A saltwater lake five kilometers long was blocked by snow. The water contains bacteria that have had no contact with the world for 2,800 years. Now these bacteria have been revealed to scientists
Researchers recently discovered an extreme lake called Lake Vida, which contained 2,800-year-old bacteria blocked under 19 meters of ice. Because the body of water has been cut off from the rest of the world for thousands of years, scientists can uncover an unknown type of ecosystem.
This can serve as an example of the way in which to search for microscopic living creatures on other worlds, including Mars.
It is believed that Lake Vida is one of several lakes on the Antarctic continent that are frozen throughout the year, but research shows that this is not the case. A team of scientists from the US excavated at two points above Lake Vida, located in a frozen desert in the Antarctic basin known as McMurdo's Dry Valley.
They also used ground-penetrating radar to look for flowing water beneath the ice sheet. The water remained liquid because it is 7 times saltier than sea water and thus it was saved from freezing even at a temperature of 10 degrees Celsius - the temperature below the ice sheet. The team did not dig directly into the lake for fear of contaminating it.
Using radioactive dating, the scientists uncovered fossils they found inside the ice cores and dated them to 2,800 years old. Inside the fossils they found bacteria that managed to come back to life after being in a frozen state for all this time.
This means that despite the complete absence of light, the cold temperatures and the strong salinity, the lake itself may contain life.
John Frisco of Montana State University, one of the researchers who examined the ice cores says: "The ice cover over these lakes represents an oasis for life in an environment that was thought to be hostile. More importantly, the cold temperature preserved the DNA quite well, making them a sort of frozen museum for ancient DNA research.
The researchers can help scientists look for life in a larger lake - Vostok - the largest of 70 lakes on the White Continent, which is no less than four kilometers deep under the East Antarctic Ice Sheet. Commenting on the findings, Dr. Dominic Hodgson, an Antarctic lake researcher from the British Antarctic Survey Plant in Cambridge, says ', says that the research raises the possibility of life on Mars. "Life can be preserved in ice for thousands of years and cells can survive at low temperatures. And as soon as the conditions are right, they break out of the frozen state and start the photosynthesis process again. This is something that scientists did not imagine a few decades ago."
The researchers at Lake Vida. According to the theories, Mars has lakes under similar conditions
The search for life on Mars is currently practiced in Antarctica
Science / 2,800-year-old frozen bacteria were found in the ice above a salt lake - and brought back to life in the laboratory
Bacteria and algae that have been kept frozen for more than 2,800 years in the ice layer above an Antarctic lake have come back to life after being thawed in the laboratory, in a study that may be a "general rehearsal" for the search for life on Mars. The research done in Lake Vida will continue, funded by the American Space Agency (NASA), which wants to find out which way is best to look for signs of life in sunken pools of salt water.
Mars, the most likely candidate for finding life elsewhere in the solar system, is a planet characterized by intense cold - like Antarctica. "For this reason, studies of the way liquid water continues to exist in cold environments are relevant to the search for life," explains Christopher McKay, a planetary scientist at NASA's California Research Center.
The head of the team of researchers at Lake Vida, Peter Duran from the University of Illinois at Chicago, explains the importance of the study: "Vida shows us a new way in which ice, salt and water combine to allow liquid water habitats, suitable for sustaining life." The life that has been found so far in Lake Vida is not taken from the water but from the layer of ice that covers it, and as mentioned includes bacteria and algae. According to the dating, the bacteria are about 2,800 years old. "When we warmed them up a little - they came alive," says Duran, the lead author of the study, which was published this week by the US National Academy of Sciences.
Lake Vida, with an area of eight square kilometers, is one of the lakes in the McMurdo Dry Valleys in Antarctica. In the 90s it was discovered that under the ice layer, at a depth of 19 meters, there is a pool of liquid water, approximately seven times saltier than sea water. In 1996, the team led by Duran drilled a hole above the pond and collected samples from the ice sheet. According to Duran, the drilling was only done to a depth of 12 meters to preserve the ice cover above the surface of the ancient lake.
In the continuation of the study, the researchers intend to return to the lake, equipped with sterile instruments. In the drilling planned for 2004, they will penetrate through all 19 meters of the ice layer and take samples from the deeper ice layers - and from the salt water in the lake. The samples will be cultured to check if they contain living organisms; According to the estimate, if bacteria are found there, they will be even older than those found in the latest research.
The future expedition will examine not only the findings - but also the working methods, which may one day be used by researchers on Mars, which is said to have lakes under the ice. "There is evidence of currents on Mars that have formed over the last million years, some kind of liquid that seeped out," Duran says. "According to one of the theories, these are pockets of salty water like the one in Lake Vida, which do not freeze because of their high salinity." Therefore, he estimates, the search for extreme life forms in Lake Vida - which are not exposed to the air or the sun and need to generate energy from chemicals in the water in order to exist - will serve as good practice for humans who will look for evidence of life on Mars in the future.
