Using a helicopter-borne sensor, a team of researchers has unearthed compelling evidence that beneath the Antarctica's dry valleys lies a salty aquifer that may support microbial ecosystems and retain evidence of ancient climate change.
The team found that brines or salty water form extensive aquifers below glaciers, lakes and within permanently frozen soils.
"These unfrozen materials appear to be relics of past surface ecosystems. They now provide deep subsurface habitats for microbial life despite extreme environmental conditions," said study's lead author Jill Mikucki, assistant professor of microbiology at the University of Tennessee Knoxville.
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.
Prior to this discovery, scientists considered the lakes to all be isolated from one another and the ocean.
"The new data suggests that there is a connection between the lakes and the ocean, which is very interesting and potentially a game changer in how we view the geochemistry and history of the lakes," noted hydrogeologist Peter Doran from the Louisiana State University.
Tiny pore spaces filled with hyper-saline brine staying liquid down to -15 degree Celsius may pose one of the greatest challenges to microbes.
"Our data indicates that margins of Antarctica may shelter a vast microbial habitat, in which limits of life are tested by difficult physical and chemical conditions," added Slawek Tulacyzk, glaciologist from the University of California, Santa Cruz.
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.
The dry valleys ecosystem - cold, vegetation-free and home only to microscopic animal and plant life - resembles, during the Antarctic summer, conditions on the surface on Mars.
The new information can also help scientists understand whether similar conditions might exist elsewhere in the solar system, specifically beneath the surface of Mars.
"The application of novel below-ground visualisation technologies can not only reveal hidden microbial habitats but can also provide insight on glacial dynamics and how Antarctica responds to climate change," the authors concluded.
The discovery was detailed in the open-access journal Nature Communications.
