooplankton (copepods, euphausiids and amphipods).  These results suggest that the concentration of 137Cs in zooplankton is affected by the occurrence of gelatinous zooplankton., The 16th Pacific Basin Nuclear Conference},
 title = {The concentration of 137Cs and stable Cs in zooplankton in the western North Pacific in relation to their taxonomic composition},
 year = {2008}
}