| Project/Area Number |
11305036
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | Osaka University |
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Principal Investigator |
NAKATSUJI Keiji Graduate School of Eng., Osaka University, Professor, 大学院・工学研究科, 教授 (10029324)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Tateki Kyoto Univ., Graduate School of Agriculture, Associate Prof., 大学院・農学研究科, 助教授 (30243075)
KAWASAKI Koji Graduate School of Eng., Osaka University, Research Assoc., 大学院・工学研究科, 助手 (20304024)
NISHIDA Shuzo Graduate School of Eng., Osaka University, Associate Prof., 大学院・工学研究科, 助教授 (40172663)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥32,980,000 (Direct Cost: ¥31,600,000、Indirect Cost: ¥1,380,000)
Fiscal Year 2001: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
Fiscal Year 2000: ¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1999: ¥20,100,000 (Direct Cost: ¥20,100,000)
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| Keywords | estuary / water quality / bottom sediment / release / nutrients / shallow water sediment / water quality model / ecosystem / 水質・底質予測モデル / 溶出機構 / 底泥 / 溶出過程 / 底泥モデル / 水質予測 |
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| Research Abstract |
The purpose of the present study is to investigate the behaviors of nutrients inflowed from land area, and the interactions between sediments and water quality in semi-enclosed sea area. Moreover, a water quality model is developed based on the field survey results, which takes sediment-water interactions at sea bottom into account.
1) Release of nutrients in shallow sea sediment : The sea sediments properties at sea bottom were examined by conducting the field survey in Osaka Bay. The laboratory experiments revealed the characteristics of the release rate of nitrogen and phosphorus, the denitrification rate, and so on.
2) Behaviors of inflow sediment from land area : The stable isotopes of nitrogen and carbon in the sediment were measured in the Yamato River in order to comprehend the behaviors of inflow sediment from land. As a result, it is considered that most of inflow sediments are settled and deposited around the river mouth of Yamato River.
3) Relationship between estimated inflow nutrient loads and measured water quality : The inflow nutrient loads from 1921 to 1995 were estimated with the ratio unit method. The effects of nutrient loads from land on the water quality in Osaka Bay were examined based on socio-economic data such as population, livestock, and industrial product.
4) Development of water quality, model with sediment-water interactions at sea bottom : The developed water quality model can deal with sediment-water interactions in terms of sedimentation of organic detritus from the pelagic zone into the benthic zone and release of nutrients in the reverse direction. The validity tests of the model for the principal parameters reveal that both nitrogen and phosphorous are sensitive to settling velocity of nutrients from sea.
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