Bacteria survive in extreme conditions in Lake Vida, Antarctica

Scanning electron micrograph of bacteria from Lake Vida, Antarctica (Image Christian H. Fritsen, Desert Research Institute, all rights reserved)
Scanning electron micrograph of bacteria from Lake Vida, Antarctica (Image Christian H. Fritsen, Desert Research Institute, all rights reserved)

A recently published study co-authored by researchers Alison Murray and Christian Fritsen from Nevada’s Desert Research Institute (DRI) has revealed the existence of bacteria that survive in Lake Vida, Antarctica, in very extreme conditions.

Lake Vida is located in the northernmost part of the McMurdo Dry Valleys, desert valleys of the McMurdo channel in the land of Queen Victoria. The average temperature is -13.5 degrees Celsius (about 8 degrees Fahrenheit) and the water can remain in a liquid state only because of its high salinity, about six times that of seawater. The lake contains no oxygen and has the highest content of nitrous oxide among natural waters on Earth.

It’s therefore an extreme environment in which you wouldn’t expect to find any life forms, instead many types of bacteria survive in those conditions without sunlight, because the lake is covered by a layer of ice nearly 20 meters thick. According to previous studies of Lake Vida made in 1996 this unique ecosystem has been isolated for over 3,000 years.

In order to study the bacteria that inhabit Lake Vida, researchers have devised a set of very strict protocols because it was necessary to avoid any contamination. During drilling and collection of water samples from the lake operations, researchers have been working under sterile tents.

One of the questions concerned the major source of energy that allows those bacteria to survive in those conditions. Geochemical analyzes suggest that chemical reactions between the brine and the iron-rich sediments underlying generate nitrous oxide and molecular hydrogen and the latter could provide part of the energy needed for the survival of the bacteria.

The research will continue, also to study the various species of bacteria found. Genetic analyzes suggest that most of them are related to types of bacteria already known but one of the types found seems very different from all the others. It’s even possible that it belongs to a new phylum and if that’s the case it would be another extraordinary discovery.

This research is important to better understand the most extreme life forms on Earth but also because it helps us understand what life forms might exist in extraterrestrial environments similar to Lake Vida. On Europa, a Jupiter’s satellite, and on Enceladus, a Saturn’s satellite, there’s liquid water under a crust of ice, it’s possible that in those areas there are microorganisms that survive in ways similar to those of Lake Vida’s bacteria.

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