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The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols because the transported microorganisms are thought to influence the downwind ecosystems in Korea and Japan. We have analyzed bioaerosol samples collected at 10 and 800 m above the ground within the KOSA source area, Dunhuang City, China. The samples were studied by epifluorescent microscopy, revealing the presence of bacterial cells attached to mineral particles. The microorganisms in the bioaerosol samples were able to grow in media containing up to 20% NaCl, suggesting that bacteria tolerant to high salinities remain viable in the atmosphere. Phylogenetic analysis using 16S rDNA sequences revealed that halobacterial communities in the bioaerosol samples collected at both 10 and 800 m above the ground comprised a few bacterial species related to Bacillus pumilus and Staphylococcus spp. The active mixing processes of the boundary layer presumably transports viable halotolerant bacteria into the free atmosphere, where the long-range atmospheric transport of desert dust is frequently observed.

[1] Enhanced BrO and ClO in the boundary layer associated with ozone destruction have been observed over salt lakes, as well as in the polar boundary layer. Volcanic plumes are a major natural source of atmospheric trace gases, influencing the tropospheric and stratospheric trace gas budgets. Though a variety of volcanic gases have been investigated and BrO was found, there is still little information on other halogen oxides (e.g. ClO) in volcanic plumes and the effects on atmospheric ozone. The current belief that volcanic plumes contain ClO has not been quantified to date. Here we report the successful remote measurement of significant amounts of ClO (as well as BrO and SO 2 ) in a volcanic plume from the Sakurajima volcano in Japan, using ground-based multi-axis differential optical absorption spectroscopy during May 2004. Additionally halogen-catalyzed local surface ozone depletion was observed in the vicinity of the volcano. Citation: Lee, C.,

Long-range transport of atmospheric microbiota with Asian dust (Kosa) particles is of great concern in Northeast Asia in view of the health effect of Kosa particles on human being, disturbance of ecosystems caused through invasion of new microbe, contribution of microorganisms to biogeochemical cycle on global/regional scales, and others. Information on atmospheric microbes over the desert areas has been desired for a long time. Detection of atmospheric microbiota on the desert regions, on the base of balloon-borne measurements, has been made at Dunhuang, China (40°00′ N, 94°30′ E; east end of Taklamakan desert) in the summer of 2007. The measurements showed that microbiota mixed internally with Kosa particles were frequently floating from the ground to about 2-km heights (above sea level), and possible long-range transport of atmospheric microbiota with dust particles taking local circulations is strongly suggested, causing active mixing of atmospheric dust over the Taklamakan desert from the ground to the free troposphere where westerly jet dominates (Iwasaka et al. in J Geophys Res 108:8652, 2003a, J Geophys Res 108:8644, b). The concentration of the mixed particles of Kosa and microbiota having a size larger than about 1 μm in diameter is estimated to be about 1 particle/ cm 3 at those heights on the basis of measurements of particle concentration with an optical particle counter and analysis of particles having fluorescence light due to dye of DAPI (4′6-diamidino-2 phenylindole) with an epifluorescence microscope. The mixing situation of microbiota and Kosa particles is the important factor controlling atmospheric lifetime of floating microbiota, since the mixing state certainly can protect microbiota from stressful environments [dryness, solar ultraviolet (UV) radiation, low temperature] in the atmosphere, and therefore, it is useful to discuss the data of the first description of microbiota in the atmosphere on the Taklamakan desert.Keywords Dust particle . Microbiota (microorganism) . Desert areas in China . Balloon-borne measurement .

Aeolian dust is emerging as a significant vehicle for long‐range transport of microorganisms. Nonetheless, many factors relating to this highly influential dispersal mechanisms remain unresolved, including the variation in dispersal bacterial communities during stochastic desert dust events, and the effect of aeolian transit over continental and oceanic surfaces to these communities. Here we report a temporal study that encompassed multiple dust events to elucidate 16S rRNA gene‐defined changes in airborne bacterial communities at a continental‐peninsula site (Yongin, central South Korea) and a downwind offshore island site (Yonago, Honshu Island, Japan) both lying along the trajectory for dust event transport. Aerosol collected on nondust days at both sites generally reflected local origin from freshwater, marine, plant, and animal sources. At both sites, the relative abundance of spore‐forming bacteria (Bacillaceae) and organic‐aggregating bacteria (Cytophagaceae) was positively correlated with the mineral particle. Actinobacteria increased in relative abundance at the continental‐peninsula site during dust events, while marine bacterial signatures (mainly Alphaproteobacteria) were more prevalent in island site after dust events dissipated upon Japanese Sea. Overall, dust events increased the richness of airborne bacteria communities originating from inland desert and other area during early spring and are associated with more variations in airborne bacteria in the island site than the continental‐peninsula site. Airborne desert dust is likely a significant transport vehicle for bacteria. The transit of air masses over continental and marine surfaces is selective for some taxa which can be transported to distant sinks with potential impacts toward ecosystems and public health.