Living it up below the ice sheet?

A recent earthquake at the bottom of the world suggests that Antarctic ice might hide an active, heat-generating fault, reports Robin E. Bell of Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y. The energy released at such a geologic boundary could power hot springs feeding into subsurface lakes, enabling microbial life to flourish miles beneath the top of the ice sheet, she speculates.

Radar shows Lake Vostok’s surface(arrow) under 4,000 meters of ice. Bell/SOAR

The epicenter of the mild Jan. 5 earthquake lines up with the centers of three older quakes near Lake Vostok. A body of water about the size of Lake Ontario, Lake Vostok’s been under 2 miles of ice for perhaps millions of years.

Data from the previous three quakes weren’t reliable enough to convince scientists that a well-defined fault existed, says Bell, who recently completed 3 years of radar observations through the ice.

The location of the new quake, however, greatly strengthens the case for a real geologic boundary, she says. The lake region is “not a piece of quiet old crust,” she says.

On another front, Bell’s radar results show that Lake Vostok has many coves and beaches at different depths, making it more complex than researchers previously thought. The newly found features complicate interactions between the lake and ice flowing over and around it, she says.

Scientists have found living microbes in the ice above Lake Vostok’s surface, but they haven’t yet sampled the lake itself, notes John C. Priscu of Montana State University in Bozeman (SN: 10/9/99, p. 230). Within the next decade, he hopes to test Vostok and other Antarctic lakes for signs of life. So far, however, concerns about contaminating the lake with aboveground microbes have prevented researchers from drilling into it.

Although researchers have no direct evidence of any lake life yet, Priscu speculates that Vostok could house complex creatures such as the tubeworms found near hydrothermal vents in the Atlantic and Pacific seafloors.