Microbiome analysis of aquatic microbial communities of the urban water systems in Bandar Sunway, Malaysia

In this study, water from nine sites from the lake and river in Bandar Sunway was characterized (from three independent sampling periods), and paired with microbial analysis to reflect the extent of the impact of urbanization on water systems in Bandar Sunway. Microbial communities were characterized using Illumina MiSeq with amplifications of V3-V4 and V9 hyper-variable region of 16S and 18S rRNA genes, respectively. The 16S rRNA analysis revealed Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes as the dominant prokaryotic phyla, while 18S rRNA analysis revealed that eukaryotic communities are predominantly of the SAR clade and Opisthokonta. The abundance of Pseudomonas and Flavobacterium in all sites suggested possible presence of pathogen in the urban water systems. This correlates to the most probable number (MPN) values of more than 1600 per 100 mL derived from all sites. The abundance of Cyanobacteria suggests possible toxic blooming in Kelana Jaya lake. Observations indicated that urbanization may have impacted the microbial communities as transient communities (clinical, waterborne and opportunistic pathogens) may co-exist with common indigenous aquatic communities (Cyanobacteria). The alpha diversity analysis indicated that the core microbial community structure is not affected by the different sampling periods. The beta diversity analysis showed that the overall microbial community is similar between sites. This study suggested that while urbanization in Bandar Sunway may have no significant impact on diversity of microbial communities, the changes to the abundance of microbial phyla are detected along the water systems. This is the first study utilizing 16S and 18S rRNA amplicon sequencing approach to investigate the microbial communities in the urban water system in Bandar Sunway. The results revealed the impact of rapid urbanization activities, which led to the abundance of various microbial communities along the urban water system.

本研究针对双威镇（Bandar Sunway）的湖泊与河流共9个采样点位的水体开展了表征分析，采样覆盖3次独立重复周期，并配套开展微生物组分析，以量化城市化对双威镇水系的影响程度。微生物群落的表征采用Illumina MiSeq测序平台（Illumina MiSeq），分别对16S rRNA基因的V3-V4高变区与18S rRNA基因的V9高变区进行扩增测序。16S rRNA基因测序分析显示，变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）、放线菌门（Actinobacteria）和厚壁菌门（Firmicutes）为优势原核生物门类；而18S rRNA基因测序分析则表明，真核生物群落主要隶属于SAR演化支（SAR clade）与后鞭毛生物（Opisthokonta）。所有采样点位中假单胞菌属（Pseudomonas）和黄杆菌属（Flavobacterium）的丰度较高，提示城市水系中可能存在病原体。这一结果与所有点位测得的最大可能数（most probable number, MPN）值均超过每100毫升1600个的结果相符。蓝细菌门（Cyanobacteria）的丰度较高，提示格拉那再也湖（Kelana Jaya Lake）可能存在有毒水华。观测结果表明，城市化可能已对微生物群落造成影响：临时性群落（包括临床相关、水源性及机会致病菌）可与常见的本土水生群落（如蓝细菌门）共存。α多样性（alpha diversity）分析显示，核心微生物群落结构未受不同采样周期的影响；β多样性（beta diversity）分析则表明，各采样点位的整体微生物群落结构相似。本研究表明，尽管双威镇的城市化并未对微生物群落的多样性造成显著影响，但沿水系仍可检测到微生物门类丰度的变化。本研究为首项采用16S与18S rRNA扩增子测序（amplicon sequencing）技术探究双威镇城市水系微生物群落的相关研究，结果揭示了快速城市化活动的影响——该活动使得城市水系中各类微生物群落的丰度发生显著改变。