Within ice that covers a salty, liquid Antarctic lake scientists have found and revived microbes that were at least 2,800 years old. The discovery, announced today, points to probable life within the underground lake and suggests the sort of ecosystem that might exist on Mars. The ancient microbes were in a state of suspended metabolism, similar to dormancy, said study team member John Priscu of Montana State University. “They’re in a frozen state,” Priscu said in a telephone interview. “They’ll come back to life if you add water.”