2021 Fiscal Year Final Research Report
Study of the response of deep-sea organisms to rapid warming: analysis of benthic foraminifera in the Bering Sea.
| Project/Area Number |
19K04056
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 17050:Biogeosciences-related
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| Research Institution | Kobe University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 底生有孔虫 / ベーリング海 / 最終氷期 / 溶存酸素極少層 |
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| Outline of Final Research Achievements |
Benthic foraminifera had been studied in the Bering Sea, located in the northern North Pacific Ocean. Especially a response of benthic foraminiferal assemblages to climate change was investigated over the past 60,000 years from marine sediments. The subarctic North Pacific climate from 60,000 to 20,000 years ago was cold, unlike the present warm environment, and was the last glacial period when huge ice sheets grew and collapsed repeatedly in North America. Benthic foraminifera has inhabited the seafloor around a depth of 1000m, where they were under the influence of cold mid-depth water with a temperature of 4°C or lower. Although this depth is currently covered with a minimum dissolved oxygen layer, it is clear that oxygen-depletion events during the last glacial period were repeated with interstadial events on a scale of several millennia.
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| Free Research Field |
古生物学
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| Academic Significance and Societal Importance of the Research Achievements |
ベーリング海の底生有孔虫化石群集の研究により，最終氷期の現在よりも寒冷な時代には北部北太平洋の水深１０００ｍの深海底において数百年スケールで溶存酸素濃度が著しく変動しており，現在の酸素濃度よりもさらに低下する酸欠イベントが繰り返し発生していたことが明らかになった．その変動は，北極圏の大気変動に何らかの関連性を示唆しており，北極圏の大気変動と北太平洋間の気候のテレコネクションのメカニズム解明に向けた基礎研究として意義のある研究成果である．さらに，北海道東方沖の海底コアの研究では，最終退氷期の急激な温暖化と共に親潮水域の中層水域でも貧酸素水塊が浅い水深にまで拡大したことを明らかにした．
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