Coral proxy archives infer relationships between climate changes and social stabilities in the Near East

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K13447
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 06020:International relations-related
• Research Institution: KIKAI institute for Coral Reef Sciences
• Principal Investigator: Watanabe Takaaki 特定非営利活動法人喜界島サンゴ礁科学研究所, 研究部門, 特別研究員 (00852310)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: サンゴ / オマーン / アラビア半島 / Sr/Ca比 / Ba/Ca比 / 酸素同位体比

Outline of Final Research Achievements

This research focused on reconstructing the past aridity and strong wind event with dust storms, so-called shamal, using the coral skeletal proxy. For accurate reconstruction, this study established a new method to calculate seawater oxygen isotope (for salinity proxy) and to analyze Ba/Ca ratio in the coral skeleton (for river runoff proxy). Furthermore, this study compared the present warm climate caused by anthropogenic forcing with the past warm climate caused by natural factors in order to examine whether the present environment in the Middle East region is unique or not. Using reef-building coral skeletons collected in northeastern Oman, this study reconstructed the strong wind event in the past warming era (ca 120 ka). The coral record revealed that the past winter monsoon and shamal wind was relatively stronger than the present.

Free Research Field

古気候・古海洋学

Academic Significance and Societal Importance of the Research Achievements

本研究では、サンゴ骨格を用いて古環境復元を行う際に最も頻繁に用いられる指標の１つである塩分指標の新たな計算方法を確立することに成功した。また、過去の洪水や干ばつを復元することができる河川流量指標の簡便かつ低コストな分析手法を確立した。本研究で開発された2つの手法は、中東地域の古環境復元のみならず、世界中の地域を対象としたサンゴ骨格を用いた古環境復元への応用が期待される。