Aerial transport of bacteria by dust plumes in the Eastern Mediterranean revealed by complementary rRNA/rRNA-gene sequencing

Processes influencing the transport of airborne bacterial communities in the atmosphere are poorly understood. Here, we report comprehensive and quantitative evidence of the key factors influencing the transport of airborne bacterial communities by dust plumes in the Eastern Mediterranean. We extracted DNA and RNA from size-resolved aerosols sampled from air masses of different origins, followed by qPCR and high-throughput amplicon sequencing of 16 S ribosomal RNA gene and transcripts. We find that airborne bacterial community composition varied with air mass origin and particle size. Bacterial abundance, alpha diversity and species richness were higher in terrestrially influenced air masses than in marine-influenced air masses and higher in the coarse particle fraction (3.0 to 10.0 mu m) than in the fine fraction (0.49 to 1.5 mu m). This suggests that airborne bacteria mainly were associated with dust particles or transported as cell aggregates. High abundances of rRNA from human, animal and plant pathogen taxa indicate potential ecological impacts of atmospheric bacterial transport. High bacterial community abundance and diversity are associated with coarser particulate aerosols and air masses of terrestrial rather than marine origin, according to DNA and RNA analysis of dust aerosols sampled in Rehovot, Israel.

Automated summary

This study provides comprehensive and quantitative evidence regarding the factors influencing the transport of airborne bacterial communities in dust plumes. The composition of airborne bacterial communities varied with the origin of air masses and particle size. Bacterial abundance and diversity were higher in terrestrial air masses and coarser particles, indicating a potential ecological impact of atmospheric bacterial transport.