干旱区生态环境知识资源中心

Microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols, because the transported microorganisms are thought to influence biological ecosystems, and human life as well as atmospheric processes in downwind areas. However, the microbial dynamics in Japan during a KOSA dust event are unclear. In this study, sequential air sampling was performed on the top of a building (10 m altitude) within the KOSA arrival area (Kanazawa City, Japan: 36.6 degrees N, 136.7 degrees E) from May 1 to May 7, 2013, when a dust event occurred. A 16S rDNA clone library prepared from air samples mainly belonged to three phyla, such as Firmicutes, Cyanobacteria, and Alpha-proteobacteria. Some clones of Firmicutes appeared specifically during the midst of a dust event, and consisted primarily of Bacillus subtilis and B. pumilus, which are known to dominantly inhabit atmospheric area in the KOSA source area (Chinese desert). The clones belonging to Cyanobacteria and Alpha-proteobacteria were mainly detected at the initial and last periods of dust events; they are relatives to marine bacterial species. Our results suggest that airborne bacterial communities on the surface of ground during a dust event are composed of terrestrial and pelagic bacterial populations, and that the dust event influences the dynamics of airborne bacterial communities on the ground surface of a downwind area.