【作者】 陈纪新；

【导师】 黄邦钦；

【作者基本信息】 厦门大学 ， 环境科学， 2006， 博士

【摘要】 本论文通过光合色素分析技术和小亚基核糖体RNA基因序列分析技术(ARDRA和DGGE)研究我国亚热带近海典型海区(包括陆架、河口、港湾、上升流区域等)超微型浮游植物光合色素组成和时空变化以及超微型真核浮游生物群落组成和多样性的时空变化,研究海域包括台湾海峡南部海域(2004年7月)、珠江口及南海北部(2004年2月和2004年7月)以及厦门海域(2003年3月、2003年5月、2003年8月、2003年12月、2004年2月、2004年5月和2004年9月),取得的主要结果如下:台湾海峡南部海域特征光合色素指示了九种超微型浮游植物类群在台湾海峡南部海域的分布,不同类群表现出对上升流过程的不同响应。超微型浮游植物的多数类群与营养盐呈显著正相关,受营养盐补充刺激生长;两种原核浮游植物蓝藻与原绿球藻的分布受营养盐限制。超微型浮游植物的类群组成具有明显垂直分布特征,蓝藻对CHLA生物量贡献随深度增加而下降,硅藻、青绿藻或定鞭金藻在真光层底部具有更高比重。构建了台湾海峡南部四个18S rDNA文库。在获得序列中,Novel Alveolates(NA)是基因文库中克隆丰度最高的类群;甲藻居第二;青绿藻是遗传文库中重要组成,存在与最小真核生物Ostreococcus sp.极相似的序列。聚类分析将超微型真核浮游生物遗传结构分为不同类型,超微型真核浮游生物遗传结构的水平分布空间变化明显,垂直分布差异较小。大量OTUs(Operational Taxonomy Units)的存在提供了各种环境条件的指示;在上升流海区的样品中,都存在着可能可以作为近岸上升流和台湾浅滩地形上升流指示的OTUs。厦门海域特征光合色素的分布表明硅藻、青绿藻、隐藻和绿藻是厦门海域超微型浮游植物的主要类群。超微型浮游植物类群结构的季节性变化较为明显,冬季叶绿素a最低,以硅藻、隐藻和青绿藻为主;夏季叶绿素a浓度最高,以硅藻为唯一的优势类群。超微型浮游植物类群结构的空间变化远小于季节性变化。在冬季与春季,超微型浮游植物类群主要受到温盐的影响,在夏、秋季,部分浮游植物类群,特别是青绿藻受磷酸盐影响明显。18S rDNA文库序列分析表明具有较更多还原

【Abstract】 Photosynthetic pigments analysis and molecular techniques including ARDRA and DGGE for analyzing small subunit ribosomal RNA(SSU rRNA or 18S rRNA) gene were applied to study temporal and spatial distributions of pigment composition and genetic diversity of ultra-plankton community in subtropical waters of China Seas, including the upwelling regions of southern Taiwan Strait(July, 2004), the entrance of Pearl River(Feb, 2004), the continental shelf along northern South China Sea(Feb, 2004 and July, 2004), and Xiamen Bay (Mar, 2003; May, 2003; Aug, 2003; Dec, 2003; Feb, 2004; May, 2004; Sept, 2004). Main conclusions are as the following : The southern Taiwan Strait, Indicated by diagnostic pigments, ultraphytoplankton groups responded to upwelling events by different distribution patterns. Most significant changes on vertical distribution were that the proportion of Cyanobacteria to total CHLA biomass decreased with depth, while Bacillariophyta, Prasinophyceae or Haptophyta increased with depth . Most of groups were significantly positive correlated to nutrients, suggesting that those groups are likely to be stimulated by nutrients coupled by upwelling,while Cyanobacteria and Prochlorophyta were negative correlated to nutrients.Four 18S rDNA libraries for eukaryotic ultraplankton in the southern Taiwan Strait were constructed. Sequences which were similar to NA and Dinophyceae were very abundant. Certain sequences which were similar to smallest eukaryote, Ostreococcus sp., were an important component in screened clones. Clustering and NMDS analysis revealed that vertical variations among most stations were lower than that between stations. Amounts of OTUs provided indicators for different water masses, such as upwelling.Xiamen Bay Indicated by diagnostic pigments, Bacillariophyta, Prasinophyceae, Cryptophyta and Chlorophyceae were dominant groups of ultraphytoplankton, while Prochlorophyta was not detected all time. Community structure was kept stable in same cruise, however, seasonal variations were prominent. Average CHLA concentration in February of 2004 was lowest, with community structure dominated by Bacillariophyta, Cryptophyta and Prasinophyceae. The highest CHLA concentration appeared in August of 2003, while Bacillariophyta were only dominating groups. In cold season, temperature and salinity determined the distributions of ultraphytoplanktons, while in warm season, Prasinophyceae were更多还原