They have been found under miles of ice

Jun 15, 2009 07:47 GMT  ·  By
The newly found bacteria lived for the last 120,000 years some three kilometers deep under Greenland ice
   The newly found bacteria lived for the last 120,000 years some three kilometers deep under Greenland ice

In their search for life on other planets, researchers are always hindered by a single fact – they don't know what life in other planetary conditions than those of the Earth may look like. Different pressure and atmospheric surroundings may affect the development of even the most basic forms of life on exoplanets in a way we couldn't even imagine. Now, recently discovered bacteria, found three kilometers under a Greenland ice sheet, and believed to have been buried there for the last 120,000 years, with no contact with the outside world, may hold some much-needed answers.

Herminiimonas glaciei, the new microorganism, was discovered by a team of scientists from the Pennsylvania State University (Penn State), led by Dr. Jennifer Loveland-Curtze. In a report the researchers published in the latest issue of the International Journal of Systematic and Evolutionary Microbiology, they show that the bacteria are purple-brown in color and that they are very tiny in size.

Getting them back to life was a real problem. The cultures had to be incubated at two degrees Celsius for about seven months, and then at five degrees Celsius for an additional four and a half months. It was only then that the team was finally able to observe the living organisms inside the samples. The bacteria themselves are very small, about ten to 50 times more compact than E. coli. Because of their reduced dimensions, they were able to survive in the most unlikely places.

The team inferred that they managed to find shelter in the tiny water veins that existed between ice crystals in the depths of the ice sheet, as well as in microfilms of water that could be found on the surface of the same crystals. The conditions in which they survived are incredibly rough, and this is the main reason why researchers have taken such an active interest in them. They argued that bacteria such as these, together with others living in pure rock, or new hydrothermal vents at the bottom of the ocean, or inside volcanoes, made for the most potent research material on the toughness of life.

“These extremely cold environments are the best analogues of possible extraterrestrial habitats. The exceptionally low temperatures can preserve cells and nucleic acids for even millions of years. H. glaciei is one of just a handful of officially described ultra-small species and the only one so far from the Greenland ice sheet; studying these bacteria can provide insights into how cells can survive and even grow under extremely harsh conditions, such as temperatures down to -56˚C, little oxygen, low nutrients, high pressure and limited space,” the expert said.

“H. glaciei isn't a pathogen and is not harmful to humans, but it can pass through a 0.2 micron filter, which is the filter pore size commonly used in sterilization of fluids in laboratories and hospitals. If there are other ultra-small bacteria that are pathogens, then they could be present in solutions presumed to be sterile. In a clear solution very tiny cells might grow but not create the density sufficient to make the solution cloudy,” Dr. Loveland-Curtze concluded.