Listening practice: The lakes beneath Antarctic ice

Under Antarctica’s ice sheet, there is a hidden water system. Scientists have found hundreds of meltwater lakes beneath the ice, along with channels that can move water from one lake to another. These lakes are not open blue ponds. They are sealed under a continent-sized layer of ice, so no camera can simply look down at them. Yet the ice above them can reveal what is happening below. When a lake fills, the surface may rise. When it drains, the surface may sink. In a NASA explanation of Antarctic subglacial lakes, this movement is compared with a very slow signal written on the ice sheet itself. The water is hidden, but its effects reach the surface.