Abundance and composition of airborne archaea during springtime mixed dust and haze periods in Beijing, China.

Archaea have an important role in the elemental biogeochemical cycle and human health. However, characteristics of airborne archaea affected by anthropogenic and natural processes are unclear. In this study, we investigated the abundance, structures, influencing factors and assembly processes of the archaeal communities in the air samples collected from Beijing in springtime using quantitative polymerase chain reaction (qPCR), high-throughput sequencing technology and statistical analysis. The concentrations of airborne archaea ranged from 10 to 10 copies m (455 ± 211 copies m), accounting for 0.67% of the total prokaryote (sum of archaea and bacteria). An increase in airborne archaea was seen when the air quality shifted from clean to slightly polluted conditions. Sandstorm dust imported a large number of archaea to the local atmosphere. Euryarchaeota, Thaumarchaeota and Crenarchaeota were the dominant phyla, revealing the primary role of soil in releasing archaea to the ambient environment. Dispersal-related neutral processes play an important role in shaping the structure of airborne archaeal assembly. Of all phyla, methanogenic Euryarchaeota were most abundant in the air parcels come from the south of Beijing. Air masses from the west of Beijing, which brought sandstorm to Beijing, carried large amounts of ammonia oxidizing archaea Nitrososphaera. The results demonstrate the importance of air mass sources and local weather conditions in shaping the local airborne archaea community.