黒潮再循環域の表層・亜表層における生物地球化学的循環の解明

• Project Area: Ocean Mixing Processes: Impact on Biogeochemistry, Climate and Ecosystem
• Project/Area Number: 16H01594
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Complex systems
• Research Institution: Japan, Meteorological Research Institute
• Principal Investigator: 石井 雅男 気象庁気象研究所, 海洋・地球化学研究部, 室長 (70354553)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥10,790,000 (Direct Cost: ¥8,300,000、Indirect Cost: ¥2,490,000); Fiscal Year 2017: ¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000); Fiscal Year 2016: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
• Keywords: 黒潮再循環 / 海洋物質循環 / 酸素極大層 / 人為起源二酸化炭素 / 海洋科学 / 気候変動 / 地球化学 / 海洋生物地球化学 / 硝酸躍層

Outline of Annual Research Achievements

日本列島の南から南東の沖合に広がる黒潮再循環域を４次元的にとらえ、その内部と周辺域で、生物生産を支える自然の物質循環と、大気中のCO2濃度の増加を抑制する海洋への人為起源CO2蓄積について、中規模渦から循環域全体まで、季節内変化や長期変化を対象として、以下のように包括的に理解を進展させることができた。
人為的なCO2排出量の増加に伴う大気CO2濃度の加速傾向に応じて、海洋表層の全炭酸濃度とCO2分圧の増加も加速傾向にあることを、気象庁が観測船凌風丸と啓風丸で1980年代初めから東経137度で長期に行っている観測のデータに基づいて、黒潮再循環域で世界に先がけて明らかにできた。
平成28年度に作成した気象庁海洋各層観測データのデータプロダクトを活用して、黒潮再循環域の水深300m付近に分布する亜熱帯モード水内の全炭酸濃度の時間・空間変動と、その原因の解析を進めた。その結果から、亜熱帯モード水が、海洋表層から海洋内部に人為起源CO2を輸送し、蓄積する役割を担っていることを実証できた。同様に海洋表層から海洋内部への人為起源CO2の主要な輸送窓口となっていると推定される三陸沖の亜熱帯・亜寒帯移行領域などで、航走観測による海洋表層の全アルカリ度の高解像度観測を、平成29年10月～12月に白鳳丸KH-17-5次航海で成功させることができた。そのデータに基づいて、この海域の表層水に対する亜熱帯水と亜寒帯水の混合率を評価した。
水中グライダーによる低気圧性中規模渦の高解像度断面観測を、平成29年5～6月に伊豆・小笠原海嶺近傍で成功させることができた。中規模渦の中心付近の亜表層では、塩分が低く、酸素濃度が高いことから、渦による上方への栄養塩輸送が、生物生産を高める役割を果たしていると考えられる。

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] プリンストン大学/海洋大気局太平洋海洋環境研究所(米国)
• [Int'l Joint Research] チューリッヒ工科大学(スイス)
• [Int'l Joint Research] ベルゲン大学(ノルウェー)
• [Int'l Joint Research] 中山大学(中華民国)
• [Int'l Joint Research] プリンストン大学(米国)
• [Int'l Joint Research] ソウル国立大学(韓国)
• [Journal Article] Decline and bidecadal oscillation of dissolved oxygen in the Oyashio region and their propagation to the western North Pacific (2018)
  • Author(s): Sasano, D., Y. Takatani, N. Kosugi, T. Nakano, T. Midorikawa, M. Ishii
  • Journal Title: Global Biogeochemical Cycles Volume: 印刷中
  • Peer Reviewed
• [Journal Article] Fifty years of the 137°E repeat hydrographic section in the western North Pacific Ocean (2018)
  • Author(s): Oka Eitarou、Ishii Masao、Nakano Toshiya、Suga Toshio、Kouketsu Shinya、Miyamoto Masatoshi、Nakano Hideyuki、Qiu Bo、Sugimoto Shusaku、Takatani Yusuke
  • Journal Title: Journal of Oceanography Volume: 74 Issue: 2 Pages: 115-145
  • DOI: 10.1007/s10872-017-0461-x
  • NAID: 40021494755
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Rapid decline in pH of coral calcification fluid due to incorporation of anthropogenic CO2 (2017)
  • Author(s): Kubota Kaoru、Yokoyama Yusuke、Ishikawa Tsuyoshi、Suzuki Atsushi、Ishii Masao
  • Journal Title: Scientific Reports Volume: 7 Issue: 1 Pages: 1-9
  • DOI: 10.1038/s41598-017-07680-0
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Large Reemergence of Anthropogenic Carbon into the Ocean’s Surface Mixed Layer Sustained by the Ocean’s Overturning Circulation (2017)
  • Author(s): Toyama Katsuya、Rodgers Keith B.、Blanke Bruno、Iudicone Daniele、Ishii Masao、Aumont Olivier、Sarmiento Jorge L.
