Monday, March 10, 2008

Microbes keep fallin' on my head

I'm listening to this NPR Science Friday podcast about the role bacteria play in the formation of ice and snow. It's a really interesting case of those single celled powerhouses, the men behind the curtain of the world, doing yet another unexpected job.

Bit of background: all precipitation (rain and snow) initially forms as ice in the clouds. For ice (or any) crystals to form, there must be a seed - something for the molecules to grab on to. In the case of rain and snow, this is usually said to be simply dust particles floating in the air. Turns out, these dust particles can really only seed ice formation at lower temperatures. So how do we get rain when the clouds are warm?

A research team led by Brent Christner has found that there are air borne bacteria that secrete a protein that mimics the lattice structure of ice, making it ideal for seeding ice crystal formation and promoting more rain than we would otherwise see. Read more here.

That's neat! Tons of questions come to mind: What would the climate look like without these little guys? Would tropical rainforests exist? What is the evolutionary advantage of this effect? Can we use the bacteria or the protein for for something (I'm looking at you, Craig Venter)?

As an aside, this shows yet another case of vain human arrogance when people say we are the only species able to affect the entire climate and atmosphere globally. I don't think we could start or stop the water cycle if we put our minds to it for a hundred years!

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