Lin Yun-Chi, Chung Chih-Ching, Chen Liang-Yin, Gong Gwo-Ching, Huang Chin-Yi, Chiang Kuo-Ping
Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung, 20224, Taiwan.
Institute of Marine Biology, National Taiwan Ocean University, Keelung, 20224, Taiwan.
J Eukaryot Microbiol. 2017 May;64(3):349-359. doi: 10.1111/jeu.12370. Epub 2016 Oct 13.
Photosynthetic picoeukaryotes (PPEs) are important constituents in picoplankton communities in many marine ecosystems. However, little is known about their community composition in the subtropical coastal waters of the Northwestern Pacific Ocean. In order to study their taxonomic composition, this study constructed 18S rRNA gene libraries using flow cytometric sorting during the warm season. The results show that, after diatoms, prasinophyte clones are numerically dominant. Within prasinophytes, Micromonas produced the most common sequences, and included clades II, III, IV, and VI. We are establishing the new Micromonas clade VI based on our phylogenetic analysis. Sequences of this clade have previously been retrieved from the South China Sea and Red Sea, indicating a worldwide distribution, but this is the first study to detect clade VI in the coastal waters of Taiwan. The TSA-FISH results indicated that Micromonas clade VI peaked in the summer (~4 × 10 cells/ml), accounting for one-fifth of Micromonas abundance on average. Overall, Micromonas contributed half of Mamiellophyceae abundance, while Mamiellophyceae contributed 40% of PPE abundance. This study demonstrates the importance of Micromonas within the Mamiellophyceae in a subtropical coastal ecosystem.
光合微微型真核生物（PPEs）是许多海洋生态系统中微微型浮游生物群落的重要组成部分。然而，对于西北太平洋亚热带沿海水域中它们的群落组成，人们了解甚少。为了研究其分类组成，本研究在温暖季节利用流式细胞术分选构建了18S rRNA基因文库。结果表明，除硅藻外，绿藻纲克隆在数量上占主导地位。在绿藻纲中，微小单胞藻产生的序列最为常见，包括第二、三、四和六进化枝。基于系统发育分析，我们正在建立新的微小单胞藻第六进化枝。此前已从南海和红海检索到该进化枝的序列，表明其分布于全球，但这是首次在台湾沿海水域检测到第六进化枝。全细胞荧光原位杂交（TSA-FISH）结果表明，微小单胞藻第六进化枝在夏季达到峰值（约4×10 个细胞/毫升），平均占微小单胞藻丰度的五分之一。总体而言，微小单胞藻占绿藻纲丰度的一半，而绿藻纲占PPE丰度的40%。本研究证明了微小单胞藻在亚热带沿海生态系统中绿藻纲内的重要性。
