Weather conditions structure the taxonomic and functional diversity of the aeolian dust microbiome.

Introduction: The aeolian dust microbiome is composed of uniquely adapted microorganisms that can withstand the harsh conditions of the atmosphere. Specific microbial taxa and survival strategies have been observed in dust microbiomes from around the world, yet the environmental processes that select for microbial composition and function are poorly understood. Methods: Here we explore the taxonomic and functional diversity of the aeolian dust microbiome from sites around the Salton Sea, a hypersaline lake in Southern California, and how dust sources and weather influenced the microbiome. Dust samples were collected from four locations around the Salton Sea in the summer and fall of 2020 and 2021, and 16S (V3-V4) rRNA amplicon sequencing and shotgun metagenomic sequencing was used to characterize the aeolian dust microbiome. Results: We observed significant differences in microbial composition between sites, and we were able to identify 13 microbial genera that were members of the core dust microbiome across samples. We also found that genes involved in sporulation, UV-radiation resistance, thermal resistance, osmotic stress resistance, quorum sensing, and antibiotic resistance were shared across the aeolian dust metagenomes. Lastly, local wind conditions and estimated dust source surface categories were significant predictors of the microbial adaptations we found in the aeolian dust metagenomes. Discussion: Our results demonstrate the ability of airborne dust microorganisms to readily adapt to their harsh environment and highlight the survival mechanisms that allow them to disperse across broad distances, thus posing a potential health risk to exposed communities.