Characterization of Spatiotemporal Distribution of Freshwater Bacterioplankton Community of Lake Soyang

초록

Although the microbial community of freshwater lakes distributed around the world consists of typical and cosmopolitan bacterioplankton lineages, each lake is known to have a unique microbial composition. In addition, lakes in temperate regions have the characteristic that their microbial communities vary according to environmental factors that change dynamically with water depth and season. Here, we applied 16S rRNA gene amplicon sequencing to identify the bacterioplankton community composition of Lake Soyang using samples collected monthly for 2 years. The amplicon sequencing analyses of 120 lake water samples taken from the Soyang Dam station at five water depths revealed that the bacterial community composition was influenced greatly by seasons and depths, and it was especially variable in surface waters. Overall, Actinobacteria, Bacteroidetes, and Betaproteobacteria dominated throughout the water column. The most predominant amplicon sequence variants, affiliated with Actinobacteria acI-A7 and B1, showed consistently high abundance in the whole water samples, while those of Chloroflexi, Planctomycetes (e.g., CL500-11 and CL500-3), and Nitrosomonadaceae were abundantly present only at the hypolimnion. This study shows varying patterns of the microbial community of Lake Soyang, which provides information on spatiotemporal and phylogeographic distribution of globally or endemically abundant aquatic microbial lineages. [Supported by National Research Foundation, Korea.]