Effect of ocean acidification on the marine bacterial microbial carbon pump

• Project/Area Number: 16H02967
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental impact assessment
• Research Institution: University of Tsukuba
• Principal Investigator: HAMA Takeo 筑波大学, 生命環境系, 名誉教授 (30156385)
• Co-Investigator(Kenkyū-buntansha): 小杉 如央 気象庁気象研究所, 海洋・地球化学研究部, 研究官 (20553168) ; 稲垣 祐司 筑波大学, 計算科学研究センター, 教授 (50387958) ; 大森 裕子 筑波大学, 生命環境系, 助教 (80613497) ; 笹野 大輔 気象庁気象研究所, 海洋・地球化学研究部, 研究官 (10462524)
• Research Collaborator: YOSHIDA yusuke
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥18,200,000 (Direct Cost: ¥14,000,000、Indirect Cost: ¥4,200,000); Fiscal Year 2018: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2017: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2016: ¥11,050,000 (Direct Cost: ¥8,500,000、Indirect Cost: ¥2,550,000)
• Keywords: 微生物炭素ポンプ / 海洋酸性化 / バクテリア / 難分解性溶存態有機物 / バクテリア分類群 / 難分解性溶存態有機炭素 / 微生物ポンプ / バクテリア群集 / 蛍光性溶存態有機物 / 海洋バクテリア

Outline of Final Research Achievements

Marine bacterial population produce the recalcitrant organic matter using labile organic matter. This process has been called as "Microbial carbon pump," and it can be regarded as the bacterial role isolating carbon as refractory products. In this study, bacterial culture experiment was carried out to elucidate the effect of ocean acidification on microbial carbon pump. The elevated carbon dioxide by 2 times (800 micro atm) had a minor effect on the efficiency of microbial carbon pump. This result suggests that ocean acidification coming 100 years has infignificant effect on microbial carbon pump.

Academic Significance and Societal Importance of the Research Achievements

海洋酸性化が生態系に与える影響に関しては、主として大型生物を対象に研究が行われてきた。一方、バクテリアに対する影響の評価は、ほとんど実施されて来ていない。特に、バクテリアが有する長期炭素隔離機能（微生物炭素ポンプ）に対する影響に関して、得られている情報は少ない。本研究において、現在の2倍の二酸化炭素濃度の条件下では、バクテリアの長期炭素隔離機能は大きな影響を受けないことを明らかにした。一方、バクテリアの群集組成は、酸性化の影響を受けて変化する結果が得られたことから、今後の詳細な研究が必要と考えられる。

Research Products

• [Journal Article] Production and degradation of fluorescent dissolved organic matter derived from bacteria (2018)
  • Author(s): Arai Ken、Wada Shigeki、Shimotori Koichi、Omori Yuko、Hama Takeo
  • Journal Title: Journal of Oceanography Volume: 74 Issue: 1 Pages: 39-52
  • DOI: 10.1007/s10872-017-0436-y
  • NAID: 40021449690
  • Peer Reviewed / Open Access
• [Presentation] Effect of ocean acidification on production of the recalcitrant dissolved organic carbon (2018)
  • Author(s): Takeo Hama, Yusuke Yosida, Yuji Inagaki, Yuko Omori, Shigeki Wada
  • Organizer: 47th Estuarine and Coastal Sciences Association
  • Int'l Joint Research
• [Presentation] 海洋酸性化-もう一つの二酸化炭素問題 (2018)
  • Author(s): 濱 健夫
  • Organizer: 獨協大学環境共生研究所研究例会
• [Presentation] Experimental analysis on the dynamics of humic-like fluorescence dissolved organic matter in the marine surface layer (2018)
  • Author(s): Akira Saeki, Yuko Omori, Shigeki Wada and Takeo Hama
  • Organizer: Ocean Sciences Meeting
  • Int'l Joint Research
• [Presentation] Microbial and photochemical decomposition of dissolved organic matter collected from macroalgal bed (2018)
  • Author(s): Eri Iwasawa, Shigeki Wada, Yuko Omori and Takeo Hama
  • Organizer: Ocean Sciences Meeting
  • Int'l Joint Research
• [Presentation] Effects of ocean acidification on phytoplankton community and biogeochemical cycle (2016)
  • Author(s): 濱 健夫
  • Organizer: JAMBIO国際シンポジウム
  • Place of Presentation: 筑波大学東京キャンパス（東京都・文京区）
  • Year and Date: 2016-09-21
  • Int'l Joint Research
• [Presentation] 海洋溶存態有機物の代謝と安定性 (2016)
  • Author(s): 濱 健夫
  • Organizer: 日本地球化学会年会
  • Place of Presentation: 大阪市立大学（大阪府・大阪市）
  • Year and Date: 2016-09-14
  • Invited