The newly awakened microbe Herminiimonas glaciei may contain clues to past climatic conditions on Earth - and even life on other planets.

Credit: Society for General Microbiology

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SYDNEY: A new species of bacterium, found three kilometres deep in Greenland's glacial ice, has survived 120,000 years of freezing.

Named Herminiimonas glaciei, the microbe may contain clues to past climatic conditions on Earth, said Jennifer Loveland-Curtze, an astrobiologist from Pennsylvania State University in the U.S., and lead researcher behind the discovery.

"Ultra-small microbes are found in many environments, but very few have been studied. Glacier isolates such as H. glaciei may provide insights into how cells can survive, grow and metabolise under extremely harsh glacial conditions," she said.

Novel organism

Loveland-Curtze led a team that details the discovery in the International Journal of Systematic and Evolutionary Microbiology.

By some estimates, microbial cells make up the majority of the mass of all life on Earth, playing an important role in natural processes, such as carbon cycling. Only a small fraction of bacteria have ever been studied, however. This is because most can't be grown in a lab.

"Although DNA studies of glacial samples have detected many novel organisms, only 15 new species have been officially described," Loveland-Curtze told Cosmos Online. Official description requires a rigorous laboratory analysis of a microbe's metabolism, appearance, and genetics.

Coaxed out of dormancy

The researchers suspected that bacteria trapped in glacial ice might be difficult to culture because they are in a dormant, inactive state. They tested this theory on a melted section of ice core drilled from one of Greenland's glaciers. The ice was from a depth of three kilometres, making it around 120,000 years old.

After capturing any organisms in the melted ice with an ultra-fine filter, they coaxed the bacteria back to life by incubating them in an oxygen-free solution at just above freezing – first at 2°C for seven months and then at 5°C for four and a half months.

"A brownish-purple colony, comprised of millions of identical bacterial cells, was then visible," said Loveland-Curtze. Genetic analysis suggested they had found a new species – the bacteria's purple colour and dislike of oxygen clinched the case.