西部北太平洋155°E線に沿った春季植物プランクトン群集の水平および鉛直分布：多波長励起蛍光光度計による解析

• Main Authors: 松本, 健太郎, 有馬, 大地, 松野, 孝平, 山﨑, 康裕, 大西, 広二, 大木, 淳之, 平譯, 享, 山口, 篤, 今井, 一郎
• Format: Article in Journal/Newspaper
• Language: Japanese
• Published: 北海道大学大学院水産科学研究院
• Subjects: Chl. a sensor; Diatom; Dinoflagellate; Multi-excitation fluorometer; Phytoplankton; Spring bloom; 660; Pacific; Subarctic
• Online Access: http://hdl.handle.net/2115/61052; https://doi.org/10.14943/bull.fish.66.1.29

The spring phytoplankton community in the western North Pacific is characterized by large variability in both the horizontal and verical dimensions. To evaluate this variability, phytoplankton communitiesat 39°30'N-44°00'N along 155°E were investigated in situ using a multi-excitation fluorometer during May 2014. The sea surface chlorophyll a(Chi. a) level was high and composed mainly of diatoms near 43°30'N-42'N, while it was low and composed of dinoflagellates south of 40°N. Based on seven fixed-station investigations, the phytoplanklton communities were classified into 4 types : a low Chl. a level before bloom (44°N), massive diatom bloom(42°N-43°N), low Chl. a level with dinoflagellates(40°N-41°N) and lowest Chl.a(at the southernmost station at 39°30'N). These phytoplankton communities corresponded with the formation of a water mass separating the Subartctic front(SAF) and Subarctic boundary(SAB). Multi-excitation fluorometry data showed a high correlation with Chl. a measurements obtained via Thrmo-salinometer and biovolume microscopic analyses(r²=0.67-0.97,p<0.05). Thus, we concluded that a multi-excitation fluorometer can be applied for the evaluation of detailed spatial and temporal changes in the phytoplankton community at various locations.