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Development of Paleoceanographic Proxy for Sea Ice and Analysis of Historical Variation in Okhotsk Sea Ice.

Research Project

Project/Area Number 12440151
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 地球化学
Research InstitutionHOKKAIDO UNIVERSITY

Principal Investigator

NAKATSUKA Takeshi  Hokkaido Univ., Inst. Low Temp. Sci., Asso. Prof., 低温科学研究所, 助教授 (60242880)

Co-Investigator(Kenkyū-buntansha) WAKATSUCHI Masaaki  Hokkaido Univ., Inst. Low Temp. Sci., Prof., 低温科学研究所, 教授 (60002101)
SAKAMOTO Tatsuhiko  Hokkaido Univ., Grad. School of Sci., Inst., 大学院・理学研究科, 助手 (90271709)
Project Period (FY) 2000 – 2001
Project Status Completed (Fiscal Year 2001)
Budget Amount *help
¥15,000,000 (Direct Cost: ¥15,000,000)
Fiscal Year 2001: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2000: ¥11,900,000 (Direct Cost: ¥11,900,000)
KeywordsSea Ice / Sea of Okhotsk / Paleoceanography / IRD / Biomarker / Sinking Particle / Sediment Core / 海氷 / 古海洋 / 温暖化 / セジメントトラップ / 陸起源砕屑粒子
Research Abstract

Sea ice influences climate system on Earth through several ways such as increasing the surface albedo, interfering air-sea heat exchanges and driving thermo-haline circulations in ocean. The purpose of this study is to investigate historical variation in the sea ice of the Sea of Okhotsk, which is now located at lowest latitude in the world. Firstly, we had developed paleoceanographic proxies for Okhotsk sea ice, and applied them to sediment cores. We attempted to utilize two kinds of proxies. One was a group of characteristic biomarkers in diatom (main species of ice algae), Highly Branched Isoprenoids (HBI), and the other was terrigenous clastic materials transported by sea ice, Ice Rafted Debris (IRD). Unfortunately, we could not apply HBI for the reconstruction of Okhotsk sea ice because HBI was not found in sediments of the Sea of Okhotsk. However, comparison between time-series data of sinking particles collected by sediment traps and satellite observations of seasonal sea ice distribution could demonstrate that the IRD actually drops only during the period of sea ice melting, and IRD could be applied to reconstruct past changes in production and distribution of sea ice in the Sea of Okhotsk. We applied the IRD and many other proxies for paleoceanographic environments to sediment cores in the Sea of Okhotsk, and have obtained following results. 1) In glacial periods, sea ice expanded frequently according to global cooling events known as Heinrich Events. 2) During a warm period of early and middle Holocene (9000-6000 yrs BP), sea ice was more abundant rather than today. Micropaleontological and geochemical data clarified that during early and middle Holocene Coccolithopholid dominated diatom under the warm and less saline circumstance at that time. These facts suggest a possibility that in Holocene the Okhotsk sea ice has expanded not by cooling but due to freshening of seawater.

Report

(3 results)
  • 2001 Annual Research Report   Final Research Report Summary
  • 2000 Annual Research Report
  • Research Products

    (14 results)

All Other

All Publications (14 results)

  • [Publications] Nakatsuka, T. et al.: "An extremely turbid intermediate water in the Sea of Okhotsk : Implication for the transport of particulate organic matter in a seasonally ice-bound sea"Geophysical Research Letters. (印刷中). (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Ternois, Y. et al.: "A biomarker approach for assessing marine and terrigenous inputs to the sediments of Sea of Okhotsk for the last 27,000 years"Geochimica et Cosmochimica Acta. 64. 791-802 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Seki, O. et al.: "Sediment core profiles of long-chain n-alkanes in the Sea of Okhotsk : Enhanced transport of terrestrial materials in the last deglacial to the early Holocene"Geophysical Research Letters. (印刷中). (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Kimura, N. et al.: "Mechanism for the variation of sea-ice extent in the Northern Hemisphere"Journal of Geophysical Research. 106. 31319-31332 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 中塚 武等: "窒素同位体海洋化学の展開 -オホーツク海を例として-"月刊海洋. 号外25. 114-120 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 田辺竜男等: "GHOO航海で採取されたオホーツク海南西部海底表層堆積物の粒度組成およびその起源"産業技術総合研究所平成12年度研究概要報告書 -オホーツク西方海域及び東海沖海域-. 33. 158-178 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Nakatsuka, T., C. Yoshikawa, M. Toda, K. Kawamura, M. Wakatsuchi: "An extremely turbid intermediate water in the Sea of Okhotsk : Implication for the transport of particulate organic carbon in a seasonally ice-bound sea"Geophysical Research Letters. in press. (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Ternois, Y., K. Kawamura, L. Keigwin, N. Ohkouchi, T. Nakatsuka: "A biomarker approach for assessing marine and terrigenous inputs to the sediments of Sea of Okhotsk for the last 27,000 years"Geochimica et Cosmochimica Acta. 65. 791-802 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Seki, O., K. Kawamura, T. Nakatsuka, K. Ohnishi, M. Ikehara, M. Wakatsuchi: "Sediment core profiles of long-chain n-alkanes in the Sea of Okhotsk : Enhanced transport of terrestrial materials in the last deglacial to the early Holocene"Geophysical Research Letters. (in press). (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Kimura, N., M. Wakatsuchi: "Mechanisms for the variation of sea-ice extent in the Northern Hemisphere"Journal of Geophysical Research. 106. 31319-31332 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] NaKatsuka, T., C. Yoshikawa, K. Ohnishi: "Development of nitrogen isotope marine chemistry - examples from the Sea of Okhotsk"Monthly Kaiyo. Supp. 25. 114-120 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Nakatsuka, T.: "An attempt to analyze nitrogen budget in a marginal sea using N^*"Monthly Kaiyo. 33. 518-522 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Tanabe, T., T. Sakamoto: "Size distribution of particles and their origins in surface sediments collected during GH00 cruise in the southwestern Sea of Okhotsk"Research Report of AIST- 2000- Western Sea of Okhotsk and Off Tokai Areas. 158-178 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Tanabe, T., T. Sakamoto: "Size and mineral compositions of terrigenous clastic materials and their origins in surface sediments collected during GH00 & GH01 cruises in the southwestern Sea of Okhotsk"Research Report of AIST -2001- Western Sea of Okhotsk and Off Tokai Areas. (in press). (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary

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Published: 2000-04-01   Modified: 2016-04-21  

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