15 Mayo 2017 15:55
The answer to the mystery lies 300 metres below the ice
In the middle of the pristine whiteness of the South Pole, an immense red stain spreads across the cliffs of Antarctica. This striking image in such an untarnished environment was first stumbled upon by explorers in 1911, who mistakenly thought that the anomalous colour of what has been dubbed Blood Falls was caused by red algae.
Although this theory was later dismissed when samples were found to contain iron oxide, the frozen depths of the impenetrable Taylor Glacier, in Victoria Land, East Antarctica, have always concealed the secret to the origins of this bizarre wonder.
At last, by using a special type of radar, a team of scientists, led by the University of Alaska Fairbanks, has discovered the route taken by the red brine 300 metres beneath the surface of the glacier. According to an article published in the Journal of Glaciology, the iron-rich flow of salty water moves through the inside of the glacier and oxidises when it exits the ice and comes in contact with the air.
Jessica Badgeley, the main author of the research, asserts that more than a million years ago, as Taylor Glacier spread out across Antarctica, it trapped a small saltwater lake under many layers of snow and ice. Despite it being considered almost impossible for liquid water to remain inside a glacier, the brine became so concentrated that it was too salty to freeze.
"While it sounds counterintuitive, water releases heat as it freezes, and that heat warms the surrounding colder ice. 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", explains glaciologist Erin Pettit.
The study also shed light on the ecology of this current, revealing that it sustains life. The water is home to highly resistant bacteria which have managed to survive being trapped in these conditions for millennia, feeding on sulfates. The ice of ‘Blood Falls’ plays host to life and flowing liquid water.