| Project/Area Number |
04650506
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
都市工学・衛生工学
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| Research Institution | National Institute for Environmental Studies (NIES) |
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Principal Investigator |
FUKUSHIMA Takehiko NIES, Regional Environment Division, Head of Lake Conservation Research Team, 地域環境研究グループ, 総合研究官 (90124354)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Takanobu NIES, Water and Soil Environment Division, Researcher, 水上壌圏環境部, 研究員 (00184755)
AIZAKI Morihiro NIES, Water and Soil Environment Division, Principal Researcher, 水上壌圏環境部, 上席研究官 (20109911)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1992: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Phosphorus / Turnover / Bioactivity / Radioisotope / River / Lake / バイオアッセイ / 河川 |
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| Research Abstract |
The P uptake rates and the ratios after the equilibrium were measured radioisotropically for the samples obtained in L.Kasumigaura (Japan), L.Lucerne, L.Greifen (Switzerland), and their influent rivers. The determination of ambient available P concentrations were also performed by the Riger assay approach, in which the ^<32>P uptake rates were compared for the samples added different ^<32>PO_4-P concentrations as well as ^<32>PO_4-P.The results are as follows ;
(1) The P turnover times of the river samples ranged from 1 hour to 100 hours, which were considerably longer than those of the samples obtained in L.Lucerne (oligotrophic lake) and the epilimnions of L.Kasumigaura and L.Greifen (eutrophic lakes). The less polluted river had longer turnover time, which indicated the relatively high supply rate of P for microorganisms in water.
(2) The higher ratios fo particulate to dissolved components at equilibrium were obtained in more polluted rivers ; then this ratio mainly reflected the biomass and bioactivity of the microorganisms.
(3) The ambient available P concentrations ranged from 0.01 ug/l to 0.1 ug/l, which were less than one tenth of soluble reactive phosphorus determined colorimetrically.
(4) The uptake rates of ^<14>C-glucose were nearly proportional to those of ^<32>PO_4-P.This fact suggests that the P uptake is possibly attributable to heterotrophic activities.
In addition, the change in the periphyton biomass was observed and simulated in Hinuma River.
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