Implication to the sediment acidification in brackish water due to the change of sedimentation rate, and its improvement

2016 Fiscal Year Final Research Report

• Project/Area Number: 25287138
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Shimane University
• Principal Investigator: Nomura Ritsuo 島根大学, 教育学部, 教授 (30144687)
• Co-Investigator(Kenkyū-buntansha): 入月 俊明 島根大学, 総合理工学研究科(研究院), 教授 (60262937) ; 井上 睦夫 金沢大学, 環日本海域環境研究センター, 准教授 (60283090) ; 辻本 彰 島根大学, 教育学部, 講師 (60570554) ; 林 広樹 島根大学, 総合理工学研究科(研究院), 准教授 (80399360)
• Research Collaborator: TAKATA Hiroyuki 釜山国立大学, 海洋学部, 研究員
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 酸性化 / 汽水域 / 堆積速度 / 水循環 / 有機物負荷 / アンスロポシーン

Outline of Final Research Achievements

In order to clarify the acidification of brackish water, we carried out the measurements of sedimentation rate and dissolution of the meiobenthic calcareous foraminiferal tests in brackish lakes Shinjiko and Nakaumi. By using Pb-210 and Cs-137 methods, it was clarified that sedimentation rates and the processes are different in each side of the western and eastern Shinjiko. The change of sedimentation rate of organic matter occurred in the 1970's-80's in both lakes, and the decrease of Ra-226 transported by river from land occurred in the 1950's-60's. Dissolution of calcareous tests of foraminifera was distinct in lowered salinity. We confirmed that the dissolution of calcareous tests occurred in the high sedimentation and the high decomposition rates of organic matters, but the dissolution was buffered by marine water.

Free Research Field

地質学