Scientists doom planet after resurrecting 120,000-year-old bacteria.

Oh, great idea! That bacteria we know nothing about that can survive and propagate on so little? Let's reintroduce it to the planet! From New Scientist:

A tiny bacterium has been coaxed back to life after spending 120,000 years buried three kilometres deep in the Greenland ice sheet.

Researchers who found it say it could resemble microbes that may have evolved in ice on other planets.

Officially named Herminiimonas glaciei, the bug consists of rods just 0.9 micrometres long and 0.4 micrometres in diameter, about 10 to 50 times smaller than the well-known bacterium, Escherichia coli.

"What's unique is that it's so small, and seems to survive on so few nutrients," says Jennifer Loveland-Curtze of Pennsylvania State University, whose team has described the new species.

She speculates that thanks to its tiny dimensions, it can survive in minute veins in the ice, scavenging sparse nutrients that were buried along with the ice. It also has extensive tail-like flagella to help it manoeuvre through the veins to find food.

"Along with the snow, you get dust, bacterial cells, fungal spores, plant spores, minerals and other organic debris," says Loveland-Curtze. "So we postulate that it lives in these microniches in the ice."

Researchers in the team coaxed it back to life by keeping it at 2 °C for 7 months, then at 5 °C for a further four-and-a-half months, after which they saw colonies of very small purplish-brown bacteria.