| Project/Area Number |
18K03818
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 17050:Biogeosciences-related
|
|---|
| Research Institution | National Museum of Nature and Science, Tokyo (2019-2022)
Akita University (2018) |
|---|
Principal Investigator |
Yamasaki chieko 独立行政法人国立科学博物館, 地学研究部, 協力研究員 (60597186)
|
|---|
| Project Period (FY) |
2018-04-01 – 2023-03-31
|
| Project Status |
Completed (Fiscal Year 2022)
|
| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2021: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2019: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000)
Fiscal Year 2018: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
|
|---|
| Keywords | 珪藻化石 / 白亜紀 / 古海洋 / 進化 / 生態 / 北海道 / 珪藻 / 北西太平洋 / 適応放散 |
|---|
| Outline of Final Research Achievements |
Diatoms have flourished through the almost entire Cenozoic hydrosphere as one of the most important eukaryotic primary producers, so their evolutionary history is worthy of understanding. Yet their early evolution during the Cretaceous, particularly the mid-Cretaceous interval (Cenomanian to Turonian age) is unclear owing to extremely few fossil records. I presented new fossil records of Cenomanian and Turonian opaline diatoms in carbonate concretions hosting ammonites from Hokkaido, Northwestern Pacific Ocean. The Cenomanian diatoms are basically similar to the late Early Cretaceous flora, but somewhat transitional in associating with a few taxa typical of the late Late Cretaceous time. By contrast, most of the Turonian taxa are found to be typical of the late Late Cretaceous. I thus succeeded to confirm the mid-Cretaceous diatoms to have drastically overturned in the Cenomanian-to-Turonian interval, when the extreme paleoceanographic crisis known as the Ocean Anoxic Event 2 onset.
|
| Academic Significance and Societal Importance of the Research Achievements |
こんにちの水圏において生態学的に最も成功した一次生産者である珪藻にとって，中生代とは分類群としての成立期にあたり，この時代の化石記録を検討することは珪藻の進化史を理解する上で極めて重要であるが，中生代（事実上は白亜紀）特に，白亜紀の中期（約1億～8980万年前）については絶望視されてきた．
白亜紀の中期に予想される超温暖化や海洋無酸素事件は，地球史上最も苛烈な古海洋事件の1つである．こうした例外的な環境変動と低次生態系との相互作用（物質循環や進化的放散）の実態を指示する直接証拠である珪藻の化石記録が得られたことは極めて意義深いといえる．
|
