Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Unlikely life thriving at Antarctica's Blood Falls

21.04.2009
An unmapped reservoir of briny liquid chemically similar to sea water, but hidden under an inland Antarctic glacier, appears to support microbial life in a cold, dark, oxygen-poor environment – a most unexpected setting to be teeming with life.

The McMurdo Dry Valleys of Antarctica are devoid of animals and complex plants and scientists consider them to be one of the Earth's most extreme deserts. The Valleys receive, on average, only 10 cm (3.93 inches) of snow each year.

Despite the lack of precipitation, during the Antarctic summer, temperatures rise just enough for glaciers protruding into the valleys to begin melting. The meltwater forms streams that enter lakes covered by ice that is two-to-three-stories thick.

Even less forgiving are the conditions found below the Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet in the otherwise ice-free Dry Valleys. The lack of light beneath the glacier makes the process of photosynthesis improbable, causing researchers to wonder how organisms found below the glacier could survive.

The research, which appears in the April 17 issue of Science, suggests that over the past 1.5 million years the microbes adapted to manipulate sulfur and iron compounds to survive. In place of photosynthesis, the microbes converted Fe(III) to Fe(II) to create food and energy.

The study was led by Jill Mikucki, a National Science Foundation-funded researcher at Dartmouth College. Mikucki and a team of researchers based their analysis on samples taken at the ominously, but aptly named Blood Falls, a water-fall-like feature at the edge of the glacier that flows irregularly, but often has a strikingly bright red appearance in stark contrast to the icy background.

The key piece of data supporting the hypothesis that the microbes were in fact surviving by turning Fe(III) to Fe(II) came from samples analyzed by Ariel Anbar, one of the authors of the study and an associate professor at Arizona State University, and researchers in his group, using instruments in the W. M. Keck Laboratory for Environmental Biogeochemistry at ASU.

"We found that the isotopes of Fe(II) in the brines are shifted in a way that is consistent with this microbial process," said Anbar, who holds joint appointments in the School of Earth and Space Exploration and the Department of Chemistry and Biochemistry in the College of Liberal Arts and Sciences.

Even the earliest explorers noted the massive red stain at the snout of the glacier and speculated as to what may have caused it. Some guessed that red alga was responsible for the bright color. "In fact, the red color is a result of all that Fe(II) produced by bacteria," said Anbar. "When the Fe(II)-rich water reaches the surface, the Fe(II) reacts with oxygen in the air to make Fe(III) compounds that are sort of like rust. That's the source of the red color."

The microbes are remarkably similar in nature to species found in marine environments, leading to the conclusion that the populations under the glacier are the remnants of a larger population of microbes that once occupied a fjord or sea that received sunlight. Many of these marine lineages likely declined, while others adapted to the changing conditions when the Taylor Glacier advanced, sealing off the system under a thick ice cap.

In the paper, however, Mikucki and her colleagues argue that the creatures that survive under the Taylor Glacier are both far more exotic and far more adaptable than the early explorers thought.

Because the outflow from the glacier follows no clear pattern, it took a number of years to obtain the samples needed to conduct an analysis. Finally Mikucki obtained a sample of an extremely salty and clear liquid for analysis.

"When I started running the chemical analysis on it, there was no oxygen," she said. "That was when this got really interesting; it was a real 'eureka' moment."

Further genetic analysis suggests that of the relatively small numbers of microorganisms found in the brine, "the majority of these organisms are from marine lineages," she said.

In other words, microorganisms more similar to those found in an ocean than on land, but capable of surviving without the food and light sources available in the open ocean.

"The salts associated with these features are marine salts, and given the history of marine water in the dry valleys, it made sense that subglacial microbial communities might retain some of their marine heritage," she added.

This led to the conclusion that the ancestors of the microbes beneath the Taylor Glacier probably lived in the ocean many millions of years ago. When the floor of the Valleys arose more than 1.5 million years ago, a pool of seawater from the fjord that penetrated the area was trapped. The pool was eventually capped by the flow of the glacier.

The briny pond, whatever its size "is a unique sort of time capsule from a period in Earth's history," Mikucki said. "I don't know of another environment quite like this on Earth."

Life below the Taylor Glacier may help scientist address questions about life on "Snowball Earth", the period of geological time when large ice sheets covered the Earth's surface. But it's also a rich laboratory for studying life in other hostile environments, including the subglacial lakes of Antarctica and perhaps even on other icy planets in the solar system such as below the Martian ice caps or in the ice-covered oceans of Jupiter's moon Europa.

Nikki Staab | EurekAlert!
Further information:
http://www.asu.edu

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>