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Thu November 28, 2013
By Accident, Scientists Discover Lakes Beneath Greenland
Originally published on Thu November 28, 2013 4:34 am
LINDA WERTHEIMER, HOST:
Flying to or from Europe, many a transatlantic traveler has gazed down at the brilliant white surface of Greenland and maybe wondered what is beneath those massive sheets of ice. Well, scientists have discovered jagged mountains, ravines that rival the Grand Canyon.
And now NPR's Richard Harris reports that for the first time they've come across some lakes under the ice as well.
RICHARD HARRIS, BYLINE: It's odd to think of pools of water sitting under thick sheets of ice, but in fact scientists have found more than 300 lakes under Antarctica. The question really for Greenland is why nobody has found lakes before now. Scientists, including Steven Palmer at the University of Exeter, are set up to look for them.
STEVEN PALMER: We've been flying an old 1943 DC3 aircraft fitted out with the latest scientific instruments.
HARRIS: Radar can measure the thickness of the ice, giving us clues about how rapidly it might melt. Radar can also find standing water. But despite a lot of looking, the first find happened quite by accident.
PALMER: We were flying from our base in Kanak, in the far northwest of Greenland, to a survey area in the northeast of Greenland, and we just happened to have the instruments turned on. We were checking out the instruments, making sure they were working OK.
HARRIS: And indeed they were. When they got a quick look at their test data, a couple of small features popped out.
PALMER: We pretty much instantly could see that they were lakes.
HARRIS: Small lakes, not much more than a mile long, buried under a half-mile of ice. The first question is where did that lake water come from. In an upcoming issue of Geophysical Research Letters, Palmer and colleagues suggest that there could be warm bedrock below, melting the ice. But more likely, he suspects that water starts on the surface and pours down through holes and cracks. In fact, surveys have found a lake on the surface above the hidden lakes.
PALMER: It doesn't form every year, this surface lake, this ice surface lake, but there is evidence that it has formed in the past. And there's evidence that it's drained in the past as well.
HARRIS: If that's the case, the under-ice lakes are probably flushed out frequently and refilled. That means biologists would find them boring, no long-lost ecosystems there.
But the lakes are still of considerable interest to glaciologists. And that's because as the lakes drain to the sea, Palmer says they flow under the Bodoin Glacier, lubricating the surface below.
PALMER: This requires further study. But it may be that these lakes are affecting the flow of the glacier downstream.
HARRIS: And that could influence how rapidly the glacier crumbles into the ocean as the planet warms.
So why are these the first lakes ever discovered in Greenland?
PALMER: This is a question we've struggled with, really, and in some ways it's hard to explain that.
HARRIS: It may simply be that Greenland is huge and the lakes are few and tiny. And sometimes it just pays to get lucky.
Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.