  • Journal Title: Journal of Climate Volume: 30 Issue: 21 Pages: 8615-8631
  • DOI: 10.1175/jcli-d-16-0725.1
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Deep oceans may acidify faster than anticipated due to global warming (2017)
  • Author(s): Chen Chen-Tung Arthur、Lui Hon-Kit、Hsieh Chia-Han、Yanagi Tetsuo、Kosugi Naohiro、Ishii Masao、Gong Gwo-Ching
  • Journal Title: Nature Climate Change Volume: 7 Issue: 12 Pages: 890-894
  • DOI: 10.1038/s41558-017-0003-y
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Up to half of the net 21st century ocean carbon-climate feedback sustained by ocean chemistry feedback (2018)
  • Author(s): Rodgers, K. B., T. L. Froelicher, S. Schlunegger, M. Ishii, A.J. Fassbender, Y. Plancherel, R. Slater, K. Toyama
  • Organizer: Ocean Sciences Meeting 2018
  • Int'l Joint Research
• [Presentation] Progress of ocean acidification in the western North Pacific (2017)
  • Author(s): Ishii, M.
  • Organizer: 温暖化・海洋酸性化の研究と対策に関する国際会
  • Place of Presentation: 東京都千代田区 海洋政策研究所
  • Year and Date: 2017-01-19
  • Int'l Joint Research / Invited
• [Presentation] Acceleration of the ocean acidification in the western North Pacific subtropical zone: a rapid response to the CO2 increase in the atmosphere (2017)
  • Author(s): Ishii, M., H. Ono, K. Toyama, N. Kosugi, D. Sasano, K. Enyo, S. Masuda, A. Kojima, Y. Iida, Y. Takatani, T. Nakano, H. Y. Inoue
  • Organizer: Ocean Sciences Meeting 2018
  • Int'l Joint Research
• [Presentation] 生物地球化学アルゴに期待される成果 (2017)
  • Author(s): 石井雅男
  • Organizer: 日本海洋学会 2017年度秋季大会
  • Invited
• [Presentation] 東経137 度線における表面海水中の全炭酸濃度増加の加速傾向 (2017)
  • Author(s): 小野恒, 小杉如央, 石井雅男, 小嶋惇, 飯田洋介, 髙谷祐介, 延与和敬, 中野俊也
  • Organizer: 日本海洋学会 2017年度秋季大会
• [Presentation] 北西太平洋亜熱帯域における水中グライダー観測 (2017)
  • Author(s): 遠山勝也, 小杉如央, 小野恒, 笹野大輔, 石井雅男
  • Organizer: 日本海洋学会 2017年度秋季大会
• [Presentation] Meridional gap in the oceanic CO2 increase associated with the overturning circulation of anthropogenic CO2 in the western North Pacific (2017)
  • Author(s): Ishii, M., D. Sasano, N. Kosugi, K. Toyama, K. Enyo, S. Masuda, Y. Iida, A. Kojima, H. Ono, Y. Takatani, T. Nakano, H. Y. Inoue, K. B. Rodgers
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] Concurrent underway measurements of surface pCO2 and total alkalinity in Kuroshio-Oyashio transition region (2017)
  • Author(s): Kosugi, N., D. Sasano, M. Ishii
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] Re-emergence of anthropogenic carbon through the ocean’s shallow overturning circulation (2017)
  • Author(s): Toyama, K, K. B. Rodgers, B. Blanke, D. Iudicone, M. Ishii, O. Aumont, J. L. Sarmiento
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] Decline and bidecadal oscillation of dissolved oxygen in the Oyashio region and their propagation to the western North Pacific (2017)
  • Author(s): Sasano, D., T. Yusuke, N. Kosugi, T. Nakano, T. Midorikawa, M. Ishii
