Phylogenetic Diversity of Atmospheric Bacterial Communities in Korea

Transportation of microorganisms through the atmosphere is an important factor in shaping the phylogenetic structure of microbial communities over geographical scale. This concept became a major topic for biogeography in the various environments other than the atmosphere and microbial ecological studies investigating the phylogenetic diversity of the atmospheric bacterial community were emerged. The basic idea of this study is that the phylogenetic diversity of the bacterial community moving through the atmosphere is affected by the chemical properties of aerosol particles. To target the long-distance transported microorganisms, aerosol particles of diameter ≤ 2.5μm were collected. Total of 15 samples were collected and its chemical properties (inorganic ion, elemental carbon, and organic carbon concentration) were analyzed. Using high-throughput sequencing analysis targeting bacterial 16S rRNA gene, it was observed that the bacterial phyla Proteobacteria, Bacteroidetes, and Firmicutes were consistently predominant in the aerosol samples. To precisely compare the phylogenetic diversities of the samples, cluster analysis was conducted using relative abundance of genus-level bacterial. Bacterial communities were divided into three clusters. Nitrate of cluster-1 and -2 were less than that of cluster-3 indicated that the bacterial communities and aerosol particles in cluster-3 transported through long-distance. This inference was also supported by the routes calculated using backward trajectory analysis. The concentration of chloride, ammonium, and organic carbon of the cluster-3 were also higher than cluster-1 and -2. It is suggested that the dissimilarity in the phylogenetic diversity of bacterial community of cluster-3 was derived from the difference of chemical properties, in turn, the source of aerosol and routes which the aerosol passed through might be the factor for determining the atmospheric bacterial community structure. To clearly elucidate transporting distance, however, analysis of meteorological data will be required. Since the microbial and chemical data used in this study were obtained during the short period of time so the seasonal data will be analyzed to clarify the relationship of environmental factors with phylogenetic diversity of atmospheric bacteria.