Blood Falls: Origins and Life in Subglacial Environments

Blood Falls sitting at the terminus of Taylor Glacier on GlacierHub
Blood Falls sitting at the terminus of Taylor Glacier, spilling its bright-red discharge onto Lake Bonney (Source: German Aerospace Center DLR/Flickr).

Amid Antarctica’s vast stretches of glittering white snow and ethereal blue glacier ice is the famous Blood Falls. Situated at the terminus of Taylor Glacier in the McMurdo Dry Valleys, Blood Falls, which is an iron-rich, hypersaline discharge, spews bold streaks of bright-red brine from within the glacier out onto the ice-covered surface of Lake Bonney.

Australian geologist Griffith Taylor was the first explorer to happen upon Blood Falls in 1911, during one of the earliest Antarctic expeditions. At the time, Taylor (incorrectly) attributed the color to the presence of red algae. The cause of this color was shrouded in mystery for nearly a century, but we now know that the iron-rich liquid turns red when it breaches the surface and oxidizes––the same process that gives iron a reddish hue when it rusts.

The discharge from Blood Falls is the subject of a new study, published in the Journal of Geophysical Research: Biogeosciences, researchers sought to discern the origin, chemical composition, and life-sustaining capabilities of this subglacial brine. Lead author W. Berry Lyons of The Ohio State University and his co-researchers determined that the brine “is of marine origin that has been extensively altered by rock-water interactions.”  

Researchers used to believe that to be that Taylor Glacier was frozen solid from the surface to its bed. But as measuring techniques have advanced over time, scientists have been able to detect huge amounts of hypersaline liquid water at temperatures that are below freezing underneath the glacier. The large quantities of salt in hypersaline water enable the water to remain in liquid form, even below zero degrees Celsius.

IceMole at Taylor Glacier on GlacierHub
Overhead view of the IceMole, as it gradually descends into Taylor Glacier, melting ice as it goes (Source: German Aerospace Center DLR/Flickr).

Seeking to expand on this recent discovery, Lyons and his co-researchers conducted the first direct sampling of brine from Taylor Glacier using the IceMole. The IceMole is an autonomous research probe that clears a path by melting the ice that surrounds it, collecting samples along the way. In this study, the researchers sent the IceMole through 17 meters of ice to reach the brine beneath Taylor Glacier.

The brine samples were analyzed to obtain information on its geochemical makeup, including ion concentrations, salinity, and other dissolved solids. Based on the observed concentrations of dissolved nitrogen, phosphorus, and carbon, the researchers concluded that Taylor Glacier’s subglacial environment has, along with high iron and sulfate concentrations, active microbiological processes––in other words, the environment could support life.

To determine the origin and evolution of Taylor Glacier’s subglacial brine, Lyons and his co-researchers pondered other studies’ conclusions in comparison to their results. They decided the most plausible explanation was that the subglacial brine came from an ancient time period when Taylor Valley was likely flooded by seawater, though they did not settle on an exact time estimate.

An aerial view of Taylor Glacier and the location of Blood Falls on GlacierHub
An aerial view of Taylor Glacier and the location of Blood Falls (Source: Wikimedia Commons).

In addition, they found that the brine’s chemical composition was much different than that of modern seawater. This suggested that as the brine was transported throughout the glacial environment over time, weathering contributed to significant alterations in the chemical composition of the water.

This study provides insights not only for subglacial environments on Earth but also potentially to other bodies within our solar system. Seven bodies, including Europa (one of Jupiter’s moons), Enceladus and Titan (two of Saturn’s moons), Pluto, and Mars are thought to harbor sub-cryospheric oceans.

Lyons and his co-researchers concluded that this subglacial brine environment likely is conducive to life. The ability of sub-cryospheric environments such as this one to support life on Earth hints at an increased possibility of finding life in similar environments elsewhere in our solar system.