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] A synthetic reconstruction of global surface ocean CO2 system parameters and sea-air CO2 flux (2017)
  • Author(s): Iida, Y. Y. Takatani, A. Kojima, S. Masuda, T. Nakano, M. Ishii
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] Rapid decline in pH of coral calcification fluid due to ocean acidification (2017)
  • Author(s): Kubota, K. Y. Yokoyama, T. Ishikawa, A. Suzuki, M. Ishii
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] A First-Order Role for the Low Latitudes in Sustaining Global Ocean Carbon-Climate Feedbacks (2017)
  • Author(s): Rodgers, K. B., M. Ishii, T. Frolicher
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] Global Trends in Ocean Dissolved Inorganic Carbon (2017)
  • Author(s): Olsen, A., R. M. Key, S. van Heuven, S. K. Lauvset, A. Velo, X. Lin, C. Schirnick, A. Kozyr, T. Tanhua, M. Hoppema, S. Jutterstrom, R. Steinfeldt, E. Jeansson, M. Ishii, F. F. Perez, T. Suzuki
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] Recent variability and trends in the global ocean carbon sink (2017)
  • Author(s): Gruber, N., D. Clement, P. Landschutzer, T. Tanhua, M. Ishii, J. T. Mathis, D. Bakker, R. A. Feely, R. M. Key, A. Olsen, S. van Heuven, R. Wanninkhof
  • Organizer: 10th International Carbon Dioxide Conference
  • Int'l Joint Research
• [Presentation] Meridional gap in the rate of ocean acidification between the subtropics and the tropics in the western North Pacific (2017)
  • Author(s): Ishii, M., D. Sasano, N. Kosugi, K. Toyama, H. Nakano, K. Enyo, Y. Takatani, S. Masuda, Y. Iida, A. Kojima, T. Nakano, K. B. Rodgers
  • Organizer: JpGU-AGU Joint Meeting 2017
  • Int'l Joint Research
• [Presentation] 西部北太平洋における溶存酸素の長期減少および周期変動とその広がり (2016)
  • Author(s): 笹野大輔, 石井雅男, 小杉如央, 緑川貴, 髙谷祐介, 中野俊也
  • Organizer: 2016年度日本海洋学会秋季大会
  • Place of Presentation: 鹿児島市 鹿児島大学
  • Year and Date: 2016-09-12
• [Presentation] The ocean acidification trend in the western equatorial Pacific for the past three decades (2016)
  • Author(s): Ishii, M., D. Sasano, N. Kosugi, K. Toyama, H. Nakano, H. Y. Inoue, K. B. Rodgers,
  • Organizer: JpGU-AGU Joint Meeting 2016
  • Place of Presentation: 千葉市 幕張メッセ
  • Year and Date: 2016-05-23
  • Int'l Joint Research
• [Presentation] Trends of oxygen with bidecadal oscillations in the Oyashio region and its propagation to the western North Pacific (2016)
  • Author(s): D. Sasano, Y. Takatani, N. Kosugi, T. Midorikawa, T. Nakano, M. Ishii
  • Organizer: JpGU-AGU Joint Meeting 2016
  • Place of Presentation: 千葉市 幕張メッセ
  • Year and Date: 2016-05-23
  • Int'l Joint Research
• [Book] 海の温暖化ー変わりゆく海と人間活動の影響ー (2017)
  • Author(s): 石井雅男, 笹野大輔, 中岡慎一郎, 小杉如央, 亀山宗彦, 川合美千代ほか
  • Total Pages: 168
  • Publisher: 朝倉書店
  • ISBN: 9784254161304
• [Book] 海の温暖化 (2017)
  • Author(s): 1.石井雅男，笹野大輔，中岡慎一郎，小杉如央、亀山宗彦、川合美千代 ほか
  • Publisher: 朝倉書店