| Project/Area Number |
17K15342
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Rural environmental engineering/Planning
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| Research Institution | Iwate University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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| Keywords | 閉鎖性水域 / アオコ / 藍藻類 / 水鳥 / 水質予測モデル / 水温成層 / 低次生態系モデル / 鉛直移動 / 栄養塩類 / 現地観測 / 群体 / 移動速度 / 水圏現象 / 水工水理学 |
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| Outline of Final Research Achievements |
In this study, short-term behavior of blue-green algae in a shallow water body, like an agricultural reservoir, was studied. Focusing on hydraulic factors in particular, we measured the water temperature stratification during the daytime and the mixing during the nighttime in the reservoir. In addition, we conducted a comparative study on the difference in the diurnal behavior between blue-green algae and other algae. As the result of the field observation on the behavior of blue-green algae in the reservoir with strong water temperature stratification, most of the algae were concentrated under the mixed layer, and from that part, only a group of blue-green algae diverged between this layer and the water surface. The floating speed was negatively correlated with buoyancy frequency, showing the strength of the water temperature stratification. In addition, the floating speed of the blue-green algae became larger than the past laboratory experiment results.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究ではアオコの発生する閉鎖性水域内の栄養塩動態に関する検討を行うことを目的として、とくに水鳥が多数飛来する閉鎖性水域を対象に，農業用貯水池の多面的機能を総合的に発揮する管理手法を検討した。水鳥の飛来は景観形成効果に寄与する一方で水質悪化という負の影響も懸念される。そこで、アオコの発生する夏季を対象に短期連続観測を行い，水温成層状態の形成・消失過程と，藍藻類の浮上・沈降過程の関係について検討を行うとともに水域内流動モデルと組み合わせることで，アオコ発生制御を目的とした夏季における密度成層場の藍藻類の挙動予測モデルを構築することは適切な水質管理を検討する上で重要な課題である。
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