Massive Flood Impacts Antarctic Subglacial Lake

Deep beneath the Antarctic ice cap lie buried lakes, storing hundreds of thousands of gallons of fresh water. Thus far, nearly 380 of these ice-locked pockets have been discovered. Now, though, scientists are slowly realizing the dangers of these lakes--they possess the potential of unleashing massive floods as the ice melts.

Between 2007 and 2008, one of these lakes burst its banks. It ended up releasing a massive six billion tons of water directly into the ocean, according to Discovery News. The largest flooding event ever recorded on the continent, it revealed how quickly environmental shifts can change as water builds up over time.

Actually detecting this flood wasn't as easy as you might expect, though. Since the lake was beneath the ice, it "flooded" in a way that didn't make it visible to the naked eye. Instead, researchers used satellites to map the crater that developed as the almost 2-mile-thick overlying ice sheet slumped to fill the void left by the escaping water, according to BBC News. The crater itself is huge, covering an area of about 260 square kilometers. While scientists knew that there had been a large elevation change in the crater, they didn't realize exactly how big it was until the recent study.

After calculating the amount of water that must have been inside this massive pocket, the researchers found that the peak discharge of the liquid must have been more than double the normal flow rate of London's River Thames. The findings mean that it's possible for massive amounts of fresh water to be dumped into the ocean which could, in turn, change the composition of the seas.

 "There's a lot of mystery surrounding the continent still that we don't understand," said Hugh Corr, the study co-author, in an interview with LiveScience.com. "This will be modeled in terms of the ice dynamics and the thermal impacts of this feature, and that will add to the general knowledge of the continent."

As the climate changes, rising sea levels are a major concern. These lakes hold the potential to "dump" a massive amount of freshwater into the oceans in a relatively short amount of time.

"This one lake on its own represents 5-10 percent of [Antarctica's] annual mass imbalance," said Andy Shepherd, one of the co-authors of the new study, in an interview with BBC News. "If there are nearly 400 of these sub-glacial lakes then there's a chance a handful of them are draining each year, and that needs to be considered."

The findings are published in the journal Geophysical Research Letters.