[A-OS12] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS12-P01] Impact of mesoscale eddies on particulate organic carbon flux in the western subarctic North Pacific

*土橋 稜¹、上野 洋路²、松寺 望³、藤田 功⁴、藤木 徹一⁵、本多 牧生⁵、原田 尚美⁵ (1.北海道大学 大学院水産科学院 (現在の所属：University of Hawaii at Manoa)、2.北海道大学 大学院水産科学研究院、3.北海道大学 大学院 環境科学院、4.北海道大学 大学院水産科学院、5.国立研究開発法人海洋研究開発機構)

キーワード：北太平洋西部亜寒帯、粒子態有機炭素、海洋中規模渦

The mechanism that controls particulate organic carbon (POC) flux in the deep sea differs depending on the season and sea. The POC produced in the western subarctic North Pacific are known to be transported to the deep sea efficiently, but the direct relationship between the POC flux and physical processes is still unclear. In this study, we evaluated the effect of mesoscale eddies on POC flux in the western subarctic North Pacific. The seasonal and interannual variabilities of POC flux were investigated using data from a time-series sediment trap deployed at 4,810 m at station K2 (47°N, 160°E) from 2005 to 2018. POC flux was high during May–November, appearing to reflect spring and fall blooms at the ocean surface. POC flux also showed interannual variability, with twelve peaks that were mostly affected by enhanced bloom just before the peak. Nine peaks of the twelve peaks were affected by mesoscale eddies, which enhanced bloom around K2 by extending the area with a high chlorophyll-a concentration along the coastal region into the offshore region, suggesting that mesoscale eddies strongly impact the interannual variability of POC flux at K2.