A team of researchers solved a century-old mystery involving the famous Blood Falls on Antarctica. The team, led by scientists from the University of Alaska Fairbanks and Colorado College, found new evidence linking the Blood Falls to a large source of salt water trapped under the Taylor Glacier for over 1 million years.
Australian geologist Griffith Taylor first discovered the Blood Falls in 1911. Taylor was the first geologist to explore the valley, which is why the glacier is named after him. Several theories have sparked over the years regarding the Blood Falls.
The new study, published in the Journal of Glaciology, details the brine’s 300-foot path from beneath the Taylor Glacier to the waterfall. The path remains undiscovered since the Blood Falls’ finding back in 1911.
Blood Falls mystery: A salty brine links the waterfall to the Taylor Glacier
The first theory regarding the Blood Falls’ signature red color was written soon after the discovery, and scientists believed the red color came from red algae. Back then, researchers thought that red algae were discoloring into the water, but that theory was never verified. Another theory claimed that the red falls got their color because of iron oxides. However, the new study discards previous ideas, as researchers found that a brine was responsible for the Blood Falls’ color.
The researchers found that the Blood Falls is an intermittent outflow of iron-rich brine that hosts an active microbial community. It discharges at the surface on the north side of Taylor Glacier and stains the ice red while depositing a red-orange apron of frozen brine, which settles with each brine outflow event and degrades partially in summer’s warmer periods.
The study’s lead author, Jessica Badgeley, then an undergraduate student at Colorado College, worked alongside the University of Alaska Fairbanks glaciologist Erin Pettit and her team to comprehend the unique feature. The researchers used a type of radar to detect the brine feeding the Blood Falls.
“The salts in the brine made this discovery possible by amplifying contrast with the fresh glacier ice,” shared Badgeley.
The Antarctic red falls are famous for their sporadic releases of iron-rich salty water, and the brine gives the falls its signature red color when the iron gets in contact with air. The researchers tracked the brine with radio-echo sounding, which is a radar method that uses two antennae, one to send electrical pulses and the other to receive the signals.
“We moved the antennae around the glacier in grid-like patters so that we could ‘see’ what was underneath us inside the ice, kind of like a bat uses echolocation to ‘see’ things around it,” explained study co-author Christina Carr, a doctoral student at University of Alaska Fairbanks.
Pettit added that the team made another significant discovery in the Blood Falls. They found that liquid water can persist inside a freezing glacier. Scientists previously thought that this was next to impossible, but according to Pettit, the freezing process explains how water can flow in a cold glacier.
“While it sounds counterintuitive, water releases heat as it freezes, and that heat warms the surrounding colder ice,” said Pettit.
She explained that the heat and the lower freezing temperature of salty water make fluid movement possible and that the Taylor Glacier is now the coldest known glacier to have persistently flowing water in the world.
Also, water that is saturated in salt freezes at a lower temperature than fresh water, which is why cities salt roads to prepare for a winter storm. The high pressures at the base of the glacier would also have a small impact on lowering the temperature at which water freezes.
Microbial communities in Blood Falls resemble beginning of life on Earth
According to Forbes, the Blood Falls also have a supply of microbes that can survive in extreme conditions. Theses microbial groups can live off sulfates in the water, and they develop energy via sulfate reduction. A similar process occurs when humans convert food to energy, but instead of using oxygen, the microbial groups use sulfate.
The microbial communities living in Antarctica’s extreme conditions resemble the beginning of life on Earth before oxygen was present throughout the atmosphere. These microbes provide clues as to how life could develop on other planets that lack an oxygen-based atmosphere like Earth. They also provide evidence of the ways life can adapt to extreme environments.
Pettit noted that she enlisted Badgeley as an undergraduate student to help with the overall mission of comprehending the hydrological plumbing of cold-based glaciers. She said that Badgeley’s work was a perfect example of the high level of work that undergraduate students can do when you give them the chance and a challenge and set expectations high.
Source: University of Alaska Fairbanks