Kevin's Watch

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 understand that life can thrive in a much wider range of environments than they once believed, including superheated water at the bottom of the ocean and ice caves in Greenland. That suggests that extraterrestrial life might also exist in places once thought uninhabitable.

This new identification of microbes in subglacial Lake Whillans, a 6-foot-deep, 20-square-mile (1.8 meters, 52 square kilometers) body of water kept liquid by heat from the bedrock below and friction from glaciers moving over that bedrock, just adds to the possibilities. The authors' findings, Tranter writes, "beg the question of whether microbes could eat rock beneath ice sheets on extraterrestrial bodies such as Mars."

The Lake Whillans microbes, which come from nearly 4,000 distinct species or "operational taxonomic units" (groups of species with similar characteristics), are chemoautotrophs, meaning they get their energy not from sunlight nor from other organisms that live on sunlight, but rather from minerals dissolved in the water, including nitrites, iron, and sulfur compounds.

Given their ability to exist without light or access to organic food sources, the microbes could also be a model for life on Jupiter's ice-covered moon Europa or Saturn's Enceladus. (See "The Hunt for Life Beyond Earth.")

Hashi Lebwohl wrote:
That last bit is the important part--these microbes need neither sunlight nor other organisms for food, only the minerals in the water. This finding increases the probability that similar microbes definitely exist in extraplanetary environments, we simply haven't found them yet.

Vraith wrote:

Hashi Lebwohl wrote:
That last bit is the important part--these microbes need neither sunlight nor other organisms for food, only the minerals in the water. This finding increases the probability that similar microbes definitely exist in extraplanetary environments, we simply haven't found them yet.

yea. as I'm sure I've mentioned before, I'm as close to 100% certain as doubting-I can be that there is other life out there. I'm nearly that sure that it exists right in our own solar system. We haven't found it, cuz of a mix of can't easily mechanize definitive tests for probes, haven't looked enough places, and can't [yet] send out a multi-site machine to bring back enough samples from likely places so we can do the definitive testing here.

We probably could, with current tech, build a system-covering scooper...but it would be the single most expensive things the world has ever done, and take a really, really long time to do the job.

michaelm wrote:It puts me in mind of something I saw some years ago about the bacteria that exist in the deepest parts of the ocean. If I remember correctly, they exist on the sulfur products that are exuded from rifts in the sea bed.

michaelm wrote:It puts me in mind of something I saw some years ago about the bacteria that exist in the deepest parts of the ocean. If I remember correctly, they exist on the sulfur products that are exuded from rifts in the sea bed.