| Project/Area Number |
10460082
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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 |
General fisheries
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
HINO Akinori The Univ.of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (90012012)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Shigeru The Univ.of Tokyo, Graduate School of Agricultural and Life Sciences, Assistant, 大学院・農学生命科学研究科, 助手 (50270898)
OKAMOTO Ken The Univ.of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Prof., 大学院・農学生命科学研究科, 助教授 (20160715)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥9,000,000 (Direct Cost: ¥9,000,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1999: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1998: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | Stable-isotope ratio / Oyster / Hamana-ko Bay / Production mechanism / Detritus / Food habit / Fluctuation through metabolism / Mesocosm / 閉鎖性内湾 / 二枚貝 / 餌料懸濁物 / 懸濁物 / 地理的変化 / 季節的変化 |
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| Research Abstract |
Bivalves have many obscurity In their production ecology, though they are majour fishiery resorces of a closed bay. We analysed production mechanism of the oyster Crassostrea gigas in Hamana-ko bay using natural abundance ratios of C and N stable isotopes, in addition to the discussion on the prospects and problems of the technic.
In a mouth area of Hamana-ko bay, particulated organic matter (POM) was mainly composed of detritus, and l3δC was lower than -21. In inner areas, both 13δC and 15δN of a ganadal-digestional part (GD) of the oyster changed synchronously with those of POM when algal bloom was observed, but the satates of both POM and 13δC were the same as in a mouth area when any particular blooming didn't occur. We made clear that oyster production in the lake depends on detrirus fundamentally and additional growth are supported by primary production.
From culturing experiments on algal POM both in microcosms and mesocosms, stable isotope ratios of POM were revealed to be affected either with nutritiona1 type, photo-synthesis activity or growth phase of algae, in addition to algal species.
Another culturing experiments on the effects of metabolic states of the oyster showed that either maturation, increasing temperature or growth makes the turnover of isotopes dull.
In conclusion, quantitative investigations on detritus would be more inportant than on primary production which was thought to be main food source of the oyster. And, stable isotope ratios of natural 13δC and 15δN will be "effective tools" after fluctuation factors pointed out in culturing experiments on algal POM or the oyster.
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