| Project/Area Number |
09480133
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境保全
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| Research Institution | Okayama University |
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Principal Investigator |
MAITANI Toshihiko Okayama Univ., Research Institute for Bioresources, Prof., 資源生物科学研究所, 教授 (00025412)
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| Co-Investigator(Kenkyū-buntansha) |
KONNO Haruyoshi Okayama Univ., Research Institute for Bioresources, Assoc.Prof., 資源生物科学研究所, 助教授 (10108178)
TANAKAMARU Shigemi Okayama Univ., Research Institute for Bioresources, Assoc.Prof., 資源生物科学研究所, 助教授 (10116478)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥9,500,000 (Direct Cost: ¥9,500,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥8,400,000 (Direct Cost: ¥8,400,000)
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| Keywords | Rasyomon doline / cold air flow / stable thermal layer / water vapor transport / high concentration of CO_2 / photosynthesis and transpiration / shade plant / plant protection / 陰生植物 / 微気象観測 / 植物の光合成蒸散反応 / コケ |
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| Research Abstract |
Micrometeorological factors( such as air temperature, humidity, air flow, and photosynthesis available radiation) and physiological factors of plants ( such as photosynthesis and transpiration rates) were measured in Rasyomon doline. At the lowest point in the doline, erosion created a weak breathing, blowing cavetunnel, draining a cold air in warmer seasons. The bottom in the depression was characterized by daytime summer temperatures below about 15ﾟC.Throughout warm seasons, very stable thermal layer was formed in the doline and it maintained a perhumid climate, which was a favorite environment to mosses.
To clarify how the air flow from the cave relates to the drying in the doline, we artificially closed the narrowest section of the cave 2 times in the summer of 1997. Air temperature and soil temperature were higher by 3-4ﾟC in the closed period than in the opened period of cave. However, water, vapor increased by 4-5 hPa in the closed period than that in the opened period. The CO_2 concentration were about 700 ppm in the opened period and increased high levels near 1000 ppm in the closed period of cave. These results demonstrate quantitatively that the strengthned air with a cool but dehumified air is closely related to drying of the doline. The closure of cave also induced a significant rise of CO_2 concentration at the bottom of the doline, which is a favorite environment for mosses to grow. Considering these results, we are now planning to reduce an air flow through the cave to prevent from drying of caveand to renew the moss forest. Most of plants growing at the bottom of the doline had physiological charactersitics of shade plant, adopting to the specific environment of doline.
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