Ancient Antarctic microbes isolated for millennia may provide clues to alien life

The findings shed light on the extreme limits at which life can live not just on Earth, but possibly alien worlds, scientists added.

Christian H. Fritsen, DRI Research Professor, and Clinton Davis DRI graduate student
This image shows a scanning electron micrograph of very small (about 0.2 micron) and numerous bacterial cells found inhabiting icy brine channels in Antarctica's Lake Vida, which lies in the Victoria Valley, one of the northernmost of the Antarctic dry valleys.

Beneath the icy surface of a buried Antarctic lake, in super-salty water devoid of light and oxygen that is also cold enough to freeze seawater, researchers have now discovered that a diverse community of bacteria has survived for millennia.

The findings shed light on the extreme limits at which life can live not just on Earth, but possibly alien worlds, scientists added.

Researchers analyzed Lake Vida, which lies encapsulated within ice at least 60 feet (18 meters) beneath Antarctica's surface. Past studies revealed the brine in the lake has been isolated from the surface for at least 2,800 years.

"That ice is so thick, nothing from the outside can get down to the water naturally,"researcher Peter Doran, an earth scientist at the University of Illinois at Chicago, said from a research outpost on Antarctica. [Strangest Places Where Life Is Found on Earth]

To examine the brine, the researchers used drills and heated pipes to delve downward. To avoid contaminating this isolated ecosystem, researchers set up a "clean room" on top of the hole, wearing the type of white suits used in electronics and germ labs to keep conditions as sterile and free of contamination as possible.

"Doing all this in the cold of Antarctica is pretty tough," Doran said.

Life finds a way

The brine ranges from yellow to orange in color due to iron-laced compounds within it. The investigators found the temperature of the water was about 8 degrees Fahrenheit (minus 13 degrees Celsius) — its saltiness, about five to six times greater than average ocean water, keeps it from freezing like freshwater or seawater would. It is also completely depleted of oxygen and mildly acidic.

But despite the tough set of conditions, the researchers found the diverse and thriving community of microbes in the brine.

"What's most surprising is that there's anything living down there — it's a pretty harsh environment for life to take hold," Doran told OurAmazingPlanet. "There's a mantra that goes, 'wherever on Earth you find water, you find life,' and this is another one of those examples."

The brine had very high levels of carbon-based compounds, the building blocks of life. It also possessed high levels of chemicals that generally react with each other, such as nitrous oxide and molecular hydrogen, suggesting they were being regularly replenished — a surprising discovery, given how the lake was isolated for millennia from any obvious external sources of energy to help create them.

The overall chemistry of this brine suggests that chemical reactions between the water and the underlying sediment generated the reactive chemicals seen in the brine. The molecular hydrogen seen in the brine might serve as a fuel source to help support its microbial life, researchers added.

Alien implications

Similar habitats may exist on icy alien worlds, researchers said.

"By seeing what the boundaries of life are on Earth, that helps us when we go out and look for examples elsewhere," Doran said. "Years ago, we never would have thought to look for life in the sub-surface of Mars, and now we have examples on Earth that things can live down there."

Future research can explore Lake Vida's depth. "We'd like to collect samples of the bottom sediments down there, which can help us figure out this lake's history," Doran said. "When did it form? Was it always like this?"

Other teams of scientists are also drilling into other buried Antarctic lakes in search of signs of life that has been cut off from the world for millennia.

Doran, Alison Murray and their colleagues detailed their findings online Nov. 26 in the journal Proceedings of the National Academy of Sciences.

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to Ancient Antarctic microbes isolated for millennia may provide clues to alien life
Read this article in
https://www.csmonitor.com/Science/2012/1127/Ancient-Antarctic-microbes-isolated-for-millennia-may-provide-clues-to-alien-life
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe