Characterization of Airborne Microorganisms in Asian Dust collected from Korea Peninsula.

The nature of Asian dust(AD) and its effect on the Korean peninsula are of much concern in recent years because the intensity and frequency of AD are increasing. However, little has been known about the distribution characteristics of the airborne microorganisms in AD. To address this issue, the quantities and compositions of airborne microorganisms were monitored using culture and clone collection technique. Same analysis was performed with normal atmosphere samples as a control. AD samples collected at 3 different sampling stations in Korea during the AD periods in 2005~2007 were used in this study.
In the AD sample from Suwon on April 8^th, 2006 (the day of the strongest AD storm during the monitoring period), the population densities of bacteria and fungi were 64,980, 2,240 CFUm^-3, respectively, which were 100 and 10-fold higher than those of control sample, respectively. 641 bacterial isolates from AD were identified to genus level by using 16SrRNA sequencing and both Bacillus spp. and Arthrobacter spp. were found to be dominant. However, the dominant members of bacteria from source region of AD in China were Arthrobacter spp., Nocardioides spp. and Bacillus spp. Also, 159 fungal isolates from AD were identified based on morphological characteristics. The dominant fungal members were Cladosporium spp. and Alternaria spp. DGGE fingerprinting analysis showed that the band pattern of control sample was more diverse than those of AD, which indicate that the aerosolized microorganisms in AD are restricted to special bacterial community. Firmicutes(43.4%) and Actinobacteria (69.2%) were dominant in the culture collection in AD collected from Korea and China, respectively, whereas Fimicutes was dominant in the clone collection. The results of this study indicate that the airborne microorganisms detected during AD storm in Korea are quantitatively and qualitatively different from what can be observed in control samples. Further studies investigating the effect of airborne microorganisms carried by Asian dust storms are on the way.