Hardy Bacteria 
The tiny organisms known as cyanobacteria are among the hardiest creatures on Earth. They've been around for at least three-and-a-half billion years, and they can live anywhere, including the harshest deserts. That gives scientists hope that they might be found in an even harsher desert: the surface of Mars.
In fact, they might find comfortable homes beneath a substance known as rock varnish -- a thin coating found on some rocks here on Earth, and perhaps on Mars as well.
At the University of Wisconsin, planetary scientist Kim Kuhlman and graduate student Andrew Corcoran are studying rock varnish from Earth's deserts. That includes the dryest desert of all, the Atacama in Chile. As Corcoran and Kuhlman explain, they grind up the varnish and then analyze it for signs of life.
CORCORAN: There are a few things you can do with that ground-up rock varnish. One is get DNA sequences from it. I have only sequenced the bacteria, and I was able to get back 82 sequences. And a lot of that was in types of cyanobacteria. Another thing is something called FISH -- probes that will target the chromosomes inside it so you can visualize it in a microscope.
KUHLMAN: The whole goal of FISH is to say, "The cyanobacteria live here, the actinobacteria live here" -- try to figure out where in the varnish layering these critters are living.
Their work could help planners decide whether future Mars landers should target rock varnish in the search for life on the Red Planet.
Script by Damond Benningfield, Copyright 2011