Buried under thousands of feet of ice in the Antarctic are a series of fresh water lakes unexposed to the open air for millions of years but possibly holding a thriving community of microbes, scientists say. Researchers probing beneath the permanent ice shield around the South Pole have located at least 76 lakes, including one that is about 5,400 square miles, comparable to Lake Ontario. Lake Vostok, the largest of the polar lakes, lies beneath more than two miles of ice and is thought to have a liquid pool with a depth of about 3,000 feet, said John C. Priscu of Montana State University. Probing Lake Vostok may help in the future search for life in outer space. Priscu said the lake may resemble subsurface lakes thought to exist on Mars and on Europa, a moon of Jupiter.