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2006 Fiscal Year Final Research Report Summary

Observational research for iron, biological productivity, and carbon cycle in the subarctic northwestern Pacific

Research Project

Project/Area Number 16310019
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Environmental dynamic analysis
Research InstitutionFisheries Research Agency

Principal Investigator

ONO Tsuneo  Fisheries Research Agency, Subarctic Fisheries Oceanography Division Hokkaido National Fisheries Research Institute, Chief Scientist (40371786)

Co-Investigator(Kenkyū-buntansha) KASAI Hiromi  Fisheries Research Agency, Subarctic Fisheries Oceanography Division, Hokkaido National Fisheries Research Institute, Scientist (60371788)
NISHIOKA Jun  Hokkaido University, Pan-Okhotsk research Center, Institute of Low Temperature Science, Assistant Professor (90371533)
WATANABE Yutaka  Hokkaido University, Graduate School of Environmental Earth Science, Assistant Professor (90333640)
YOSHIMURA Takeshi  Fisheries Research Agency, Central Research Institute of Electric Power industry, Scientist (20371536)
Project Period (FY) 2004 – 2006
Keywordsiron / nutrient / Oyashio / primary production
Research Abstract

2-D iron distribution in the subarctic northwestern Pacific was investigated repeatedly from 2003 to 2006 with high spacio-temporal resolution equally to major nutrients. Seasonal and interannual variations of iron observed in the Oyashio domain brought us the following information :
1] Monthly-mean concentration of dissolved iron (DFe) in the Oyashio mixed layer varies in parallel with nitrate, with its maximum anteceding the Kosa season. Ratio of DFe to the nitrate is fairly constant throughout the year (ΔDFe/ΔN=27×10^<-6>[mol/mol]), and this ratio resembles those of North Pacific intermediate water (NPIW). Based on these observation results and a simple model calculation, it is concluded that the seasonal variation of Dfe in the Oyashio mixed layer is mainly governed by spring-summer biological consumption and winter recirculation from the NPIW. Iron input from the dust deposition is implied to have small effect to the mixed-layer iron cycle, although small-scale high iron patch might sometimes be generated by local iron deposition.
2] More than half of the DFe data observed in Oyashio mixed layer at the bloom-termination period shows roughly constant value of 0.25 nM, implying that the bloom-forming diatoms incur significant iron limitation below this iron level. In spring, iron reaches this lower-limit faster than nitrate, forming iron-limited ecosystem conditions at the end of spring bloom. In summer, however, the ultimate depletion of mixed layer nitrate occurs faster than that of DFe at July, forming nitrate-limited ecosystem in the summer Oyashio domain.

  • Research Products

    (9 results)

All 2007 2006 2005 Other

All Journal Article (8 results) Book (1 results)

  • [Journal Article] Iron supply to the western subarctic Pacific:Importance of iron export from the Sea of Okhotsk2007

    • Author(s)
      Jun Nishioka
    • Journal Title

      Journal of Geophysical Research 112

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] 根室海峡における春季および秋季の水質変化過程2007

    • Author(s)
      小熊 幸子
    • Journal Title

      海の研究 16

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] 北太平洋における鉄の存在状態と鉄が生物生産におよぼす影響に関する研究2006

    • Author(s)
      西岡 純
    • Journal Title

      海の研究 15

      Pages: 19-36

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] On the chemical form of iron and its effect to the biological productivity in the North Pacific Ocean.2006

    • Author(s)
      Nishioka, J.(Japanese with English abstract)
    • Journal Title

      Umi-no Kenkyu 15

      Pages: 19-36

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Seasonal and interannual variation of DIC in the Oyashio mixed layer:A climatological view2005

    • Author(s)
      Tsuneo Ono
    • Journal Title

      Journal of Oceanography 61

      Pages: 1075-1088

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Sasaki, Seasonal and interannual variation of DIC in the Oyashio mixed layer : A climatological view.2005

    • Author(s)
      Ono, T., H. Kasai, T. Midorikawa, Y. Takatani, K. Saito, M. Ishii, Y. W. Watanabe, K.
    • Journal Title

      J. Oceanogr. 61

      Pages: 1075-1088

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Iron supply to the western subarctic Pacific : Importance of iron export from the Sea of Okhotsk.

    • Author(s)
      Nishioka, J., T. Ono, H. Saito, T. Nakatsuka, S. Takeda, T. Yoshimura, K. Suzuki, K. Kuma, S. Nakabayashi, D. Tsumune, H. Mitsudera, W. K. Johnson and A. Tsuda
    • Journal Title

      J. Geophys. Res. (in press)

      Pages: 112

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] processes of watermass alternations in the Nemuro Straight during spring and Autumun.

    • Author(s)
      Oguma, S., Y. Kawasaki, and T. Azumaya
    • Journal Title

      Umi-no Kenkyu(Japanese with English abstract) 16(in press)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Book] 月刊海洋号外432006

    • Author(s)
      小熊 幸子
    • Total Pages
      82-91
    • Publisher
      安定同位体を用いた沿岸親潮域の水塊分布変動の把握
    • Description
      「研究成果報告書概要(和文)」より

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Published: 2010-02-04   Modified: 2021-12-06  

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