南极普里兹湾夏季不同层次海冰及冰下海水古菌丰度和多样性

ARCHAEAL ABUNDANCE AND DIVERSITY WITHIN DIFFERENT SECTIONS OF SUMMER SEA-ICE AND SEA WATER IN PRYDZ BAY,ANTARCTICA

为了解南极普里兹湾夏季不同层次海冰及冰下海水中古菌丰度及群落组成,利用荧光原位杂交(filter in situhybridization,FISH)技术对海冰及冰下海水样品中古菌进行定量研究,通过构建16S rRNA基因文库对不同层次海冰及冰下海水中古菌进行多样性分析,并结合环境因子进行相关性分析。荧光原位杂交结果表明,古菌的平均丰度随着海冰层次的下降呈下降趋势,初步推断可能受海冰中铵离子影响所致;16S rRNA基因文库分析结果表明,仅在海冰底部样品中检测到古菌,且全部16S rRNA基因序列为泉古菌(Crenarchaeota),与来源于北极海水、海冰中古菌16SrRNA基因序列相似性最高,属于泉古菌海洋类群I(Marine GroupⅠCrenarchaeota);冰下海水古菌多样性较高,主要归属于泉古菌Marine GroupⅠ和广古菌(Euryarchaeote)Marine GroupⅡ、Ⅲ。

To determine the abundance and diversity of archaea in Prydz Bay, Antarctica, summer sea-ice and seawater samples were collected during the 26th Chinese National Antarctic Research Expedition. Fluorescence in situ hy- bridization （FISH） was applied to determine the proportions of different archaea. Community composition was ana- lyzed by constructing a 16S rRNA gene clone library. Finally, correlation analyses were performed to assess links between physicochemical parameters and archaeal diversity and abundance within the sea-ice. The FISH found that archaea was abundant in the top section of sea-ice, with the concentration of NH4 identified as a major driver of this distribution pattern. Using 16S rRNA gene libraries, archaea were not detected in the top and middle sections of the sea-ice. Overall, the diversity of archaea in sea-ice was low; all archaeal clones obtained from the bottom section of the sea-ice were grouped into the Marine Group I Crenarchaeota, while the archaeal clones from seawater were grouped into Marine Group I Crenarchaeota, Marine Group II and III of Euryarchaeote.