[The following is an exact transcript of this podcast.]
At Antarctica’s Blood Falls, the ice is stained red by ancient, iron-rich water pouring out of subglacial lakes formed millions of years ago. The cascading water is extremely saline, has almost no oxygen and no real nutrients to speak of. But that hasn’t stopped life from finding a niche. According to a report in the April 17th issue of Science, a population of microbes has called the frigid place home for millennia.
Even though carbon-based nutrients are missing, these microbes thrive in pockets of water trapped under the glacier by making do with what they have—which is lots of sulfates and iron. The microbes use iron molecules that the glacier scours from the bedrock to react with available sulfate, which lets the microbes then metabolize it into a useable form.
The report suggests this is one way life could have survived past eras when Earth was covered in ice. It also shows that life will spring up in the most unlikely places using some very clever chemistry. So when we’re looking for life on Mars, focus less on little green men and more on little red microbes.