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Influence of changes in lake water circulation processes due to global warming on denitrification in the sediment at Lake Biwa

Research Project

Project/Area Number 20H04311
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Review Section Basic Section 63010:Environmental dynamic analysis-related
Research InstitutionThe University of Shiga Prefecture

Principal Investigator

Osaka Ken'ichi  滋賀県立大学, 環境科学部, 准教授 (30455266)

Co-Investigator(Kenkyū-buntansha) 佐藤 祐一  滋賀県琵琶湖環境科学研究センター, 総合解析部門, 専門研究員 (30450878)
後藤 直成  滋賀県立大学, 環境科学部, 教授 (40336722)
中村 高志  山梨大学, 大学院総合研究部, 准教授 (60538057)
西田 継  山梨大学, 大学院総合研究部, 教授 (70293438)
細井 祥子 (田辺祥子)  滋賀県立大学, 環境科学部, 准教授 (80423226)
木庭 啓介  京都大学, 生態学研究センター, 教授 (90311745)
Project Period (FY) 2020-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥17,160,000 (Direct Cost: ¥13,200,000、Indirect Cost: ¥3,960,000)
Fiscal Year 2022: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2021: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2020: ¥10,660,000 (Direct Cost: ¥8,200,000、Indirect Cost: ¥2,460,000)
Keywords窒素循環 / 温暖化 / 成層 / 同位体 / 微生物 / 溶存酸素 / 降雨 / 1 / 窒素化合物 / 湖底堆積物 / 琵琶湖 / 溶存酸素濃度 / 貧酸素化 / 湖沼 / 脱窒 / 全層循環 / 安定同位体比 / MIMS
Outline of Research at the Start

湖沼やダム湖では、微生物反応である脱窒により堆積物中で窒素が除去されていることが指摘されているが、その程度や、温暖化に伴う湖水循環過程の変化が脱窒や窒素循環過程に与える影響は十分に明らかになっていない。本課題では、温暖化により湖水循環過程が変化しつつある琵琶湖を対象に、湖底堆積物中の脱窒とそれに影響を与える要因を明らかにする。同時に、微生物群集構造解析、機能遺伝子発現量から湖底堆積物中の微生物動態を描くこと、琵琶湖の窒素収支を測定することにより、湖底堆積物中の脱窒量・プロセスとそれに対する湖水循環過程の変化による影響を解明する。

Outline of Final Research Achievements

We developed the column method to clarify the effect of dissolved oxygen concentration in the lake bottom on the rate of dissolved nitrogen exchange between lake bottom sediments and lake water. Using this method, the dissolved nitrogen exchange rate between lake sediments and lake water in Lake Biwa was measured. It was found that about 10% of the total dissolved nitrogen in the water of Lake Biwa is supplied from the lake bottom sediments to the lake water in one year, and this amount increases with a decrease in the dissolved oxygen concentration in the lake bottom. However, the amount of dissolved nitrogen pooled in Lake Biwa water in 2019 and 2020, when the winter total circulation was weaker than usual and the dissolved oxygen concentration in the lake bottom was lower than usual, was lower than usual. This suggests that consumption of dissolved nitrogen in the lake occurred more than the increased supply of dissolved nitrogen from the lake bottom sediments to the lake water.

Academic Significance and Societal Importance of the Research Achievements

世界各地の湖沼において、地球温暖化により表層水温が上昇することで湖水の鉛直循環過程が変化し、それによる湖水深層での溶存酸素濃度の低下や栄養塩の放出が問題となっている。本研究は湖水深層での溶存酸素濃度の低下が湖底堆積物と湖水間の窒素化合物交換速度に与える影響を明らかにするための手法を提示し、今後の地球温暖化に対する湖沼の応答に関する研究分野に貢献した。また近畿1400万人の飲料水を賄っている琵琶湖における窒素動態に関する重要な知見を得ることができた。

Report

(4 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Annual Research Report
  • 2020 Annual Research Report
  • Research Products

    (15 results)

All 2022 2021 Other

All Journal Article (2 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 2 results,  Open Access: 1 results) Presentation (12 results) (of which Int'l Joint Research: 5 results) Remarks (1 results)

  • [Journal Article] Hydrological control of the chemical characteristics of suspended particulate phosphorus in the Yasu River watershed, Japan: Implications for its source and bioavailability2022

