|Image by Alicia Neal (click to enlarge)|
Sure, when as a child you looked at them all you saw in your imagination were bunny rabbits and the like, but it turns out that, in spite of the harsh environment, clouds are teeming with life.
Because of the altitude, along with the extremely cold temperatures, ultraviolet rays break down the water into toxic compounds are very acidic and contain toxins such as hydrogen peroxide. However, as Ars Technica reports:
[I]t was clear that the bacteria were breaking down a significant amount of the hydrogen peroxide themselves. This is likely a kind of coping mechanism—cells chemically stressed in this way produce an enzyme that helps neutralize oxidants like hydrogen peroxide and hydroxyl radicals.Life is pretty amazing, isn't it? They just keep finding it everywhere they look, even in some of the harshest environments. I wonder what the Mars rovers will eventually show? Odds seem increasingly tilted towards something.
Organic compounds also appear in these droplets, but the bacteria turned out to be the dominant factor behind their breakdown. For most of these chemicals, the presence of ultraviolet light (and, thus, hydroxyl radicals) was irrelevant to their stability. They only declined when there were bacteria around to munch on them. What’s more, hydrogen peroxide and hydroxyl radicals didn’t slow them down one bit.
So then, it’s likely that bacteria really are active in clouds. And they’re not just bit players—they have a significant effect on the chemistry of cloud water. They’re controlling the concentration of hydroxyl radicals and forming particles that could be future condensation nuclei (making clouds that would be more reflective and less likely to generate precipitation). In order to fully understand the behavior of clouds, researchers are going to have to pay attention to the vagabond microbes eking out a living at 5,000 feet.