Mapping Microbes


From high in the Empire State Building to deep in California’s Muir Woods, airborne microorganisms worm their way into nearly every breath we take. Yet, says microbiologist Noah Fierer, scientists know little about their diversity and distribution.

Fierer and his team, based at the University of Colorado, Boulder, started the MiASMA project (Mapping and Integrated Analysis of Microbes in the Atmosphere) last December using the latest techniques in DNA sequencing and an air-sampling instrument that attaches to a volunteer’s car. They are charting the diversity of airborne bacteria, fungi, and viruses across the United States.

Researchers now know that water vapor can collect on the surface of airborne microbes—creating clouds—and they reason that a map of microbial distribution could help scientists more accurately forecast weather patters and track climate change. MiASMA’s map may also help us understand how land use (urban, suburban, agricultural) and time of year can affect the growth and spread of airborne microbes. And discovering where and when microbes originate may help prevent human and crop-disease epidemics, Fierer says.

With the help of “citizen scientist” volunteers, the group expects to have 300 samples by this summer. Ultimately they plan to survey more than 200 rural and urban communities, including places in every state. Fierer says that, once completed, their atlas will be “the first comprehensive database of [microbes] in the outdoor air.

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Vanessa Schipani is a former editorial assistant at The American Scholar.


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