Do microorganisms spend their entire lives in Earth's atmosphere, or are they simply found there? It doesn't seem surprising that some would find their way up there, but I have a hard time imagining how microorganisms could maintain a certain altitude. On land, they can anchor themselves to hospitable environments to breed, but in the atmosphere, how could they find one another?
Apparently they do live in the upper atmosphere. [1].
> Although many of the organisms borne aloft are likely occasional visitors to the upper troposphere, 17 types of bacteria turned up in every sample. Researchers like environmental microbiologist and co-author Kostas Konstantinidis suspect that these microbes may have evolved to survive for weeks in the sky, perhaps as a way to travel from place to place and spread their genes across the globe. "Not everybody makes it up there," he says. "It's only a few that have something unique about their cells" that allows them survive the trip.
