A large reservoir of liquid water has been discovered by Jill Mikucki and her colleagues beneath Antarctica’s Taylor Valley. Since the only natural outlet of that reservoir, Blood Falls, contains a diverse population of microbes, the implication is that the whole reservoir may be teeming with life.
The research team used an electromagnetic sensor attached to a helicopter to measure the resistivity of the subsurface. Because liquid water has much lower resistivity than does ice, the technique allowed them to outline huge underground aquifers. Based on the remote sensing results, Mikucki and colleagues concluded that the salt content is about twice that of normal sea water, and water temperatures are at about -3 to -20 oC—still within the environmental envelope to support life.
These intriguing ground-water reservoirs—two large basins were discovered—are hidden, and are largely disconnected from surface influences. That makes them a great analog to subsurface liquid reservoirs that have existed and may still exist on Mars. They may also inform us about the possibilities of life in subsurface oceans elsewhere, such as Europa or Enceladus.
Previous modeling of the liquid water reservoir that discharges into Blood Falls supports the idea of subsurface microbial ecosystems under Taylor Valley, with a low productivity and low organic content. In order to keep the ecosystem going, a continuous supply of oxidized iron has to be present (the iron content of the discharged water is clearly visible at Blood Falls, which also gave it its name). The modeling study, conducted by a graduate student of mine, has implications for what kinds of ecosystems we might find under similar conditions on Mars, perhaps underneath a glacier or the ice-covered northern polar area.