Nature Geosci. 1, 827–831 (2008)

Until recently, lakes beneath glaciers were regarded as static things. But Leigh Stearns of the University of Maine in Orono and her colleagues discovered that the gain and loss of water in such lakes contributes to the movement of the ice they underlie.

The team correlated a 10% increase in the flow speed of the Byrd Glacier in Antarctica between December 2005 and February 2007 (pictured) with satellite measurements showing a huge discharge of water from two subglacial lakes 200 kilometres upstream.

The lakes released about 1.7 cubic kilometres of water over roughly the same period, submerging spots at which the glacier was sticking and hence lubricating it.