Variations in the structure of airborne bacterial communities in Tsogt-Ovoo of Gobi Desert area during dust events

Asian dust events transport the airborne bacteria in Chinese desert regions as well as mineral particles and influence downwind-area varying biological ecosystems and climate changes. However, the airborne bacterial dynamics were rarely investigated in the Gobi Desert area, where dust events are high frequent. In this study, air samplings were sequentially performed at a 2-m high above the ground at the sampling site located in desert area (Tsogt-Ovoo of Gobi Desert, Mongolia: 44.2304N, 105.1700E). During the dust event days, the bacterial cells and mineral particles increased to more than ten folds of concentrations. MiSeq sequencing targeting 16S ribosomal DNA revealed that the airborne bacteria in desert area mainly belonged to the classes Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Bacilli, Alpha-, Beta- and Gamma-proteobacteria. The bacterial community structures were different between dust events and non-dust events. The air samples collected at the dust events indicated high abundance rates of Alpha-proteobacteria, which were reported to dominate on the leaf surfaces of plants or in the saline lake environments. After the dust events, the members of Firmicutes (Bacilli) and Bacteroidetes, which are known to form endospore and attach with coarse particles, respectively, increased their relative abundances in the air samples. Presumably, the bacterial compositions and diversities in atmosphere significantly vary during dust events which carry some particles from grassland (phyllo-sphere), dry-lake, as well as sand surfaces, and some bacterial populations such as Firmicutes and Bacteroidetes maintain in atmosphere for longer time.