Researchers have recently found evidence of salty groundwater in Antarctica's Dry Valleys, which provides strong support for the idea that Mars, an environment that resembles Antarctic, may have similar aquifers beneath its surface that could support microscopic life.
Using a novel, helicopter-borne sensor to penetrate below the surface of large swathes of terrain, a team of researchers supported by the National Science Foundation, or NSF, has gathered compelling evidence that beneath the Antarctica ice-free McMurdo Dry Valleys lays a salty aquifer that might support previously unknown microbial ecosystems and retain evidence of ancient climate change.
The team, which includes LSU hydrogeologist Peter Doran and researchers from the University of Tennessee; University of California-Santa Cruz; Dartmouth College; University of Illinois at Chicago; University of Wisconsin; Aarhus University in Denmark; and Sorbonne Universites, UPMC University in France, found that brines, or salty water, form extensive aquifers below glaciers, lakes and within permanently frozen soils.
In addition to providing answers about the biological adaptations of previously unknown ecosystems that persist in the extreme cold and dark of the Antarctic winter, the new information could also help scientists understand whether similar conditions might exist elsewhere in the solar system, specifically beneath the surface of Mars, which has many similarities to the dry valleys.
The team also found evidence that brines flow towards the Antarctic coast from roughly 11 miles inland, eventually discharging into the Southern Ocean. It is possible that nutrients from microbial weathering in these deep brines are released, effecting near-shore biological productivity.
However, the vast majority of Antarctica's coastal margins remain unexplored. This new survey highlights the importance of these sensitive interfaces.
The researchers used a transient electromagnetic AEM sensor called SkyTEM, mounted to a helicopter, to produce extensive imagery of the subsurface of the coldest, driest desert on our planet, the McMurdo Dry Valleys. Using a helicopter to make the observations allowed large areas of rugged terrain to be efficiently surveyed.
The results shed new light on the history and evolution of the dry valley landscape, which, uniquely in the Antarctic was ice-free and which during the height of the southern summer has free-flowing rivers and streams. The dry valleys are also home to briny lakes at the surface and beneath at least one of the glaciers that intrude into the Valleys.
The AEM team believes that the newly discovered brines harbor similar microbial communities persisting in the deep, cold dark aquifers. AEM instrumentation lead Esben Auken has flown the sensor all over the world, but this was the first time they tackled Antarctica.
The study is published in the journal Nature Communications.
