Blood Falls
Interesting facts
- The red was long blamed on red algae; iron oxide was later shown to be the real cause of the colour.
- In 2023 electron microscopes revealed that the colour comes from iron-rich nanospheres about a hundredth the size of a human red blood cell.
- Those nanospheres are not minerals because they lack a crystal structure, which is why earlier mineral-focused studies had missed them.
- Radar surveys published in 2017 traced the brine along a path of about 300 metres through pressurised channels inside the glacier to the outflow.
- Taylor Glacier is frozen to its bed, which makes it the coldest glacier known to have persistently flowing water.
- The brine stays mobile partly because freezing water releases heat, warming the surrounding ice enough for the salty liquid to keep moving.
- The brine is about 8 percent sodium chloride and rich in sulfate and ferrous iron, but contains no dissolved oxygen.
- Bacteria identified in the brine include Marinobacter, Thiomicrospira and Desulfocapsa, living on iron and sulfur chemistry instead of sunlight.
- In 2014 researchers used the IceMole, a German-designed melting probe, to sample the brine directly beneath the glacier ice.
- The 2023 team warned that rovers on Mars, which cannot carry a transmission electron microscope, could miss similar non-crystalline iron particles.
Why it is worth it
In one of the coldest and driest places on Earth, a glacier appears to bleed. At the snout of the Taylor Glacier in Antarctica, a rust-red stain spills down the white ice face and spreads across the frozen surface of West Lake Bonney. Blood Falls is not a waterfall in the usual sense but an outflow of extremely salty water that seeps out from beneath the glacier, leaving a vivid red deposit against the pale ice and the bare brown rock of the valley.
The colour comes from iron. The water is a brine trapped under the glacier, rich in dissolved iron. While it stays sealed beneath the ice, away from oxygen, the iron remains in a colourless form; once the brine reaches the surface and meets the air, the iron oxidises and turns the outflow the colour of rust. Research suggests the brine is the remnant of seawater that filled the valley around 5 million years ago, when sea levels were higher, and that it has been cut off beneath roughly 400 metres of ice for 1.5 to 2 million years. It is more than twice as salty as seawater, which keeps it liquid at around minus 7 °C.
Blood Falls has become a natural laboratory. Samples of the brine revealed at least 17 kinds of microbes living in total darkness and without oxygen, surviving by drawing on iron and sulphur compounds. Their survival in such a sealed world has made the site a reference point for research into life beneath ice. The red deposit was first noticed in 1911 by the Australian geologist Thomas Griffith Taylor, after whom the valley and glacier are named, during Robert Falcon Scott's British Antarctic Expedition. Taylor Valley itself is the southernmost of the three large McMurdo Dry Valleys in Victoria Land, an ice-free landscape of gravel, rock and frozen lakes that was first sighted by Scott's earlier Discovery expedition of 1901 to 1904.
Getting there
Blood Falls lies at the head of Taylor Valley in Victoria Land, on the western side of McMurdo Sound in Antarctica, about 100 km in a straight line from McMurdo Station and Scott Base on Ross Island. There are no permanent settlements, roads or public airports nearby; researchers working in the Dry Valleys travel by helicopter from Ross Island, which is linked by flights to Christchurch (CHC), New Zealand.
On these lists
From the encyclopaedia
Blood Falls is an outflow of an iron(III) oxide–tainted plume of saltwater, flowing from the tongue of Taylor Glacier onto the ice-covered surface of West Lake Bonney in the Taylor Valley of the McMurdo Dry Valleys in Victoria Land, East Antarctica.
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