A long-term survey unveils strong seasonal patterns in the airborne microbiome coupled to general and regional atmospheric circulations

The airborne microbiome is a topic of high interest in ecology, biogeochemistry, environmental and human health, among other fields. Large amounts of microorganisms are continuously exchanged among ecosystems and continents through the atmosphere, with unpredictable consequences for ecosystem services and biogeochemical cycling. Using wet bioaerosols collected fortnightly over a 7-y period at a mountaintop Long-Term Ecological Research Network site, we generated the most comprehensive long-term monitoring of the airborne microbiome reported to date. We found nonrandom recurrent interannual dynamics coupled to air circulation regimes, with a complex composition of original tracked sources. We unveil the factors influencing seasonal distributions with consistent evidence regarding the recurrence of microbes with a potential forensic signature. We highlight the need for a connected global sampling network for the airborne microbiome.