Scientists have long studied airborne bacteria, but they typically do so from the ground, so not much has been known about the number and diversity of floating microbes, researcher Athanasios Nenes, an atmospheric scientist at Georgia Tech, said.
To find out more, Nenes and his colleagues hitched rides on a NASA research aircraft doing atmospheric sampling before and after hurricanes in 2010, the Los Angeles Times reported.
During flights over the Caribbean and the Atlantic the researchers used filters to gather material from the surrounding atmosphere.
Of the material of a size range to be captured by the filters, bacteria accounted for 20 percent of material scientists had assumed would be just sea salt and dust.
"We were surprised," Nenes said, noting the filters were picking up fungi as well.
Researchers said they surmised the bacteria must have developed traits that allowed them to survive freezing temperatures, feed on the scarce carbon compounds in clouds and survive in an environment bathed in ultraviolet radiation from the sun.
Such microbes could conceivably collect water vapor and seed clouds, causing them to release rain, the researchers said.