What Did They Find? 1.5 Million-Year-Old "Bio Lab" Unsealed by Melting Antarctica Glacier -A Galaxy Insight

No, it's not "The Thing" (that might surface later....): this blood-red stain at the snout of Taylor Glacier in the McMurdo Dry Valleys of Antarctica -one of the planet's most extreme deserts- is the by-product of unique microbes thriving in a briny 1.5 million-yea-old ocean-like reservoir beneath the glacier.

The ancient pond, whatever its size "is a unique sort of time capsule from a period in Earth's history," said Jill Mikucki, a National Science Foundation-funded researcher at Dartmouth College. . "I don't know of another environment quite like this on Earth."

Life below the Taylor Glacier may help scientist address questions about life on "Snowball Earth", the period of geological time when large ice sheets covered the Earth's surface, as well as serving as a living laboratory for studying life in other hostile environments, including the subglacial lakes of Antarctica and perhaps even on other icy planets in the solar system such as below the Martian ice caps or in the ice-covered oceans of Jupiter's moon Europa.

This unmapped reservoir of liquid chemically similar to sea water, but hidden under an inland Antarctic glacier, appears to support microbial life in a cold, dark, oxygen-poor environment – a most unexpected prehistoric biological lab teeming with life. Since their capture millennia ago, the microbes seem to have been completely isolated, hidden Under 400 meters of ice, they catch no sunlight, required for photosynthesis, and have no source of outside food, causing researchers to wonder how organisms found below the glacier could survive.

The only thing keeping the microbes alive, a new study says, is their ability to generate energy from chemical reactions with sulfur and iron.

This new microbial tresaure trove was discovered because despite the lack of precipitation, during the Antarctic summer, temperatures rise just enough for glaciers protruding into the valleys to begin melting. The meltwater forms streams that enter lakes covered by ice that is two-to-three-stories thick.

The research, which appears in the April 17 issue of Science, suggests that over the past 1.5 million years the microbes adapted to manipulate sulfur and iron compounds to survive. In place of photosynthesis, the microbes converted Fe(III) to Fe(II) to create food and energy.

The study was led by Jill Mikucki and a team of researchers based their analysis on samples taken at the aptly named Blood Falls, a water-fall-like feature at the edge of the glacier that flows irregularly, but often has a strikingly bright red appearance in stark contrast to the icy background. The iron red color is created when the Fe(II)-rich water reaches the surface, the Fe(II) reacts with oxygen in the air to make Fe(III)

The microbes are remarkably similar in nature to species found in marine environments, leading to the conclusion that the populations under the glacier are the remnants of a larger population of microbes that once occupied a fjord or sea that received sunlight. Mikucki and her colleagues argue that the creatures that survive under the Taylor Glacier are both far more exotic and far more adaptable than early explorers thought.

Mikucki and her colleagues found that the creatures that survive under the Taylor Glacier are both far more exotic and far more adaptable than early explorers thought.

Because the outflow from the glacier follows no clear pattern, it took a number of years to obtain the samples needed to conduct an analysis. Finally she obtained a sample of an extremely salty and clear liquid for analysis.

"When I started running the chemical analysis on it, there was no oxygen," she said. "That was this when got really interesting, it was a real 'eureka' moment."

Further genetic analysis suggests that of the relatively small numbers of microorganisms found in the brine, "the majority of these organisms are from marine lineages," she said.

In other words, microorganisms more similar to those found in an ocean than on land, but capable of surviving without the food and light sources available in the open ocean.

"The salts associated with these features are marine salts, and given the history of marine water in the dry valleys, it made sense that subglacial microbial communities might retain some of their marine heritage," she added.

This led to the conclusion that the ancestors of the microbes beneath the Taylor Glacier probably lived in the ocean many millions of years ago. When the floor of the Valleys arose more than 1.5 million years ago, a pool of seawater from the fjord that penetrated the area was trapped. The pool was eventually capped by the flow of the glacier.

Casey Kazan -adapted from materials provided by the NSF.

Source NSF http://onorbit.com/node/1219

http://www.eurekalert.org/pub_releases/2009-04/asu-ult041709.php