2019 Fiscal Year Final Research Report
Ocean acidification in the subarctic western North Pacific Ocean and its impact on marine biology
| Project/Area Number |
15H02835
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Environmental impact assessment
|
|---|
| Research Institution | Japan Agency for Marine-Earth Science and Technology |
|---|
Principal Investigator |
WAKITA Masahide 国立研究開発法人海洋研究開発機構, 地球環境部門(むつ研究所), 技術研究員 (30415989)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
中野 善之 国立研究開発法人海洋研究開発機構, 研究プラットフォーム運用開発部門, 技術研究員 (20566103)
永野 憲 国立研究開発法人海洋研究開発機構, 地球環境部門(海洋観測研究センター), 主任研究員 (40421888)
|
|---|
| Project Period (FY) |
2015-04-01 – 2020-03-31
|
| Keywords | 海洋環境変動 / 海洋酸性化 / 海洋環境評価 |
|---|
| Outline of Final Research Achievements |
Rising atmospheric CO2 contents have led to greater CO2 uptake by the oceans, lowering both pH and CaCO3 saturation states. Here, we used CO2 system data collected during 1997-2019 to investigate ocean acidification at time series sites in the western subarctic region of the North Pacific Ocean. The annual mean pH at station K2 decreased mostly in response to oceanic uptake of anthropogenic CO2. The pH during the winter decline at a slower rate. This was attributed to a reduced rate of increase of dissolved inorganic carbon (DIC) and an increase of total alkalinity (TA). The reduction of DIC increase was caused by the decline of surface water density associated with the pycnocline depression and the reduction of vertical diffusion flux from the upper pycnocline due to wind-driven northward shrinkage of the western subarctic gyre. Meanwhile, the winter TA increase might be caused mainly by the accumulation of TA due to the weakened calcification by organisms during the winter.
|
| Free Research Field |
海洋学
|
| Academic Significance and Societal Importance of the Research Achievements |
西部北太平洋亜寒帯域は、外洋域で最も早く炭酸カルシウムの化学的飽和度が未飽和になると予測されている海域で、時系列観測を実施し、特異な酸性化の進行とメカニズムを調べ、生物影響評価することは、今後起こり得る他の海域へ応用する上で非常に重要である。加えて、酸性化の進行は、食物網の底辺を支える低次生物のプランクトンが被害を受け、サケ、サンマなどに代表される我が国の豊かな水産資源を支える西部亜寒帯循環の生態系や水産資源が劇変するかもしれない。その影響を、船舶と係留系による時系列観測を基に酸性化進行の解明は、将来の地球環境変化と水産資源の変動予測の向上に貢献できるため、我が国として喫緊の研究課題である。
|
