Researchers are getting the first look into into the biogeochemistry, geophysics and geology of subglacial Lake Whillans, which lies 800 meters (2,600 feet) beneath the West Antarctic Ice Sheet.
Three recent publications at three different institutions across the United States talk of the exciting possibilities of the discovery and some are asking if this could mean there could be an eighth continent under the Ocean.
The findings stem from the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project funded by the National Science Foundation (NSF).
Collectively, the researchers describe a wetland-like area beneath the ice. Subglacial Lake Whillans is primarily fed by ice melt, but also contains small amounts of seawater from ancient marine sediments on the lake bed. The lake waters periodically drain through channels to the ocean, but with insufficient energy to carry much sediment.
In recent decades, researchers, primarily using airborne radar and satellite laser observations, have discovered that a continental system of rivers and lakes — some similar in size to North America’s Great Lakes — exists beneath the miles-thick Antarctic Ice Sheet. These findings represent some of the very first methodical descriptions of one of those lakes based on actual sampling of water and sediments.
In January 2013, the WISSARD project successfully drilled through the ice sheet to reach subglacial Lake Whillans, retrieving water and sediment samples from a body of water that had been isolated from direct contact with the atmosphere for many thousands of years. The team used a customized, clean hot-water drill to collect their samples without contaminating the pristine environment.
WISSARD was preceded by ongoing field research that began as early as 2007 to place this individual lake in context with the larger subglacial water system. Those investigations and the sampling of Subglacial Lake Whillans were funded, and the complex logistics provided by, the NSF-managed U.S. Antarctic Program.
Some of the initial analyses of the samples taken from the lake are highlighted in the recent papers, published in three different journals by three scientists whose graduate work was funded, at least in part, through the WISSARD project. They used an array of biogeochemical, geophysical and geological methods to provide unique insights into the dynamics of the subglacial system.
The findings indicate that lake water comes primarily from melting at the base of the ice sheet covering the lake, with a minor contribution from seawater, which was trapped in sediments beneath the ice sheet during the last interglacial period, when the Antarctic Ice Sheet had retreated. This ancient, isolated reservoir of ocean water continues to affect the biogeochemistry of this lake system. This new finding contrasts with previous studies from neighboring ice streams, where water extracted from subglacial sediments did not appear to have a discernable marine signature.
Together, these new publications highlight an environment where geology, hydrology, biology and glaciology all interact to create a dynamic subglacial system, which can have global impacts.
Helen Amanda Fricker, a WISSARD principal investigator and a professor of geophysics at Scripps, who initially discovered subglacial Lake Whillans in 2007 from satellite data, said: “It is amazing to think that we did not know that this lake even existed until a decade ago. It is exciting to see such a rich dataset from the lake, and these new data are helping us understand how lakes function as part of the ice sheet system.”
Understanding and quantifying this and similar systems, she added, requires training a new generation of scientists who can cross disciplinary boundaries, as exemplified by the WISSARD project. Picture of an artist’s conception of the Antarctic subglacial environment: Zina Deretsky. – National Science Foundation.