Water tracks in Antarctica may be similar to phenomenon on Mars
Posted April 13, 2015
There is an underground movement underway in the McMurdo Dry Valleys.
This particular movement doesn’t involve radical political parties or fringe music festivals – though the idea of super salty water moving through the shallow subsurface of continental Antarctica’s largest, ice-free area and playing a major role in its ecology may eventually shake up established orthodoxy.
In that sense, Joe Levy could be seen as a rebel leader. The thin, darkish beard and spectacles, in fact, call to mind one of those young intellectuals who helped foment rebellion in the early decades of the 20th century. Levy’s radicalism, however, has implications that are literally out of this world.
Photo Credit: Peter Rejcek
Scientists Joe Levy, left, and Jay Dickson examine a water track near Wormherder Creek in the McMurdo Dry Valleys.
A research associate at the University of Texas’ Institute for Geophysics, Levy’s ongoing study of so-called water tracks in the McMurdo Dry Valleys may prove to be the answer to an unexplained phenomenon increasingly being observed on Mars.
Levy is in the final year of a field project mapping water tracks throughout Taylor Valley, one of the main east-west arteries of the McMurdo Dry Valleys. Water tracks are moist, dark stains on the silty, rocky soil surface that mark the passage of underground streams that flow from the hills to the valley floor, where a string of ice-covered lakes are located.
The subsurface streams are caused by melt from buried ice or snowbanks – or even moisture sucked straight out of the atmosphere from thirsty salts – that flows between the frozen, concrete-hard permafrost and the surface.
[See previous article — Drawing it out: Scientists link salty soils to wet patches in the McMurdo Dry Valleys.]
Levy contends that the subsurface streams are doing far more than causing interesting streaks across the valley: They’re moving enough liquid and salts to affect both the lakes into which they eventually flow and the soil organisms along their meandering path.
“There’s a ton of water. You have to know where to look for it,” said Levy, as he set up a thermal-imaging camera on a ridge overlooking the snout of Taylor Glacier at the extreme western end of Taylor Valley. “It’s been ignored for a long time.”
Levy refers to the area below as Wormherder Creek, an informal name for an ephemeral surface stream that occurs only during times of high flow that empties into Lake Bonney. The site is used as part of an experiment with the McMurdo Dry Valleys Long Term Ecological Research (LTER) program looking at how the soil organisms and nutrients are affected from increased pulses of surface water through the region.
Levy said just as important to the soil ecology are the subsurface streams, which appear like coffee stains on the tan surface of the valley floor.
“Some of the water tracks are probably lethal to the nematodes,” he said, referring to microscopic worms that inhabit the soils. (The term wormherders refers to the scientists who study the several species of nematodes and other soil critters in the Dry Valleys.)
The thermal-imaging camera takes images like those viewed by the Rastafarian-looking alien in the Predator movies – blobs of colors that denote hot and cold spots in the landscape. The idea is to make time-lapse movies of Wormherder Creek, capturing the water tracks as they move brines through the soils on the valley floor.
“You can plug it in and let it run overnight and watch the whole hill slope warm up and cool down, which is kind of neat,” Levy explained. “We’re getting the thermal properties of all the Dry Valleys soils – wet soils, dry soils, streams, glacial deposits.”
The camera’s LCD screen shows the cool colors of Taylor Glacier contrasting sharply with the valley floor. Strangely, the feature called Blood Falls, where hypersaline water episodically flows out of the mouth of the glacier, shows up as a hotspot – a mystery the researchers tuck away in their memories to revisit at a later date.