If you were ever pressed to make a list of the planet’s most extreme desert regions, Antarctica probably would be one of the last places you’d look, but your list wouldn’t quite be complete without making mention of the McMurdo Dry Valleys. It’s one of the few regions in the Antarctic that remains untouched by ice throughout the year, an area almost 2,000 square miles wide with high mountains that prevent most forms of precipitation from entering, as they block off the ice that flows seaward from the East Antarctic Ice Sheet.
What’s even more surprising, if you’ve never heard of this region of mostly loose gravel, with winds traveling at speeds of up to 200 miles per hour, is that despite its harrowing low humidity, new research suggests that underneath the rock region there lies a basin filled with salty, and ice cold groundwater. This underground basin may be a tributary that connects with the surrounding lakes, linking them into one massive network, and, as has already been spotted on this strange continent, the basin likely hosts a myriad of never before seen microbial lifeforms.
These new findings were reported on Tuesday in the journal Nature Communications.
There always seemed to be something unsettling about the place. McMurdo is the home of the gloriously eerie Blood Falls, the name given to a phenomenon in which strange red ooze, resembling dried blood, which shines bright atop what is an unsettlingly desolate surface of rock. It appears as though the rocks are bleeding, which momentarily makes the place seem like something only H.P. Lovecraft could imagine for his novel At the Mountains of Madness, which describes an expedition to the Antarctic gone horribly wrong.
For a long time, many scientists had thought that it was red algae, similar to the kind found in red tides along the West Coast, that caused the coloration of this strange, bloody ooze. While iron oxide is a primary ingredient in the ooze, and gives it its vibrant color, a deeper analysis has revealed that the Blood Falls do harbor some unusual bacterial lifeforms.
Blood Falls has come from quite a distance, seeping from all the way at the end of the Taylor Glacier towards Lake Bonney.
While scientists had known that this ooze had a source, they were quite pleasantly surprised to discover the overwhelming extent contained by the valley’s briny waterways.
“I’ve been studying Blood Falls for quite some time, and it’s always been a mystery,” said the study’s lead author Jill Mikucki from the University of Tennessee. Being a microbiologist, she has had a longtime interest in the microbial ecosystems that thrive within the oozy brine.
In order to survey the area, Mikucki and her colleagues made use of an electromagnetic sensor mounted on top of a helicopter, which then tested the electrical conductivity of the ground beneath their feet. As water begins to freeze, it increases in its resistivity, meaning that it’s less conductive of electrical currents. Salty water, however, is capable of remaining in liquid form at much lower temperatures and has a very low degree of resistivity.
“We found, as expected, that there was something sourcing Blood Falls,” Mikucki said, “and we found that these brines were more widespread than previously thought. They appear to connect these surface lakes that appear separated on the ground. That means there’s the potential for a much more extensive subsurface ecosystem, which I’m pretty jazzed about.”
It is also a good possibility that this substantial amount of brine is not unique to the dry valleys, Mikucki explained. Therfore, it is likely that these subsurface ecosystems made up of extreme microbes may be interconnected to visible lakes on the surface, and perhaps they may even have interaction with the ocean.
Microbiologists call this type of bacteria extreme because those are the types of conditions in which they flourish – intense cold, salinity, or heat. A prime example of the latter is Thermus brockianus, discovered in Yellowstone National Park, where it established colonies around the geyser Old Faithful. Since then, industrialists have domesticated the bacteria which is used to take the hydrogen peroxide out of treated wood, bleaching it to make paper products. Less than a year ago, scientists working in Antarctica sampled water from one of the continent’s subglacial lakes, discovering a well adapted colony of bacteria that exists half a mile beneath the ice.
Extremeophiles aren’t unique to bacteria either. Some species of tree lichen brought to outer space have been seen to undergo photosynthesis and rapidly adapt to the sunlight cycles of other planets on an experiment aboard the International Space Station.
“It turns out that as beautiful and visceral as Blood Falls is in these valleys, it’s actually just a blip. It’s a little defect in this much more exciting feature,” she said.
Mikucki is hoping that soon the team shall be able to return and survey more extensively with the electromagnetic sensor, giving them a bigger picture of how much connection exists among the lakes of Antarctica, and therefore how often the subsurface brines come into contact with oceans along the coast. In addition to being the perfect setting for a horror or pulp adventure novel, all scientific research done in the Dry Valleys has another purpose too, as everything done by the research team does is just as practical for future space explorations as it is for learning more about Earth and the continent of Antarctica, which during the Meosozoic Era was actually a vast tropical region.
“Scientists have been using the Dry Valleys to test instruments since the Viking missions,” Mikucki said. “So how we detect the brines and access them is relevant to work on places like Mars.”
Indeed, there is already some evidence suggesting that brines may exist on Mars, responsible for some unusual, jagged features in the mountains of the red planet. It could be a likely sign that at one time, life thrived throughout the planet, in an era when its geographical features were not much different from our own. There may even be microbes on Mars already, the Tersicoccus phoenicis, which has been isolated in spacecraft assembly cleaning rooms and develops resistance to most cleaning fluids. The fact that they might be resistant to space travel raises questions about how well they may interact with alien forms of bacteria. Russian cosmonauts last summer also reported finding large numbers of sea plankton outside the windows of the International Space Station, indicating that they were able to thrive in the extreme cold of space.
If we are to discover interplanetary life in the near future, it will most likely resemble the life we have recently discovered in Antarctica. The subsurface Lake Vostok, which is currently believed to hold some extensive (and rather unusual) life forms, is also considered to be a prime example of what our technology may soon discover on Europa, the ice-and-ocean covered moon of Jupiter, or Enceladus, which may contain a frigid ocean beneath its surface. On our own planet, these types of subsurface waters are able to support only the most extreme forms of life, and some things close to life – such as large viruses that thrive on bacterial microbes alone. Elsewhere in our solar system, however, these same extreme conditions could be as supportive as planets get when it comes to hosting life.
“The subsurface is actually pretty attractive when you think about life on other planets. It’s cold and dark and has all these strikes against it, but it’s protected from the harsh environment on the surface,” Mikucki said.