Discovered in 1911, Antarctica's Blood Falls has captured the curiosity of countless scientists. The falls looked like a bleeding glacier; there were many questions about its water source and the cause of its sanguine color. As studies, samples, and theories abounded for decades, the presence of microorganisms in Blood Falls opened up a new mystery: What if these microbes held the answer to alien life on other planets?
While researchers found answers to some questions about Blood Falls, others remain: Can the falls offer a path to discovering life on a harsh planet like Mars? Or is it an anomaly only found on Earth?
In 1911, Scientists First Attributed The Red Water To Algae
Australian explorer and scientist Griffith Taylor discovered Blood Falls in 1911. Taylor found the five-story-tall crimson spout trickling from Taylor Glacier - also named after the Australian - in the McMurdo Dry Valleys of Antarctica. The blood-red phenomenon elicited interest from other scientists eager to decipher the natural mystery.
Scientists initially believed red algae in or near the glacier supplied the crimson color to the falls; however, proof surfaced in 2009 to debunk this theory. Early explorers also questioned the source of the waterfall, especially since the giant slab of ice did not melt and seemed to maintain its temperature to create the cascade from its side.
A 2009 Study Found The True Cause Of The Coloration
Dr. Jill Mikucki collected water samples from Blood Falls over a six-year timeframe. The findings resulted in a groundbreaking 2009 study revealing the source of its color. Tested samples showed low oxygen content, high salt levels, and large amounts of iron from the valley floor and walls. The results also found 17 different types of microorganisms, which suggested a rare, previously unknown ecosystem existed.
The briny liquid flowed from the glacier terminus, made contact with oxygen, and immediately turned a rusty-red color. Mikucki and her team found that the ice-entombed ecosystem's microorganisms couldn't access oxygen, so they combined sulfate with iron to approximate breathing. The water's iron levels oxidize - turning into a rusty color - when reaching the air, which provides Blood Falls's shocking color.
The Subglacial Source Lake Formed From Floods Millions Of Years Ago
The subglacial lake was a likely result of seas flooding Antarctica five million years ago, resulting in salty bodies of water on land. Scientists estimate one-and-a-half to two million years ago, this particular lake became trapped under Taylor Glacier.
The glacier sealed the lake from sunlight, oxygen, and heat; microscopic organisms remained trapped within the water. Still, other saline lakes remained above ground after the flood, such as the frozen Lake Bonney, where Blood Falls spills its red contents during warmer months. With these discoveries, scientists began to wonder if Mars could host microscopic life beneath the surface of similar bodies of water.
Electromagnetic Mapping Pinpointed A Subglacial Lake System In 2015
In 2015 Mikucki and her team used an electromagnetic sensor attached to a helicopter to analyze the area around and under Taylor Glacier. SkyTEM - an airborne geophysical survey company - flew the contraption over the area while sending an electrical current into the ground. To map out the glacier's underground contents, the scientists extrapolated the electric current's depth before its encounter with resistance.
The resistance informed the team of at least two bodies of water with high salinity existing below Taylor Glacier's icy surface. The water was twice as salty as the ocean and stretched more than seven-and-a-half miles. These findings prompted speculation about the subglacial water's connection to the area's surface lakes; it also suggested the underground ecosystem could be more extensive than initially thought.