Subglacial lakes may not be isolated ecosystems.

Large volumes of water occasionally flow between the lakes that lie deep beneath Antarctica's kilometers-thick ice sheet, a new analysis suggests.

In late 1996, radar altimeters on a European Space Agency satellite began to measure a drop in elevation across a 60O-square-kilometer area of eastern Antarctica. During the next 16 months, the surface elevation fell about 3 meters, indicating a loss of water from a lake that probably lies beneath the region, report Andrew Shepherd of the University of Edinburgh and Duncan J. Wingham of University College London. During that same period, the ice over two subglacial lakes 290 km away rose about 50 centimeters and 2 m, respectively.

Researchers have found more than 145 subglacial lakes in Antarctica, some of which may contain microbes (SN: 10/9/99, p. 230) and higher forms of life (SN: 3/3/01, p. 139). Most scientists had presumed that those ecosystems have been isolated since the continent's ice sheet formed millions of years ago. However, the new findings hint that many of the lakes may be linked by subglacial tunnels that transfer water and organisms between the covered bodies of water.--S.P.