The clouds are alive as microbes fly unfriendly skies

theaucitron

On a lazy summer day, you might look for animal shapes in the clouds, but you know they’re not real. There’s nothing alive up there but the occasional flock of airline passengers, right? Well, if you’ve ever had a microbiologist friend remark that a cloud reminded them of a bacterium, they were more right than you might have realized.

In turns out that microbes commonly hitch a breezy ride into the clouds. And while some organisms are simply biding their time, awaiting a return to familiar terra firma, others are actively going about their business despite their unorthodox surroundings. That’s no small feat considering the conditions—it’s extremely cold, UV radiation is intense, and the tiny droplets of water they often find themselves inside are acidic and chemically caustic.

Yet experiments have shown that bacteria appear to be active. And that might be important for more than just the microbes themselves. Lots of chemistry goes on in that cloud water that modifies the way clouds form and behave.