As some of you may know, the Antarctic continent isn’t just ice all the way through. Although its surface is around 98 percent covered in frozen water, the remaining 2 percent gives a little hint as to what may lie below. Back in the Cretaceous period, when the non-avian dinosaurs still ruled the world, Antarctica was covered in dense, warm forests, built on a solid bedrock full of valleys, river, canyons, mountains, and lakes.
Three new studies focusing on the western subglacial Lake Whillans collectively reveal it to be a complex place; a wetland-like environment with both fresh and salty water, with rivers flowing from it across huge stretches of the southern continent. Beneath 800 meters (2,600 feet) of thick ice lies a truly unique world isolated from the surface by up to 1 million years – one whose actual liquid lake could be surprisingly young.
“This subglacial environment is analogous to a non-vegetated wetland within a terrestrial coastal plain,” the authors of one of the studies, published in Earth and Planetary Science Letters (EPSL), write. “The lacustrine (lake) history of the site is short, probably on the order of decades.”
Back in 2013, researchers were overjoyed when they removed an ice core from Lake Whillans and found that it contained 130,000 cells per milliliter of subglacial lake water – roughly the same density of life that is found in the darkest depths of the oceans. Despite not having seen sunlight for a century, life still existed at these frigid depths.
Until now, though, these researchers – many of which are part of the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project – didn’t have a good idea as to what the lay of the land down there was like. A trio of new papers have now alleviated some of the mystery, with the first, published in Geophysical Research Letters, describing its drainage system.
Global Positioning System (GPS) data gathered over five years from researchers at the University of California, San Diego, reveal that the lake drains periodically for several months, rather than continuously. When it does, the ice above becomes more slippery and can move around 4 percent faster than it normally would.
The EPSL study, led by researchers from Northern Illinois University, highlights that this flowing water moves around very slowly, so slowly in fact that it doesn’t have enough energy to move many sediments around. Not only does this mean that the bedrock there has barely changed over time, but the whole lake resembles a wetland within a coastal plain, like those along the coastline of the Gulf of Mexico.
Remarkably, they also suggest that the lake has only been this way for several decades. The last paper, published in the journal Geology and led by researchers at Montana State University, concludes from its own sedimentary analysis that this liquid water is mostly coming from the very recent melting of the base of the overlying ice, with a minor contribution from seawater trapped beneath it during a warmer, interglacial period.
All in all, Lake Whillans is a dynamic, paradoxically ancient and young environment like no other, and these new studies merely scratch the surface of this mysterious hidden realm. In any case, there’s plenty more out there to investigate, as this lake is actually just one of nearly 400 others concealed beneath the ice.