Is a corner of Antarctica that looks like something out of a David Cronenberg movie. It is located in the desiccated valleys of McMurdo, a immense frozen desert where, from time to time, a stream of scarlet liquid suddenly bursts from the blinding whiteness of the Taylor Glacier. They are called the Blood Falls, and since their discovery in 1911 by geologist Thomas Griffith Taylor, they have been the source of centuries of scientific speculation.
The science behind blood falls
At the time of their discovery, Taylor attributed the color to the presence of red microalgae. More than a century later, scientists determined that the red was due to iron particles trapped in nanospheres along with other elements such as silicon, calcium, aluminum and sodium. They were probably produced by historic bacteria trapped underground in this area: the iron oxidizes on contact with air, giving the mixture its characteristic rusty color.
As for the presence of liquid water, it is actually hypersaline brine, which was formed about 2 million years ago when the waters of the Antarctic Ocean retreated from the valleys. The very high salinity of this brine prevents the water from freezing, which allows it to gush out periodically.
A novel discovery
With the temperature mystery solved, the question remained as to what physically caused the fluid to erupt. The answer came after collating GPS data, thermal sensors and high-resolution photos collected during the 2018 eruption. Analysis revealed that the Bloody Falls are the result of pressure changes affecting brine deposits beneath the glacier.
As the Taylor Glacier slides downstream, the mass of ice covering it compresses the subglacial channels, creating enormous pressure. When the tension becomes unbearable, the ice gives way: pressurized brine flows into the cracks and is ejected in tiny bursts. Interestingly, this slowdown acts as a hydraulic brake, temporarily slowing down the glacier’s advance. With this discovery, the mysteries of Blood Falls should finally be solved, at least for now. The impact of global warming on this intricate system in the coming decades remains unknown.
This story originally appeared on WIRED Italy and was translated from Italian.