A bank of fog might seem gloomy. But that mist may carry an unexpected community of environmental helpers. Ground-dwelling clouds can house bacteria that clean the air, a new study finds.

Microbes can find air a harsh place, notes Kathleen Weathers. Temperatures can fluctuate broadly. And even in fog, there can be a high risk of drying out. A fog scientist, Weathers works at the Cary Institute of Ecosystem Studies in Millbrook, N.Y. But, she adds, fog hosts many things needed for those microbes to “make a living.” These include moisture, nutrients and comfortable temperatures.

Yet until now, scientists hadn’t known microbes could actually live there, says Weathers, who did not take part in the new work.

It took Thi Thuong Thuong Cao, a chemist who loves hiking on foggy mountainsides, to show microbes not only can live in fog, but also grow and reproduce.