南海三沙永乐龙洞古菌群落结构与多样性特征

海洋蓝洞作为一种独特的海洋地貌单元,洞内的生物群落结构与生态系统特征一直是国内外同行学者关注的热点问题之一。南海三沙永乐龙洞是世界上最深的海洋蓝洞(300m),其独特的生态特征更为引入瞩目。本研究以古菌16S rRNA基因序列为目标,采用Illumina高通量测序技术对西沙永乐龙洞内水体与沉积物中的古菌群落结构进行了研究。结果表明,本研究所获得的古菌类群可归为4门、21纲、29目、42科、45属,广古菌和奇古菌是丰度最高的两种古菌。龙洞内表层水体中古菌群落多样性与洞外水体相差不大,但随深度增加,洞内古菌群落多样性显著降低,深水层古菌群落结构与浅水层差异显著。龙洞内沉积物中的古菌生存环境与水体差异巨大,为大量特殊物种提供了生存空间。侧壁沉积物中的古菌群落多样性随深度增加显著降低,而150m平台处古菌群落多样性则远高于侧壁沉积物。水温对龙洞内水体中的古菌群落结构具有显著影响(P0.01)。研究结果显示永乐龙洞古菌群落有很高的多样性,其垂向分布与洞内环境多要素的变化密切相关。本研究对认识三沙永乐龙洞内的生态系统特征有显著意义。

ARCHAEAL DIVERSITY AND COMMUNITY STRUCTURE IN THE YONGLE BLUE HOLE, XISHA, SOUTH CHINA SEA

Marine blue holes as a unique geomorphic unit, their organism community structure and ecosystem characteristics are widely interested by the peer scholars. The Yongle Blue Hole in Xisha, South China Sea is the deepest one (300m) among the blue holes in the world. We studied the community structures of archaea in the water and sediments in the hole using 16S rRNA gene-based Illumina high-throughput sequencing. The results showed that the archaea can be identified in 4 phyla, 21 classes, 29 orders, 42 families, and 45 genera. There were great differences in the living environment in the sediments and water. The hole provided a special ecological niche for the abundant archaea in the sediments. The community diversity of archaea on the sidewall of the hole decreased obviously with increase of the depth, whereas the archaeal diversity in the sediment on the 150m depth platform was much higher than those in the sidewall. The temperature affected the community structure of archaea significantly (P<0.01). This study provides valuable data for further understanding the ecosystem of the Yongle Blue Hole as well as other anchialines in the world.