Recovery Lakes, East Antarctica: Radar assessment of sub-glacial water extent

In 2007 four new large subglacial lakes were reported in the upper reaches of the Recovery ice stream, in Dronning Maud Land, East Antarctica. The collective extent of these lakes, whose existence was deduced from satellite data, would have put them among Antarctica’s largest, second only to Lake Vostok.

Traverse

Photo: Stein Tronstad / Norwegian Polar Institute

Radar

The radar sled where Kirsty sat monitoring radar data as it was collected during the traverse. Photo: Kirsty Langley / Norwegian Polar Institute

However, analysis of new data collected on the ground during the 2008-2009 IPY Norwegian-U.S. Scientific Traverse of East Antarctica shows that the size of these lakes is greatly reduced from the initial estimate. The new evidence comes from ice penetrating radar and is the first ground-based data to be collected from this remote area of Antarctica since a pioneering traverse in the 1960s.

The radar data indicates that at least two of the lakes are in drained state. In addition, previously undetected water bodies were found in neighbouring areas. This new evidence confirms that there is a dynamic and widespread hydraulic system beneath the ice sheet, as has been predicted by models.

Water at the base of ice sheets significantly affects ice flow, and together with very soft sediments, aids streaming behaviour. The fast-flowing tributary of the Recovery ice stream penetrates more than 500 km inland, well into the interior of East Antarctica. This area has all the right ingredients to support fast transport of ice from the interior of Antarctica to the ocean. But the role of the large lakes and the impact of them draining and refilling on ice dynamics is still unclear.