1993 Fiscal Year Final Research Report Summary
Discharge and chemistry of stream water in northern part of Hokkaido
| Project/Area Number |
04454078
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
林学
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| Research Institution | Hokkaido University |
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Principal Investigator |
FUJIWARA Koichiro Hokkaido Univ.Exp.Forests, Professor, 農学部・附属演習林, 教授 (00001503)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANO Shigeru Hokkaido Univ.Exp.Forests, Instractor, 農学部・附属演習林, 助手 (50217791)
SATOH Fuyuki Hokkaido Univ.Exp.Forests, Instractor, 農学部・附属演習林, 助手 (20187230)
GOTO Yoshihiko Hokkaido Univ.Exp.Forests, Instractor, 農学部・附属演習林, 助手 (20221252)
SASA Kaichiro Hokkaido Univ.Exp.Forests, Asistant Prof., 農学部・附属演習林, 助教授 (70125318)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Forest hydorology / Discharge in winter / Discharge charactor of drainage basin / Surpentine basin / Aacid precipitation / Dissolved organic materials / Plant index / Eecology of freshwater fish |
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| Research Abstract |
This research was carried out in the northermost part of Hokkaido, Japan, a cold and snowy region during winter.
1) The pH of precipitation at Toikanbetsu station of Teshio Experimental Forest, Hokkaido University, was in the range of 4.00-6.80. The mean value of snowfall pH was 4.71 and that of rainfall was 5.00, respectively. At this station, the chemical composition of snowfall was affected by sea salts and the influence of SO_4 constituting from artificial origins was also obsrved from several snowfall samples.
2) The winter discharge at 7 small basin became near constant, 0.3-1.8mm/day, from February to Mid-march and cleary depended on the geological charactors of the basin.
3) The pHs of streamwater in the Teshio Experimental Forest during drought water-level in summer were 5.4-6.2 at the basins consisting of Tertiary mudstone and about 8.2 at the basis consisting of weathered serpentine materials.
4) The content of dissolved organic materials in the streamwater of this Forest was very low during drought water-level in summer season. At rain event, however, many dissolved organic materials eloded out from the basin and the concentration of organic materials was higher at the basins with forest covers compared to that with no forest.
5) Forests at windy and cold region not only prevent ground freezing by preserving snow cover, but also have the effect on scuring water resources during mid-winter.
6) When white-spoted charr (Salvelinus leucomaenis) and Dolly Varden (S.malma) cohabit the same reaches, distinct resosurce partitioning occurs between the two species. In contrast to the allopatric populations where each species primarily feeds on terrestrial insects drifting in the stream, the sympatric Dolly Varden shifts its primary diets to the benthic invertbrates. The proportions on these two foragers are changed depending on stream discharge as carrier of drifting food.
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