1999 Fiscal Year Final Research Report Summary
The phase transition of ecosystem structure in the upper ocean
| Project/Area Number |
10480125
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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 |
Environmental dynamic analysis
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NAGATA Toshi The University of Tokyo, Ocean Research Inst., Associate professor, 海洋研究所, 助教授 (40183892)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yasunori Tokyo Metropolitan Univ., Fac. of Science, Professor, 理学部, 教授 (20112477)
HIGASHI Masahiko Kyoto university, Center for Ecological Res., professor, 生態学研究センター, 教授 (40183917)
KOGURE Kazuhiro The University of Tokyo, Ocean Research Inst., Associate professor, 海洋研究所, 助教授 (10161895)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Ocean / Dissolved organic matter / Carbon cycle / Food web / Microorganisms / Ecological model / Amino acids / Oceanic ecosystem |
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| Research Abstract |
(1) Vertical and horizontal distributions of bacterial abundance, production and ectoenzyme activities (amino peptidase and beta-glucosidase), as well as amino acid concentrations were determined in the subarctic Pacific. These microbial parameters exhibited notable east-west gradient, with generally high values in the west and low values in the east. The data suggest a large-scale regime shift of ecosystem structure in the investigated region, which appeared to be related to plankton community structure and biogeochemical variations.
(2) In order to examine regulation mechanisms of organic matter - bacteria systems in marine environments, decomposition rates of polymeric carbohydrate was determined by using radio tracer techniques. Results suggest that organic matter complexation plays an important role in preservation of organic matter in marine systems.
(3) Organic matter-microbial dyanamics in oceanic environments was modeled by using parameters derived from a oceanic biogeochemical data base. The analysis revealed that network virtual amplification is common in oceanic ecosystems because of intensive recylcing of organic matter withing the system.
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Research Products
(8 results)
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[Publications] Fukuda, R., Sohrin, Y., Saotome, N., Fukuda, H., Nagata, T. and Koike, I.: "East-west gradient in ectoenzyme activities in the subarctic Pacific : Possible regulation by zinc."Limnology and Oceanography. (In press). (2000)
Description
「研究成果報告書概要(欧文)」より
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