title: Opening of the closed water area and consequent changes of ²²⁸Ra/²²⁶Ra activity ratios in coastal lagoon Nakaumi, southwest Japan.
abstract: In Lake Nakaumi, the second largest coastal lagoon in Japan, artificially closed (Honjyo) area, which was left untouched for 28 years, was partly opened in May, 2009. (228)Ra/(226)Ra ratio of waters in Honjyo area and Lake Nakaumi showed a well-tuned seasonal variation exhibiting high value in summer. After the opening event, however, the (228)Ra/(226)Ra ratios in the Honjyo water showed an unclear seasonal variation in both surface and deep water. This opening event caused the change of active movement of lake and marine water.
authors.affiliation: Foraminiferal Laboratory, Faculty of Education, Shimane University, Matsue 690-8504, Japan. nomura@edu.shimane-u.ac.jp
authors.forename: Ritsuo
authors.initials: R
authors.lastname: Nomura
authors.forename: Kosaku
authors.initials: K
authors.lastname: Nakamura
authors.forename: Koji
authors.initials: K
authors.lastname: Seto
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Inoue
authors.forename: Hisaki
authors.initials: H
authors.lastname: Kofuji
mesh_terms: D007564:Japan; D060106:Lakes / Q000032:analysis* / Q000737:chemistry*; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000706:statistics & numerical data*; D011886:Radon / Q000032:analysis*; D012621:Seasons; D014878:Water Pollution, Radioactive / Q000032:analysis* / Q000706:statistics & numerical data*
chemical_list: D011886:Radon
keywords: (228)Ra/(226)Ra ratio; Brackish water lake; Reshaping of nature