Development of the microscale stable isotope analytical technique of carbonate in fish hardparts for temperature reconstruction

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21343
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: NISHIDA Kozue 筑波大学, 生命環境系, 特任助教 (10708374)
• Co-Investigator(Kenkyū-buntansha): 石村 豊穂 京都大学, 人間・環境学研究科, 准教授 (80422012) ; 白井 厚太朗 東京大学, 大気海洋研究所, 准教授 (70463908)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 安定同位体比 / 魚類 / 構造炭酸塩 / 温度復元 / 骨 / リン酸カルシウム

Outline of Final Research Achievements

The hard tissues of vertebrate bones and teeth are predominantly composed of phosphate and contain a few percent of carbonate groups called structural carbonates. Stable oxygen isotope ratios of structural carbonates record habitat temperature and oxygen isotope ratios of ambient water in the case of metazoans and body temperature and oxygen isotope ratios of ambient water in the case of thermostatic animals. If it becomes possible to reconstruct environmental and ecological history using stable isotope ratios of structural carbonate, we can unravel unknown histories of behavioral ecology in animals. In this study, we investigated the carbon and oxygen isotope compositions of structural carbonates in fish bones, which have not been studied before, and found their usefulness as environmental and ecological indicators by examining pretreatment and analytical methods.

Free Research Field

地球化学

Academic Significance and Societal Importance of the Research Achievements

脊椎動物の骨や歯の硬組織はリン酸塩を主成分とし、数%の炭酸基を含んでいる。これを構造炭酸塩と呼び、構造炭酸塩の酸素安定同位体比は生息環境の温度や環境水を記録するので、その積極的な活用が可能になれば新たな生態情報の抽出が実現できる。本研究は、魚類における骨の構造炭酸塩の安定同位体比分析法を検証し、環境・生態履歴を復元する手法を新たに提案した。骨の構造炭酸塩の酸素同位体比は、温度とよい相関を示し、温度指標として骨の構造炭酸塩を活用できることを提示できた。本研究は魚類の構造炭酸塩の同位体比から環境履歴の情報を取得する手法を提案し、回遊経路推定など水産資源管理への貢献が期待される。