AFTER spending 120,000 years buried 3 kilometres deep in the Greenland ice sheet, a tiny bacterium has been coaxed back to life. And it may resemble bugs you would expect to find in ice on other planets.
At its smallest, the rod-shaped bug is 0.5 by 0.3 micrometres 鈥� about 50 times smaller than the common microbe, Escherichia coli.
鈥淲hat鈥檚 unique is that it鈥檚 so small, and seems to survive on so few nutrients,鈥� says of Pennsylvania State University, whose team described the new species, dubbed Herminiimonas glaciei (International Journal of Systematic and Evolutionary Microbiology, ). They recovered the bug from ice cores.
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Loveland-Curtze suspects its size and extensive flagella enabled it to survive by manoeuvring through minute veins in the ice in search of sparse nutrients. 鈥淎long with the snow, you get dust, bacterial cells, fungal spores, plant spores, minerals and other organic debris,鈥� she says. The team brought the bug back to life by keeping it at 2 掳C for seven months, then at 5 掳C for four-and-a-half months, when they saw small purplish-brown colonies.
Loveland-Curtze speculates similar microbes may have evolved in the ice on other planets and moons, such as the icy poles of Mars and the ice-covered ocean on Jupiter鈥檚 moon Europa. 鈥淏ecause ice is the best medium to preserve nucleic acids, other organic compounds and cells, the potential for finding them in these environments is quite high,鈥� she says.