The findings, detailed in the Proceedings of the National Academy of Sciences, describe the microbes’ Lake Vida habitat as aphotic (with little or no light), anoxic (without oxygen), and slightly acidic brine with a temperature of -13C. Carbon dating has indicated that the inhospitable-sounding brine has been isolated for more than 2,800 years.

“This provides us with new boundary conditions on the limits for life,” said Peter T Doran, a professor at the University of Illinois’ Earth and Environmental Science department, in a press release. “The low temperature or high salinity on their own are limiting, but combined with an absence of solar energy or any new inputs from the atmosphere, they make this a very tough place to make a living.”

Previous studies of the brine in Lake Vida from 2002 had discovered the presence of ancient microbes, however these needed to be thawed before life signs were observed. The most recent result showed Vida to contain a diverse and metabolically active bacteria-dominated ecosystem.