The team used nearly 100 air samples collected as part of a previous study conducted by Colorado State University. The CSU experiment investigated the impact of biomass burning and involved studying the impacts of residential wood burning and prescribed fires on airborne fine particle concentrations in the midwestern United States.
"What we've been looking at are the numbers and the types of bacteria in the atmosphere," Fierer said. "We breathe in bacteria every minute we are outside, and some of these bugs may have potential health implications."
The researchers analyzed the bacteria's DNA in the collected air samples and compared the bacteria they found against a database of bacteria from known sources such as leaf surfaces, soil, and human, cow and dog feces. They discovered that the bacterial communities in the air were surprisingly diverse and also that, in two of the four locations, dog feces were a greater than expected source of bacteria in the atmosphere in the winter.
In the summer, airborne bacteria come from many sources including soil, dust, leafsurfaces, lakes and oceans, Bowers said. But in the winter, as leaves drop and snow covers the ground, the influence that these environments have as sources also goes down. It is during this season that the airborne communities appeared to be more influenced by dog feces than the other sources tested in the experiment, he said.
"As best as we can tell, dog feces are the only explanation for these results," Fierer said. "But we do need to do more research."'/>"/>
|Contact: Noah Fierer|
University of Colorado at Boulder