Being one of the most extreme environments on our planet, it was once assumed that the snowpacks deep within the polar regions were a sterile environment, totally devoid of life.

However, for the very first time, researchers have directly detected metabolically active microbial life altering the environment inside the snowpack, proving it's perfectly capable of supporting life. Their research was recently published in the Journal of the Royal Society Interface.

This is especially fascinating for scientists as it makes finding habitable planets in the universe all the more likely. Not only that, the study of the deeply compacted snow and ice is providing insights into prehistoric levels of carbon dioxide that could increase our understanding of climate change and the history of Earth's atmosphere.

"The fact that we have observed metabolically active bacteria in the most pristine ice and snow is a sign of life proliferating in environments where you wouldn't expect it to exist," lead author Dr Kelly Redeker, from the Department of Biology at the University of York, said in a statement. "This suggests we may be able to broaden our horizons when it comes to thinking about which planets are capable of sustaining life." 

"As microbial activity and its influence on its local environment has never been taken into account when looking at ice-core gas samples it could provide a moderate source of error in climate history interpretations," he added. "Respiration by bacteria may have slightly increased levels of CO₂ in pockets of air trapped within polar ice caps meaning that before human activity CO₂ levels may have been even lower than previously thought."

The researchers studied ice cores from snowpacks, layers of snow and ice that accumulate over centuries, deep within the Arctic and Antarctic. Within these samples, they discovered unusually high levels of methyl iodide – a gas produced by marine bacteria – using technology that can detect the presence of gases even at part-per-trillion levels.

Polar snowpacks are harsh environments for a few reasons. First of all, they are obviously pretty cold, capable of reaching -34ºC (-29.2 ºF). Paired with that they are battered with a huge amount of UV radiation and aren't particularly rich in nutrients. Perhaps then, the researchers pose, this could broaden our understanding of where life could live in extreme and seemingly inhospitable environments outside of our planet.

"We know that bacteria have the potential to remain viable and metabolically active at low temperatures for hundreds to thousands of years," said Redeker. "The next step is to look further down to see if we can observe active bacteria deep in the ice caps."