Bacteria discovered 2,600 feet below Earth’s surface could thrive elsewhere in the solar system.
Scientists drilling in Lake Whillans, a remote body of water buried 2,600 feet below the West Antarctic Ice Sheet, have discovered evidence of living bacteria.
The water samples were first removed from the ice sheet at 6:20am on Monday, January 28, by the U.S. research team Whillans Ice Stream Subglacial Access Research Drilling, or WISSARD. Researchers employed a quick test to analyze their samples for potential life by injecting DNA-sensitive dye into the water, and immediately found numerous individual cells glowing green.
To confirm their results the team will next place the lake water into dishes of nutrients and food to see if anything grows, which could take weeks. If and when it does, the resulting bacteria cultures may represent a new form of life, capable of surviving and reproducing without direct access to geothermal heat or sunlight.
The announcement follows closely on the heels of an exciting discovery that microorganisms live within clouds in the troposphere. Taken together, these findings suggest that life is capable of thriving in an even broader range of environments than scientists previously thought possible, and could broaden the list of potential extraterrestrial habitats.
The microbes residing in Lake Whillans most likely live by munching on rocks bordering the lake, and have plenty of oxygen to breathe despite their location 2,600 feet beneath the Earth’s frozen surface. When water melts off the base of the ice sheet, it releases minute but sufficient amounts of oxygen, allowing the microbes to grow.
“When you melt ice, you’re liberating the air bubbles [trapped in that ice],” Mark Skidmore, a geomicrobiologist at Montana State University and WISSARD team member told Discover Magazine. “That’s 20 percent oxygen,” he continued. “It’s being supplied to the bed of the glacier.”
Researchers hypothesize that the subterranean bacteria are engaged in a process called weathering, in which microbes use oxygen to process iron and sulfur in the rocks around them, similar to how animals use oxygen to burn sugars and fats for energy. The sulfuric acid produced as a byproduct of this activity would likely dissolve other minerals in the lake, liberating sodium, calcium, potassium, and other materials which might prove helpful to the bacteria.
Weathering is responsible for naturally deconstructing billions of tons of minerals across our planet’s surface each year, and this recent discovery suggests that the same process may be hard at work underneath the colossal ice sheets spanning Greenland and Antarctica.
“The fact that we see high concentrations is suggestive that there’s some interesting water-rock-microbe interaction that’s going on,” Andrew Mitchell, a microbial geochemist from Aberystwyth University in the UK currently working at Lake Whillans, told Discover Magazine.
The U.S. team is joined by similar groups from Russia and Britain, all drilling into lakes trapped beneath glaciers. The Russian team is drilling into Lake Vostok and recently obtained their first samples of liquid water, which at first they thought to contain life, but soon realized simply held microbes left over from kerosene used to drill beneath the ice. The British team is tapping into Lake Ellsworth, but has been forced to abandon drilling efforts after numerous setbacks.
Both the Lake Whillans discovery and the atmospheric microbe study are particularly interesting in that they involve life forms capable of thriving in conditions other than liquid surface water, an environment previously believed to be required for the development and sustenance of life. Jupiter’s moon Europa, and Saturn’s Enceladus are both believed to contain subsurface oceans of water, which could potentially play host to similarly resilient life forms.
Interested in how the research team prepared to drill beneath the Antarctic ice? Check out the following video: