2025-08-22 北海道大学
太平洋側北極海におけるマイクロプランクトン群集と海氷変動の模式図。一つのプランクトンシンボルは、2000 cells L-1を意味する。上段が海氷融解が早かった2019年、下段が通常の海氷融解時期であった2020年の結果を示す。
＜関連情報＞
- https://www.hokudai.ac.jp/news/2025/08/post-2025.html
- https://www.hokudai.ac.jp/news/pdf/250822_pr.pdf
- https://www.sciencedirect.com/science/article/pii/S1873965225000921?via%3Dihub
秋季太平洋側北極海におけるマイクロプランクトン群集に及ぼす早期海氷融解の影響 Influence of early sea ice melting on the autumn microplankton community of the Pacific Arctic Ocean
Kohei Sumiya, Dai Sumiyoshi, Kazutoshi Sato, Akihiko Murata, Shigeto Nishino, Kohei Matsuno
Polar Science Available online: 8 July 2025
DOI:https://doi.org/10.1016/j.polar.2025.101255
Highlights
- Protist communities in the Pacific Arctic Ocean were divided into six groups.
- Differences were observed in the microplankton communities between 2019 and 2020 in autumn.
- Early ice melting for 10 days changed hydrography, but not microplankton, in the MIZ.
- Ice melt a month early changed hydrography on the northern shelf, affecting protists.
Abstract
Sea ice in the Pacific Arctic Ocean has been rapidly decreasing over recent decades. However, knowledge of its effects on microplankton is limited. To elucidate the effect of sea ice reduction on the microplankton community of the Pacific Arctic Ocean, we examined the differences in the microplankton community and hydrography between 2019 and 2020. Based on the cluster analysis, the microplankton community was divided into six groups. In the southern Chukchi Sea, high cell densities were observed with high variability in group occurrence owing to the inflow of nutrient-rich Pacific water. In the northern Chukchi Sea, a 1-month inter-annual difference in sea ice melting timing induced changes in the microplankton community through hydrographical changes. Early sea ice melting stimulates the growth of phytoplankton species (Proboscia alata), which can utilize organic nitrogen compounds. In the marginal ice zone, a 10-day inter-annual difference in sea ice melting was observed, resulting in variations in hydrographic conditions; however, these changes did not affect the microplankton community. Our findings indicate that microplankton production and diversity respond differently to sea ice melting in varies by region in the Pacific Arctic Ocean.
