To understand bacterial biogeography in response to the hydrographic impact of climate change derived from the Arctic glacier melting, we surveyed bacterial diversity and community composition using bacterial 16S rRNA gene metabarcoding in the seawaters of Kongsfjorden, Svalbard, during summer 2016. In the present study, bacterial biogeography in the Kongsfjorden seawaters showed distinct habitat patterns according to water mass classification and habitat transition between Atlantic and fjord surface waters. Moreover, we estimated phylogenetic diversity of bacterial communities using the net relatedness, nearest taxon, and beta nearest taxon indices. We found the influence of freshwater input from glacier melting in shaping bacterial assemblage composition through the stochastic model. We further evaluated bacterial contributions to phytoplankton-derived dimethylsulfoniopropionate (DMSP) using a quantitative PCR (qPCR) measurement with demethylation (dmdA) and cleavage (dddP) genes of two fundamentally different processes. Our qPCR results imply that bacterial DMSP degradation follows the Atlantic inflow during summer in Kongsfjorden. These findings suggest that the Atlantic inflow and glacial melting influence bacterial community composition and assembly processes and thus affect the degradation of phytoplankton-derived organic matter in an Arctic fjord.

为了了解细菌生物地理学以应对北极冰川融化引起的气候变化的水文影响，我们在 2016 年夏季使用斯瓦尔巴群岛 Kongsfjorden 海水中的细菌 16S rRNA 基因宏条形码调查了细菌多样性和群落组成。在本研究中， Kongsfjorden 海水中的细菌生物地理学根据水体分类和大西洋和峡湾地表水之间的栖息地过渡显示出不同的栖息地模式。此外，我们使用净相关性、最近分类群和 beta 最近分类群指数估计了细菌群落的系统发育多样性。我们通过随机模型发现了冰川融化的淡水输入对细菌组合组成的影响。dmdA ) 和裂解 ( dddP ) 基因的两个根本不同的过程。我们的 qPCR 结果表明细菌 DMSP 降解是在夏季在 Kongsfjorden 大西洋流入之后发生的。这些发现表明大西洋流入和冰川融化影响细菌群落组成和组装过程，从而影响北极峡湾浮游植物衍生有机物质的降解。