Scans unlock the million-year-old secret of what lies beneath Antarctica's Blood Falls

Via wired.co.uk by Libby Pummer

Researchers have solved another piece of the puzzle of the blood-red water at a famous site in Antarctica.

The colour of the so-called Blood Falls baffled scientists when it was first discovered in 1911 and was originally thought to be the result of red algae. The sporadic release of red water was later found to be the result of the iron-rich brine turning red when making contact with the air. In particular, the chemistry of this iron-rich, brine is altered by bacteria. When the liquid oxidises at the surface, it creates the blood-red colour similar to how rust appears.

Now, new evidence has unlocked more of its secrets as researchers discover a link to a large salt water source that may have been trapped underneath Taylor Glacier for more than a million years. Around two million years ago, this glacier trapped beneath it a small body of water full of microbes. They exist without light or free oxygen and little heat. A fissure in the glacier causes this subglacial lake to flow out creating the falls.


Previous research had suggested there could be a network of large bodies of water underneath the glacier too, and in the new study, experts from the University of Alaska Fairbanks and Colorado College used a type of radar - radio-echo sounding - to track the brine feeding Blood Falls.

"We moved the antennae around the glacier in grid-like patterns so we could 'see' what was underneath us inside the ice, kind of like a bat uses echolocation to 'see' things around it," said co-author Christina Carr, a doctoral student at UAF.

These scans revealed that liquid water can exist inside an extremely cold glacier, a phenomenon which was previously considered to be almost impossible.

"While it sounds counterintuitive, water releases heat as it freezes, and that heat warms the surrounding colder ice," explained UAF glaciologist Erin Pettit. "The heat and the lower freezing temperature of salty water make liquid movement possible. Taylor Glacier is now the coldest known glacier to have persistently flowing water."

The research, published in the Journal of Glaciology, could help give scientists a better understanding of the hydrological world beneath glaciers.

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