    • Author(s)
      Osaka, K., Chishiro, S., Matsumoto, Y., Iwata T., Okuda, N.
    • Journal Title

      Hydrological Processes

      Volume: 36(10) Issue: 10

    • DOI

      10.1002/hyp.14734

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Effect of dissolved oxygen on nitrogen and phosphorus fluxes from lake sediments and their thresholds based on incubation using a simple and stable dissolved oxygen control method2021

    • Author(s)
      Osaka Ken'ichi, Yokoyama Rei, Ishibashi Takaaki, Goto Naoshige
    • Journal Title

      Limnology and Oceanography: Methods

      Volume: 20 Issue: 1 Pages: 1-14

    • DOI

      10.1002/lom3.10466

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] FIAを用いた琵琶湖底堆積物からの栄養塩溶出速度の測定2022

    • Author(s)
      尾坂兼一,横山粱,石橋孝晃,後藤直成
    • Organizer
      第58回フローインジェクション分析講演会
    • Related Report
      2022 Annual Research Report
  • [Presentation] 琵琶湖における内部栄養塩負荷測定: 任意の溶存酸素濃度による湖底堆積物カラム培養法の検討2022

    • Author(s)
      尾坂兼一,横山粱,石橋孝晃,後藤直成
    • Organizer
      陸水学会第86回大会
    • Related Report
      2022 Annual Research Report
  • [Presentation] 琵琶湖における湖底からの栄養塩負荷の季節変動2022

    • Author(s)
      石橋孝晃, 大手 信人, 尾坂 兼一, 冨岡 知玄
    • Organizer
      第57回日本水環境学会年会
    • Related Report
      2022 Annual Research Report
  • [Presentation] Kiryu Experimental Watershed: the temperate forest catchment under Asian monsoon climate, Frontiers in Hydrology2022

    • Author(s)
      Ohte, N., Katsuyama, M., Osaka, K.
    • Organizer
      Frontiers in Hydrology
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] The influence of vertical water mixing on inter-annual nitrogen dynamics in Lake Biwa2021

    • Author(s)
      Takaaki Ishibashi, Ken’ichi Osaka, Keisuke Koba, Kei Nishida, Takashi Nakamura
    • Organizer
      JpGU meeting 2021
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Hydrological controls on phosphorus export from diffuse source in Lake Biwa basin, central Japan2021

    • Author(s)
      Ken’ichi Osaka, Haruto Tanabe, Syuhei Ban
    • Organizer
      JpGU meeting 2021
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] High resolution monitoring for subsidiary nutrient loadings and phytoplankton production in north basin of Lake Biwa2021

    • Author(s)
      Ban, S., X. Liu, K. Osaka, N. Goto and J.C. Wells
    • Organizer
      JpGU meeting 2021
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Monitoring and particle-tracking simulation to clarify littoral-to-pelagic nutrient export during the rice planting season in Lake Biwa2021

    • Author(s)
      Wells, J., S. Ban, X. Liu, K. Osaka and N. Goto
    • Organizer
      JpGU meeting 2021
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Particle tracking simulations of littoral to pelagic transport in the North Basin of Lake Biwa during the rice-planting season of 20202021

    • Author(s)
      Wells, John, 伴修平, X. Liu, 尾坂兼一, 後藤直成
    • Organizer
      日本陸水学会2021年大会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 琵琶湖集水域における河川のリン濃度と土地利用に対する水文条件の影響2021

    • Author(s)
      尾坂兼一, 田邊晴人, 石橋孝晃, 伴修平
    • Organizer
      日本陸水学会2021年大会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 集水域から琵琶湖に流入する窒素化合物に対する土地利用と水文環境の影響2021

    • Author(s)
      尾坂兼一, 田邊晴人, 佐藤祐一, 中村高志
    • Organizer
      第37回日本腐植物質学会講演会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 琵琶湖水の窒素動態に及ぼす湖水循環の影響2021

    • Author(s)
      石橋孝晃, 大手信人, 尾坂兼一, 木庭啓介, 西田継, 中村高志
    • Organizer
      第56回日本水環境学会年会
    • Related Report
      2021 Annual Research Report
  • [Remarks] 知のリソース(尾坂兼一)

    • URL

      http://db.spins.usp.ac.jp/html/100000141_ronbn_1_ja.html

    • Related Report
      2020 Annual Research Report

URL: 

Published: 2020-04-28   Modified: 2024-01-30  

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