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.

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Roundup: Karakoram, Dust and Prokaryotes

Roundup:  Karakoram, Ice Core, and Chile

 

Karakoram Glaciers in Balance

From the Journal of Glaciology: “An anomalously slight glacier mass gain during 2000 to the 2010s has recently been reported in the Karakoram region. We calculated elevation and mass change using Digital Elevation Models (DEMs) generated from KH-9 (a series of satellites) images acquired during 1973–1980… Within the Karakoram, the glacier change patterns are spatially and temporally heterogeneous. In particular, a nearly stable state in the central Karakoram (−0.04 ± 0.05 m w.e. a−1 during the period 1974–2000) implies that the Karakoram anomaly dates back to the 1970s. Combined with the previous studies, we conclude that the Karakoram glaciers as a whole were in a nearly balanced state during the 1970s to the 2010s.”

Read more about this study here.

Karakoram's glaciers were in a nearly balanced state between 1970-2010 (Source: mtzendo / Creative Commons)
Karakoram’s glaciers were in a nearly balanced state between 1970-2010 (Source: mtzendo/Creative Commons).

 

Dust in Ice Core Reflects the Last Deglaciation

From Quaternary Science Reviews: “The chemical and physical characterization of the dust record preserved in ice cores is useful for identifying of dust source regions, dust transport, dominant wind direction and storm trajectories. Here, we present a 50,000-year geochemical characterization of mineral dust entrapped in a horizontal ice core from the Taylor Glacier in East Antarctica. Strontium (Sr) and neodymium (Nd) isotopes, grain size distribution, trace and rare earth element (REE) concentrations, and inorganic ion (Cl and Na+) concentrations were measured in 38 samples, corresponding to a time interval from 46 kyr before present (BP) to present… This study provides the first high time resolution data showing variations in dust provenance to East Antarctic ice during a major climate regime shift, and we provide evidence of changes in the atmospheric transport pathways of dust following the last deglaciation.”

Read more about the findings here.

An ice core from Taylor Glacier reveals changes in dust composition during the last deglaciation (Source: Oregon State University / Creative Commons).
An ice core from Taylor Glacier reveals changes in dust composition during the last deglaciation (Source: Oregon State University/Creative Commons).

 

Prokaryotic Communities in Patagonian Lakes

From Current Microbiology: “The prokaryotic (microscopic single-celled organisms without a distinct nucleus with a membrane or other specialized organelles) abundance and diversity in three cold, oligotrophic Patagonian lakes (Témpanos, Las Torres and Mercedes) in the northern region Aysén (Chile) were compared in winter and summer…Prokaryotic abundances, numerically dominated by Bacteria, were quite similar in the three lakes, but higher in sediments than in waters, and they were also higher in summer than in winter… The prokaryotic community composition at Témpanos lake, located most northerly and closer to a glacier, greatly differed in respect to the other two lakes. In this lake was detected the highest bacterial diversity… Our results indicate that the proximity to the glacier and the seasonality shape the composition of the prokaryotic communities in these remote lakes. These results may be used as baseline information to follow the microbial community responses to potential global changes and to anthropogenic impacts.”

Read more about the results here.

Prokaryotic diversity is greatest in Témpanos lake, near a glacier (Source: Cuorogrenata / Creative Commons)
Prokaryotic diversity is greatest in Témpanos lake, near a glacier (Source: Cuorogrenata/Creative Commons).
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