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Diffusion and persistency of the freshwater cyanotoxin in the marine ecosystem.

Research Project

Project/Area Number 17K00639
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Environmental risk control and evaluation
Research InstitutionKumamoto Health Science University

Principal Investigator

Takahashi Tohru  熊本保健科学大学, 保健科学部, 教授 (70369122)

Co-Investigator(Kenkyū-buntansha) 正木 孝幸  熊本保健科学大学, 保健科学部, 教授 (00746232)
Project Period (FY) 2017-04-01 – 2020-03-31
Project Status Completed (Fiscal Year 2019)
Budget Amount *help
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Keywordsミクロシスチン / 分解菌 / 諌早湾調整池 / 生物濃縮 / HABs / ミクロキスティス / 一次純生産 / ミクロシスチン合成酵素 / ミクロシスチン分解酵素 / 生分解性 / シアノバクテリア / シアノトキシン
Outline of Final Research Achievements

The blooming of toxic cyanobacteria has become an annual event constant in the Isahaya Bay reservoir from the summer to the autumn. Our 24hrs consecutive field survey estimated that about 52kg of strong hepatotoxin, microcystines (MCs) was produced and 40% of them deposited in the bottom in the blooming season. MCs spreads with drainage in the sea area. However, cyanobacteria of the fresh water origin are thought to perish and MCs are degraded in the sea area, and has not attracted attention. However, laboratory experiment revealed that the MCs are not degraded at less than 20C, and it was confirmed by real time PCR that the bacterial degrading did not function. This support the result of field survey that MCs content of the Ariake Sea’s sediment is higher in winter (non-blooming season of cyanobacteria) than that in summer (blooming season).

Academic Significance and Societal Importance of the Research Achievements

大規模な有毒シアノバクテリアの発生は世界各地で報告されているが、淡水域で産生された毒素の行方や分解過程については未解明な点が多い。今回、我々は、窒素消費からミクロシスチンの産生量を推定し、その分解は低温では進まないことを示した。そのため、海域生態系には未分解のミクロシスチンが残留・循環している事が示された。もちろん、この事は有明海特有の現象ではない。例えば、韓国ナクトンガンの河口域で厳冬期に採取された堆積物に高い濃度のMCsが残留している事が確認された。したがって、今後は、有毒アオコ発生時には下流のエコトーンから海域に至る調査が必要である事を示した。

Report

(4 results)
  • 2019 Annual Research Report   Final Research Report ( PDF )
  • 2018 Research-status Report
  • 2017 Research-status Report
  • Research Products

    (11 results)

All 2019 2017

All Journal Article (5 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 3 results,  Open Access: 1 results) Presentation (5 results) (of which Int'l Joint Research: 2 results,  Invited: 1 results) Book (1 results)

  • [Journal Article] 潮受け堤防による海域生態系の疲弊に追い打ちをかける調整池排水2019

    • Author(s)
      髙橋 徹
    • Journal Title

      日本ベントス学会誌

      Volume: 73(2) Pages: 123-128

    • Related Report
      2019 Annual Research Report 2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] Estimation of production and sedimentation of cyanobacterial toxins (microcystin) based on nutrient budgets in the reservoir of Isahaya Bay, Japan2019

    • Author(s)
      Umehara A, Komorita T, Takahashi T, Tsytsumi H
    • Journal Title

      Ecotoxicology and Environmental Safety

      Volume: 183 Pages: 109477-109484

    • DOI

      10.1016/j.ecoenv.2019.109477

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Widespread dispersal and bio-accumulation of toxic microcystins in benthic marine ecosystems.2017

    • Author(s)
      Umeharra A, Takahashi T, Komorita T, Orita R, Choi JW, Takenaka R,Mabuchi R, Park HD, Tsutsumi H.
    • Journal Title

      Chemosprehe

      Volume: 167 Pages: 492-500

    • DOI

      10.1016/j.chemosphere.2016.10.029

    • Related Report
      2017 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Bk\looming of toxic cyanobacteria in the Isahaya Bay reclaimed land reservoir, South Japan2017

    • Author(s)
      Tohru Takahashi, Akira Umehara
    • Journal Title

      有明海の環境と漁業

      Volume: 4 Pages: 19-28

    • Related Report
      2017 Research-status Report
    • Open Access
  • [Journal Article] 諫早湾調整池から排出された アオコ毒素ミクロシスチンは海域で消滅するのか?2017

    • Author(s)
      髙橋 徹
    • Journal Title

      有明海の環境と漁業

      Volume: 3 Pages: 25-29

    • Related Report
      2017 Research-status Report
  • [Presentation] Microcystine (freshwater origin cyanotoxin) hibernates in the sea bottom2019

    • Author(s)
      Takahashi T, Umehara A
    • Organizer
      The 4th Asian Marine Biology Symposium
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 淡水産アオコ毒素ミクロシスチンによる有明海の汚染2017

    • Author(s)
      髙橋 徹、梅原 亮
    • Organizer
      熊本生物研究会
    • Related Report
      2017 Research-status Report
  • [Presentation] Pollution of the shore ecosystem with microcystins (hepatotoxic cyanotoxin) derived from fresh water cyanobacteria2017

    • Author(s)
      Tohru TAkahashi, Akira Umehara
    • Organizer
      3rd Asian Marine Biology Symposium
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research
  • [Presentation] 潮受け堤防による海域生態系の疲弊に追い打ちをかける調整池排水2017

    • Author(s)
      髙橋 徹
    • Organizer
      日本プランクトン学会日本ベントス学会合同大会
    • Related Report
      2017 Research-status Report
  • [Presentation] 韓国大河川のアオコ大発生と推測される海域汚染2017

    • Author(s)
      髙橋 徹
    • Organizer
      ソウル市民大学
    • Related Report
      2017 Research-status Report
    • Invited
  • [Book] いのち輝く有明海を2019

    • Author(s)
      田中克 他
    • Total Pages
      311
    • Publisher
      花乱社
    • ISBN
      9784910038094
    • Related Report
      2019 Annual Research Report

URL: 

Published: 2017-04-28   Modified: 2021-02-19  

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