title: Continental-scale distributions of dust-associated bacteria and fungi.
abstract: It has been known for centuries that microorganisms are ubiquitous in the atmosphere, where they are capable of long-distance dispersal. Likewise, it is well-established that these airborne bacteria and fungi can have myriad effects on human health, as well as the health of plants and livestock. However, we have a limited understanding of how these airborne communities vary across different geographic regions or the factors that structure the geographic patterns of near-surface microbes across large spatial scales. We collected dust samples from the external surfaces of ∼1,200 households located across the United States to understand the continental-scale distributions of bacteria and fungi in the near-surface atmosphere. The microbial communities were highly variable in composition across the United States, but the geographic patterns could be explained by climatic and soil variables, with coastal regions of the United States sharing similar airborne microbial communities. Although people living in more urbanized areas were not found to be exposed to distinct outdoor air microbial communities compared with those living in more rural areas, our results do suggest that urbanization leads to homogenization of the airborne microbiota, with more urban communities exhibiting less continental-scale geographic variability than more rural areas. These results provide our first insight into the continental-scale distributions of airborne microbes, which is information that could be used to identify likely associations between microbial exposures in outdoor air and incidences of disease in crops, livestock, and humans.
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309;
authors.forename: Albert
authors.initials: A
authors.lastname: Barberán
authors.affiliation: Gladstone Institutes, University of California, San Francisco, CA 94158;
authors.forename: Joshua
authors.initials: J
authors.lastname: Ladau
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309; Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309;
authors.forename: Jonathan W
authors.identifier: http://orcid.org/0000-0003-3309-2709
authors.initials: JW
authors.lastname: Leff
authors.affiliation: Gladstone Institutes, University of California, San Francisco, CA 94158;
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Pollard
authors.affiliation: Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695; and.
authors.forename: Holly L
authors.initials: HL
authors.lastname: Menninger
authors.affiliation: Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695; and Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Copenhagen DK-2100, Denmark.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Dunn
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309; Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309; noah.fierer@colorado.edu.
authors.forename: Noah
authors.initials: N
authors.lastname: Fierer
mesh_terms: D000336:Aerosols; D000391:Air Microbiology; D000485:Allergens / Q000032:analysis*; D000818:Animals; D001272:Atmosphere / Q000737:chemistry; D001419:Bacteria / Q000302:isolation & purification*; D044822:Biodiversity; D002947:Cities; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D005243:Feces; D005658:Fungi / Q000302:isolation & purification*; D005843:Geography; D006801:Humans; D015999:Multivariate Analysis; D009792:Oceans and Seas; D012621:Seasons; D012867:Skin / Q000382:microbiology; D012988:Soil Microbiology; D014481:United States; D014871:Water Microbiology; D014919:Wind
chemical_list: D000336:Aerosols; D000485:Allergens; D004391:Dust
keywords: aerobiology; allergens; microbial dispersal; microbial ecology; urbanization