Biologists have extracted mineral-eating microbes from a lake buried a half mile below the surface of the West Antarctic Ice Sheet, according to a new study published in Nature.

Earlier claims of similar microbes drawn from a different Antarctic lake, say the study's authors, were controversial because the samples had been contaminated—a problem eliminated in this case by especially careful drilling techniques.

"The report is a landmark for the polar sciences," writes Martyn Tranter, a geochemist at the University of Bristol, England, who was not involved in the study, in a commentary also published in Nature.

It's also a landmark in the science of astrobiology, the search for life on other worlds. In recent years, scientists have come to