中文摘要：

为了研究白令海（海盆及陆架）至楚科奇海陆架表层沉积物中多环芳烃（PAHs）降解菌的多样性，并获得新的PAHs降解菌资源。在GC—MS分析沉积物中PAHs种类和含量的基础上，以萘、菲和芘的混合物为唯一碳源和能源对表层沉积物样品进行富集，通过平板分离鉴定可培养菌株，并验证其降解能力；同时利用变性梯度凝胶电泳（DGGE）和Illumina高通量测序技术分析降解菌群结构。GC—MS测定结果表明，14个表层沉积物中PAHs总干质量介于32．99～276．97ng／g。富集菌群中共分离获得51株可培养细菌，平板纯培养、PCR—DGGE及Illumina测序结果均表明，菌群中优势的降解菌是7Lproteobacteria的Marinobacter，Pseudoalteromonas，Pseudomonas和Actinobacteria门的Dietzia菌。此外，Illumina测序结果还表明14个降解菌群在菌群结构组成上，可分为海盆区和陆架区两种类群；同时检测到一些低丰度的海洋专属PAHs降解菌，如Cyclo—clasticus，Alteromonas和Neptunomonas等。本文结果将加深对白令海及楚科奇海表层沉积物中PAHS降解菌资源与生物多样性的认识。

英文摘要：

To detect the biodiversity of polycyclic aromatic hydrocarbon （PAH）-degrading bacterium from surficial sediments of Bering Sea and Chukchi Sea in the Arctic Ocean. Sixteen kinds of US EPA-listed priority PAHs in 14 surficial sediments were quantified by GC-MS. The degrading-consortia were enriched by using PAHs as sole car- bon and energy source. Bacteria from the enriched cultures were isolated on marine agar, and followed by 16S rRNA gene identification and phylogenetic analysis. Further, their degradation ability was tested with PAHs. The bacterial community structures were further examined by PCR-DGGE and Illumina 16S rRNA V6 region high- throughput sequencing. The dry weight contents of PAHs in 14 sediments ranged from 32.99 to 276.97 ng/g. 51 isolates were obtained from the 14 consortia,and 6 isolates of them can degrade PAHs well. The results of plate cultivation,PCR-DGGE and Illumina high-throughput sequencing all indicated that Marinobacter, Pseudoaltero- monas, Pseudornonas and Dietzia were the dominant PAH-degrading bacteria in these consortia. Furthermore, the result of Illumina analysis shown 14 consortia were separated according to their sampling geographical regions and clustered into two groups： Bering Basin, Bering and Chukchi Sea Shelves. Meanwhile, a few kinds of low-abundant marine obligate PAH-degrading bacteria were detected, such as Cycloclasticus, Alteromonas and Neptunomonas. These results contributed to the knowledge about the biodiversity of PAH-degrading bacteria from the surficial sed- iments of Bering Sea and Chukchi Sea.