This paper investigated the ecological status of bacterioplankton in the Pearl River Estuary (PRE) through processing and analysis of 16S rRNA gene sequences obtained by high-throughput sequencing and detecting the most influenced environmental factor and the ecological niche formed by it. The results indicated that salinity was the main environmental parameters affecting the Alpha and Beta diversity of bacterioplankton in the PRE. The salinity was divided into three sequential groups: low, middle, high. The bacterioplankton in the low salinity samples had relatively high genetic diversity. The community composition analysis showed that the taxonomic information of the dominant and core OTUs of bacterioplankton under total samples and salinity groups in the study area varied widely. The dominant OTU in the total samples were Proteobacteria and the core OTUs were mostly from Acidobacteria. While the low salinity’s core OTU family were mainly C111, but the middle and high salinity samples’ were OCS111 from Acidobacteria. Moreover, the core OTUs in low salinity did not overlap with the middle and high salinity’s. Cross-grouping based OTU level on salinity and co-occurrence network analysis of the bacterioplankton showed that under the subdivided salinity grouping, OTU community formed closely related and respectively independent co-network modules, and the species composition within the modules was complex. The results showed that the salinity can effectively explain the formation of complex, closely related and independent modules of bacterioplankton, and ecological niches with specific functions, in the PRE.

通过对珠江口水域进行水样的高通量测序, 获得 16S rRNA 基因序列, 分析结果表明, 盐度是影响珠江口浮游细菌Alpha和Beta多样性的主要环境参数之一, 并且低盐度样品中浮游细菌具有相对高的遗传多样性。将盐度分为低、中、高3个组, 通过群落组成分析验证表明, 该研究区域内总样本与盐度分组样本浮游细菌的优势菌和核心菌的分类学信息差异较大。总样本中优势菌是变形杆菌门, 核心菌多为酸杆菌门。低盐度组样本中核心菌主要为C111科, 中盐度和高盐度组均为OCS111科, 来自酸杆菌门。低盐度浮游细菌与中高盐度浮游细菌的核心菌物种完全不重合。对盐度进行交叉细分, 并对浮游细菌进行共发生网络分析, 结果表明, 细分的盐度分组下, 珠江口浮游细菌群落形成紧密联系且彼此独立的模块, 且模块内部物种组成关系复杂。