| Project/Area Number |
26550011
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Kumamoto University |
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Principal Investigator |
MATSUDA HIROKI 熊本大学, 大学院先端科学研究部(理), 教授 (80274687)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Project Status |
Completed (Fiscal Year 2016)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 鍾乳石 / 炭素・酸素同位体比 / 地下水涵養 / 植生変遷 / 炭酸塩続成作用 / 南大東島 |
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| Outline of Final Research Achievements |
To clarify the groundwater (GW) percolation system and the growth mechanism of stalagmites under different vegetation covers, the measurements of the soil and cave environments and water chemistry of the drip waters (DW) were carried out in Minami-Daito Island.
Saturation index for calcite (SIc) in DW are positive and are higher in dry season and under sugarcane field than under forests. The amounts of DW are relatively constant under forests, while those change responding to rainfall under sugarcane field. From the results, the growth mechanism of stalagmites is as follows; At first, GW has high CO2 due to percolating through soil with high CO2, and dissolves underlying carbonate rocks. With GW flowing downward, degassing of the dissolved CO2 with evaporation leads to increase in the SIc. Especially, the SIc become higher by intense evaporation in dry season, which is more active in sugarcane field. Consequently, the growth rate of stalagmite under sugarcane field is higher.
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