日本地球惑星科学連合2023年大会

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[J] 口頭発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS08] 南大洋・南極氷床が駆動する全球気候変動

2023年5月26日(金) 10:45 〜 12:00 103 (幕張メッセ国際会議場)

コンビーナ:草原 和弥(海洋研究開発機構)、箕輪 昌紘(北海道大学・低温科学研究所)、野木 義史(国立極地研究所)、関 宰(北海道大学低温科学研究所)、座長:箕輪 昌紘(北海道大学・低温科学研究所)

11:45 〜 12:00

[MIS08-11] Phytoplankton response to the Southern annular mode and El Niño-Southern Oscillation in the Southern Ocean

*溝端 浩平1、藤田 萌永1 (1.東京海洋大学)

キーワード:南大洋、植物プランクトン、南半球環状モード、エルニーニョ・南方振動

The mechanisms of variation in the abundance and distribution of phytoplankton in the Southern Ocean, which is considered a sink for anthropogenic CO2, remain largely unknown. Spatiotemporal variations in phytoplankton distribution have so far been attributed to factors such as sea ice distribution at the local scale and surface mixed layer thickness at the ocean basin scale. Recently, the response of phytoplankton to the Southern Annular mode (SAM), a major climate driver, has been discussed, but it does not fully explain the phytoplankton variability in the Southern Ocean, including the Antarctic coastal region. On the other hand, it is known that oceanic environmental changes that significantly affect phytoplankton are not only caused by SAM but also by El Niño–Southern Oscillation (ENSO) events, whereas the response of phytoplankton to ENSO events has not been discussed. In this study, statistical analyses on satellite data and climate reanalysis data were conducted to investigate the response of phytoplankton to two major climate patterns. The results show that the spatio-temporal variability of phytoplankton distribution and abundance in the Southern Ocean can be explained by the SAM and ENSO indices. The results also suggest that the dominant factors of phytoplankton variability differ among the Atlantic, Pacific, and Indian Ocean sectors, even under the same climate pattern. Furthermore, in views of future global warming scenarios, it is expected that primary production will decrease in the Pacific and Indian Ocean sectors in the future, while it will increase in the Atlantic sector.