Distribution of prokaryotic picophytoplankton from Seto Inland Sea to the Kuroshio region, with special reference to ‘Kyucho’ events

Aquatic Microbial Ecology

Goh Onitsuka¹  Sotaro Mizutani¹  Toshiya Katano¹  Yumiko Obayashi¹  Hideichi Yasuda¹  Hidetaka Takeoka¹  Kazuhiro Hata¹  Yoshihide Kon¹  Naoto Kanzaki¹  Akihiko Morimoto¹  Atsushi Kaneda¹  Shin-ichi Nakano¹ 

关键词: Prochlorococcus;    Synechococcus;    Kyucho;    Kuroshio;    Phycoerythrin;    Pigment type;    Advection;    Dual laser flow cytometry;    Spectrofluorometry;   

DOI  :  10.3354/ame046191

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: A ‘Kyucho’ (an intrusion of warm surface water) occurs in the Bungo Channel, located in southwestern Japan. The abundances of Prochlorococcus and Synechococcus during a Kyucho, together with physical and chemical environmental factors, were investigated from the Kuroshio region to the Seto Inland Sea, via Bungo Channel, from 26 November to 5 December 2003. With the occurrence of the Kyucho, oceanic water intruded from the Kuroshio region into the middle of the Bungo Channel. The abundance of Prochlorococcus was the highest in the Kuroshio region and the southern part of the Bungo Channel (>25 × 10³ cells ml^–1), low in the northern part of the Bungo Channel (<1 × 10³ cells ml^–1), and below detection levels in the Seto Inland Sea. A relatively high abundance of Synechococcus cells (>15 × 10³ cells ml^–1) was detected in the Kuroshio region and in the southern part of the Bungo Channel, but the abundance (<6 × 10³ cells ml^–1) was low in other regions. In the Kuroshio region and the southern part of the Bungo Channel, high-phycourobilin (PUB)-type cells were dominant (>90%); at this location, most of the available light in the deeper layer (>25 m depth) was in the 450 to 500 nm range, corresponding to the peak absorbance of PUB. In contrast, the abundance of low-PUB-type cells accounted for >75% of the total in the northern part of the Bungo Channel and in the Seto Inland Sea, where most of the available light in the deeper layer (>10 m depth) was in the 480 to 560 nm range, including the peak absorbance of both PUB and phycoerythrobilin (PEB). These results indicate that Synechococcus cells of high-PUB type, which have a higher Ex 495:545 (>1.5; ratio of orange fluorescence intensity excited at 495 nm to that at 545 nm), as well as Prochlorococcus cells were advected to the Bungo Channel by the Kyucho. The co-occurrence of the 2 pigment types of Synechococcus in coastal waters is highly affected by a physical process, such as the Kyucho.

【 授权许可】

Unknown