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Effects of fluvial nutrients and its historical change on lower trophic level productivity in subarctic coastal ecosystem

Research Project

Project/Area Number 18510002
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Environmental dynamic analysis
Research InstitutionHokkaido University

Principal Investigator

KUDO Isao  Hokkaido University, Faculty of Fisheries Sciences, Associate Professor (00195455)

Co-Investigator(Kenkyū-buntansha) MONTANI Shigeru  Hokkaido University, Faculty of Fish. Sciences, Professor (30136288)
Project Period (FY) 2006 – 2007
Project Status Completed (Fiscal Year 2007)
Budget Amount *help
¥4,150,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥450,000)
Fiscal Year 2007: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
Keywordsprimary production / nutrients / chlorophylla / Ishikari Bay / Ishikari River / bio-element cycle / biogenic silicon / land-ocean interaction / 植物ブランクトン / 物質環境 / 植物プランクトン
Research Abstract

This study was conducted in oligotrophic coastal bay, which is located in subarctic ocean where productivity is generally high. This is due to strong influence of Tsushima warm current, subtropical ocean current. The objectives of this study was to elucidate the effect of fluvial nutrient fluxes and its composition on the lower trophic ecosystems in Ishikari Bay, oligotrophic coastal bay. Chemical analyses on sediment cores were conducted to understand the historical changes in primary productivity and fluvial nutrient fluxes. The results of chemical analyses of sediment cores collected in the river plume suggested as follows.
1) High organic carbon contents and high C:N ratios were found in 1970's layer, suggesting high loadings of peat soil due to development of farming ground and frequent flood in this period.
2) Biogenic silica contents in the sediment core near the river mouse showed the increasing tendency toward present from 30 to 40 years ago. Biogenic silica is a good indicator of diatom production because only diatoms produce biogenic silica as their frustules. Diatoms are dominant phytoplankters where primary productivity is high. Therefore, high content of biogenic silica indicates diatom production (primary productivity) was high. The reason for the increasing trend of primary productivity seemed the decreasing load of suspended solids from the Ishikari River due to the construction of embankment or the increasing flux of nutrients from the Ishikari River due to the urbanization and over-use of fertilizers.

Report

(3 results)
  • 2007 Annual Research Report   Final Research Report Summary
  • 2006 Annual Research Report
  • Research Products

    (13 results)

All 2009 2008 2007 2006

All Journal Article (2 results) (of which Peer Reviewed: 1 results) Presentation (11 results)

  • [Journal Article] Seasonal change of riverine nutrients and distribution of chlorophyll a in Ishikari Bay, subarctic oligotrophic coastal environment of Japan.2009

    • Author(s)
      Agboola, I, Yoshi, S., Kudo, I.
    • Journal Title

      La mer (印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Seasonal change of riverine nutrients and distribution of chlorophyll a in Ishikari Bay, subarctic oligotrophic coastal environment of Japan.2009

    • Author(s)
      Agboola, I., Yoshi, S., Kudo, I.
    • Journal Title

      La mer (in press)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Dynamics of pelagic variables in two contrasting coastal systems in the western Hokkaido coast off Otaru.2008

    • Author(s)
      Agboola, J. I., Kudo, I.
    • Organizer
      Eighth EMECS (Environmental Management of Enclosed Coastal Seas) Conference
    • Place of Presentation
      Shanghai, China
    • Year and Date
      2008-11-29
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Dynamics of pelagic variables in two contrasting coastal systems in the western Hokkaido coast off Otaru2008

    • Author(s)
      Agboola, J. I., Kudo, I.
    • Organizer
      Eighth EMECS (Environmental Management of Enclosed Coastal Seas) Conference 2008
    • Place of Presentation
      Shanghai, China
    • Year and Date
      2008-11-29
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Spatio-temporal analyses of nutrients and phytoplankton biomass in sub-arctic coastal environment of Japan2008

    • Author(s)
      Agboola, J. I., Kudo, I.
    • Organizer
      American Society of Limnology and Oceanography
    • Place of Presentation
      St. John's, Canada
    • Year and Date
      2008-06-10
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Spatio-temporal analyses of nutrients and phytoplankton biomass in sub-arctic coastal environment of Japan2008

    • Author(s)
      Agboola, J. I., Kudo, I.
    • Organizer
      American Society of Limnology and Oceanography, 2008 Summer Meeting
    • Place of Presentation
      St. John's, Canada
    • Year and Date
      2008-06-10
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 石狩湾堆積物中における生物起源ケイ素を指標とした基礎生産変動2007

    • Author(s)
      日高 康晴・吉 俊輔・工藤 勲
    • Organizer
      日本海洋学会
    • Place of Presentation
      琉球大学工学部
    • Year and Date
      2007-09-28
    • Related Report
      2007 Annual Research Report
  • [Presentation] 石狩湾堆積物中における生物起源ケイ素を指標とした基礎生産変動2007

    • Author(s)
      日高康晴, 吉俊輔, 工藤勲
    • Organizer
      日本海洋学会
    • Place of Presentation
      琉球大学、那覇市
    • Year and Date
      2007-09-23
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Variation of primary productivity reproduced from biogenic silica in the sediment core in Ishikari Bay2007

    • Author(s)
      Hidaka, Y., Yoshi, S., Kudo, I.
    • Organizer
      Oceanographic Society of Japan, Fall meeting
    • Place of Presentation
      Ryukyu University, Naha
    • Year and Date
      2007-09-23
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] ウイルス溶菌が従属栄養細菌群集の死亡速度に及ぼす影響2006

    • Author(s)
      内宮万里央, 吉俊輔, 工藤勲
    • Organizer
      日本海洋学会
    • Place of Presentation
      名古屋大学、名古屋市
    • Year and Date
      2006-09-26
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Effect of virus lysis on mortality of heterotrophic bacteria.2006

    • Organizer
      Oceanographic Society of Japan, Fall meeting
    • Place of Presentation
      Nagoya University, Nagoya
    • Year and Date
      2006-09-26
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 石狩湾における石狩川ブルームの分布特徴と基礎生産に及ぼす影響2006

    • Author(s)
      吉俊輔, 工藤勲
    • Organizer
      日本海洋学会
    • Place of Presentation
      名古屋大学、名古屋市
    • Year and Date
      2006-09-25
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Distribution of Ishikari River plume water and its effect on primary productivity in Ishikari Bay2006

    • Organizer
      Oceanographic Society of Japan, Fall meeting
    • Place of Presentation
      Nagoya University, Nagoya
    • Year and Date
      2006-09-25
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary

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Published: 2006-04-01   Modified: 2016-04-21  

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