The longstanding mystery surrounding Antarctica’s Blood Falls has finally been solved. The deep red falls were first discovered in Antarctica in 1911 where scientists noticed a river had stained the surrounding cliff of ice with a dark red colour. Previously, they had believed it was due to algae discolouring the water, however that hypothesis was never verified.
An Australian geologist stumbled upon the Antarctic waterfall in 1911 and put forward the theory that the “blood” was just water that had been stained by microscopic red algae.
This explanation was overturned in 2003 when researchers concluded that oxidised iron was giving the water spilling from the Taylor Glacier its rusty tinge.
They believed it was the last drops form of an ancient salt-water lake which formed 5 million years ago.
But now a study by the University of Alaska Fairbanks and Colorado College reveals that Blood Falls is flowing from a large lake which has been trapped under the ice for one million years.
They were shocked to find that the lake hadn’t frozen despite being entombed in ice for so long. This discovery confirms that the glacier has its own water system.
When Taylor Glacier was extending across the icy continent a million years ago, it trapped a small saltwater lake under countless layers of snow and ice.
The saltwater became more and more concentrated until the brine was too salty to freeze at regular temperatures.
That subglacial brine lake has been scraping iron from the underlying bedrock, giving it its signature rusty colour once it reaches the outside world. But that path to the outside had remained a mystery until now.
To understand where the brine is coming from and how it’s oozing out of the fissure in the glacier, the team used a radar method called radio-echo sounding (RES), which is commonly used for investigating glaciers.
The team moved the antennae of the RES radar across the glacier in a grid pattern, revealing a picture of what lay beneath the ice, much like the way bats use echolocation to detect their surroundings.
As it turns out, Taylor Glacier is hiding a network of crevasses where the brine is injected into the ice under immense pressure.
The team then tracked the 300-metre (985-foot) path the brine takes through these pressurised channels until it reaches the top of Blood Falls.
Their finding also finally explains how liquid water – even if it’s super-salty – can flow through an extremely cold glacier.
While it sounds counterintuitive, water releases heat as it freezes, and that heat warms the surrounding colder ice – says one of the team, glaciologist Erin Pettit.
Brine has lower freezing temperatures – and, together with the heat, it helps the movement of the liquid.
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 – explained UAF glaciologist, Erin Pettit.
The research, published in the Journal of Glaciology, could help give scientists a better understanding of the hydrological world beneath glaciers.