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1997 Fiscal Year Final Research Report Summary

Dynamics of organic colloidal particles in aquatic microbial food webs

Research Project

Project/Area Number 07404044
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field 生態
Research InstitutionOcean Research Institute, University of Tokyo

Principal Investigator

KOIKE Isao  Ocean Reseach Institute, Univ.of Tokyo, Professor, 海洋研究所, 教授 (30107453)

Co-Investigator(Kenkyū-buntansha) OGAWA Hiroshi  ORI.Univ.of Tokyo, Reseach Associate, 海洋研究所, 助手 (50260518)
KOGURE Kazuhiro  ORI.Univ.of Tokyo, Associate Professor, 海洋研究所, 助教授 (10161895)
Project Period (FY) 1995 – 1997
Keywordscolloid particles / microbial food webs / aquatic ecosystem / dissolved organic matter / suspended organic matter / bacterial population / heterotrophic nanoflagellates / organic detritus
Research Abstract

The aim of this research is the mechanistic understanding of organic detritus dynamics in marine environments through focusing on the characterization of submicron sized detritus and their production and degradation by microbial food webs such as bacterioplankton and microzooplankton. The finding of" submicron particles " as the predominant forms of non-living organic detritus of bacterial size range in 1990 by our group stimulated the studies on the role of those organic detritus, which are in the boundary between dissolved and suspended forms of detritus in the upper ocean. Before this research, however, a few knowledge has been obtained in the open ocean, such as size distribution and some physico-chemical properties, partially because of the limit of available techniques. Through the interdisciplinary approaches of this study, following new findings were obtained. 1. The size distribution of submicron organic detritus varied significantly with the biological productivity of the env … More ironments, and the production of 0.6-0.8 mum sized detritus dominated under the high biological productivity. 2. Estimated carbon contents of organic detritus of submicron size range gave much higher value compared to the carbon contents of living particles of this size, i.e., bacteria, indicating that organic detritus of submicron size are also predominant form of organic carbon stock in the upper ocean. 3. Using a high sensitivity CCD camera system, amorphous and aggregated nature of those organic detrital particles were confirmed, This finding was consistent with the previous physical characterization of the particles. 4. As the major production process of the submicron detritus, fecal pellets formation of microflagellates through the grazing activities were strongly suggested, and also further aggregation of those submicron detritus to larger sized aggregates were indicated, The above findings were the important contribution to mechanistic understanding of complicated dynamics of marine organic detritus, such as marine snow, suspended-, colloidal- and dissolved-organic forms, and their association with marine food webs. Less

  • Research Products

    (10 results)

All Other

All Publications (10 results)

  • [Publications] HARA,S.,and I.KOIKE: "Dynamics of organic marine aggregates nanometer colloids to marine snow-In Biogeochemistry of Marine Organic Matter (eds.N.Handa et al.)" Tera Academic Press,Tokyo. in press.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] SHIBATA,A.,K.KOGURE,I.KOIKE,and K.OHWADA: "Formation of submicron colloidal particles from marine bacteria by viral infection" Mar.Ecol.Progr.Ser.in press.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] KOIKE,I.,and T.NAGATA: "High potential activity of extracellular alkaline phosphatase in the deep waters of the central Pacific." Deep-Sea Res.in press.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] NAGATA,T.,R.FUKUDA,I.KOIKE,K.KOGURE,and D.L.KIRCHMAN: "Degradation of bacteria of membtane and soluble protein in seawater." Aquat.Microb.Ecol.in press.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] YAMAZAKI,A.,H.FUKUDA,R.FUKUDA,T.MIYAJIMA,T.NAGATA,H.OGAWA,and I.KOIKE: "Summicrometer particles in northwest Pacific coast environments:Abundances,size distribution and biological origins." Limnol.Oceanogr.in press.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] SHIBATA,A., K.KOGURE,I.KOIKE,and K.OHWADA: "Formation of submicron colloidal particles from marine bacteria by viral infection." Mar.Ecol.Progr.Ser.(in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] KOIKE,I., and T.NAGATA: "High potential activity of extracellular alkaline phosphatase in the deep waters of the central Pacific." Deep-Sea Res.(in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] NAGATA,T., R.FUKUDA,I.KOIKE,K.KOGURE,and D.L.KIRCHMAN: "Degradation of bacteria of membrane and soluble protein in seawater." Aquat.Microb.Ecol.(in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] YAMAZAKI,A., H.FUKUDA,R.FUKUDA,T.MIYAJIMA,T.NAGATA,H.OGAWA,and I.KOIKE: "Summicrometer particles in northwest Pacific coast environments : Abundances, size distribution and biological origins." Limnol.Oceanogr.(in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] HARA,S., and I.KOIKE: Dynamics of organic marine aggregates nanometer colloids to marine snow In Biogeochemistry of Marine Organic Matter (eds.N.Handa et al.).Tera Academic Press, Tokyo (in press).,

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-12-08  

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