A spectacular sight indeed is that of the five-story, blood red waterfall falling down slowly from the Taylor Glacier onto the white, ice-covered West Lake Bonney on the Taylor Valley in East Antarctica’s McMurdo Dry Valley. Known as the Blood Falls, this waterfall is the result of iron-rich, hyper-saline waters, with their flows originating from a sub-glacial pool overlaid by ice sheets several kilometers away from the Blood Falls. The iron-induced red color of the waters of this fall forms a striking contrast with the stark white surroundings, lending the falls its name.
The Blood Falls was discovered in 1911 by the Australian geographer, anthropologist, and global explorer, Griffith Taylor, who visited the Taylor Valley in Antarctica (named after him) during this time. From that time onward, several attempts were made by scientists to elucidate the nature of the crimson-colored waters of the falls. Originally, the color was attributed to the presence of red algae, but it was later discovered to be due to high concentrations of dissolved iron oxides instead. The scientists then further studied the origins of the waterfall and discovered that the source of the water came from a sub-glacial lake trapped beneath a quarter mile of ice. The sub-glacial lake probably had formed 5 million years ago when rising sea levels flooded Eastern Antarctica, forming salty lakes as a result. These lakes were later submerged under ice sheets, but the waters in them failed to freeze due to the high salt levels.
The Blood Falls appear to provide some real answers to significant scientific hypotheses, such as the "Snowball Earth" hypothesis. According to it and the section of scientists who believe, the Earth’s surface was once completely, or nearly completely, frozen sometime earlier than 650 million years ago, possibly during the Proterozoic Eon, to the extent that it would have been seen appearing like a snowball. However, an explanation was needed as to how the primordial living forms survived such frozen conditions. The sub-glacial lake feeding the Blood Falls could provide an important clue to this answer. It is quite possible that, like the microbiota residing in the sub-glacial source lake of the Blood Falls, sea-water below the ice-laden Earth’s surface during the massive freezing event in the Proterozoic Eon remained unfrozen, thereby supporting microbial life under the ice. The presence of microbial life in the Blood Falls could also implicate that life is possible not only under similar extreme conditions on the Earth, but also in similar environments in other planets and moons of the solar system, such as the cold planet of Mars and the large moon of Jupiter known as Europa.
Does Life Exist In Blood Falls?
An examination of the waters from the Blood Falls has indicated some unexpected results. A rare collection of autotrophic bacteria have been discovered that are able to survive the cold, anaerobic, and high salinity conditions of the sub-glacial waters found here. At least 17 different types of microbes have been discovered here, which might be utilizing the sulfate content of the water as a catalyst to respire with ferric ions. By some unknown chemical reaction not yet known by today's scientists, the by-products of this microbial respiration may somehow react with the iron to restore the sulphates to be used by the microbes over and over again.
There is a significant volume of ongoing research in Antarctica to understand the complex systems at play, including those that have been responsible for sustaining life in the dark, anaerobic conditions of the Blood Falls’ sub-glacial source lake. There remains a need to further comprehend the poorly understood sulfur and iron biochemical cycles in action in this and other Antarctic sub-glacial lakes. In December of 2014, a team of scientists and engineers used a probe called the IceMole to melt into the glacier to collect samples of the brine that feeds into the Blood Falls. Extensive studying of these and future collected samples could unlock the answers to many of the unsolved problems of the scientific world.