Unprecedented Subglacial Lakes Discovered in Canadian Arctic

Environments with the power to unlock the secrets of other worlds have been found several hundred meters beneath the ice of the Canadian Arctic. A joint study published last month in Science Advances predicted the presence of two hypersaline subglacial lakes on either side of the east-west ice divide of the Devon Ice Cap, an ice cap located in Nunavut, Canada, known for its rugged terrain of both mountain ridges and bedrock troughs. These are not only the first subglacial lakes to be found in the Canadian Arctic but also the first hypersaline subglacial lakes reported to date, each estimated to be around 5 and 8.3 square kilometers.

A map of the Devon Ice Cap and subglacial lake locations (Source: Science Advances).

The lakes, which are described as “unprecedented” in the study, are of great interest to researchers for their unique characteristics: both are hypersaline and spatially isolated. This isolation from outside influences may reach back 120,000 years ago, when the lakes were covered by glacial ice.

The lakes could represent significant microbial habitats, which could be used as analogs to study the conditions for potential life on other planets. Specifically, the study states that these lakes could represent similar environments to the potential brine bodies within Europa’s ice shell or Martian polar ice caps.

“Because these subglacial systems are isolated for tens of thousands of years, they are excellent candidates to explore life processes in extreme conditions,” states Alexandre Anesio, a professor and researcher at the University of Bristol who studies the biogeochemistry of the cryosphere. He sees this opportunity as “one of the best ways to explore the limits of life on other planets.”

The newfound potential of these lakes came as a shock, Anja Rutishauser, one of the study’s researchers, told GlacierHub. “The original research goal was to better understand these basal conditions of Devon Ice Cap, as they largely affect ice dynamics and how ice flow might change under future climatic conditions. We expected to find subglacial water signatures in the faster-flowing marine-terminating outlet glaciers, but certainly not in the center of Devon Ice Cap.”Rutishauser added that the ice cap was expected to have ice frozen to the ground, not liquid water or entire subglacial lakes.

A UTIG research scientist operating radar instruments inside a DC-3 aircraft during a survey flight over Devon Ice Cap (Source: Anja Rutishauser).

The discovery was made when the researchers analyzed radio-echo sounding measurement data. Models further analyzed the basal ice temperature. It measured 10.5 degrees Celsius, which led to the conclusion that the hypersalinity was significantly depressing the freezing point temperature. Further, the study found that this is in “agreement with surrounding geology, situated within an evaporite-rich sediment unit containing a bedded salt sequence,” the likely source for the salt. The exact origins of the subglacial lakes and the processes that formed them remain unclear, but similar bodies can offer clues to the specifics of the Canadian lakes.

According to the study, Taylor Glacier in Antarctica contains the most comparable subglacial fluid to the Canadian lakes, with similar temperature and salinity measurements. However, it is sourced from ancient marine water and not spatially isolated. Taylor Glacier’s outflows have been found to have active microbial communities, which leads researchers to believe the same is possible in the Devon Ice Cap.

Taken from the DC-3 aircraft during transit and aerogeophysical survey flights over Canadian Arctic ice caps and glacier (Source: Anja Rutishauser).

Many subglacial lakes in Antarctica and Greenland share other similarities with the Canadian lakes, further bolstering the study’s evidence. “Almost all the effort on subglacial lake exploration is concentrated in Antarctica, but this study reveals that there are other excellent locations for subglacial lake exploration,” according to Anesio. However, he believes further exploration is no trivial task considering the engineering challenge to drill cleanly into a subglacial lake without the risk of contaminating it. “However, it is certainly worth a try,” he said.

This is precisely how the researchers plan to follow up on their unprecedented discovery. “Our long-term vision is to cleanly access these lakes in order to derive if life exists,” added Rutishauser.

For now, Rutishauser said the research team is partnering with the W. Garfield Weston Foundation this spring to perform a more detailed aerogeophysical survey over Devon Ice Cap to derive more information about the lakes, including their hydrological and geological contexts.