A staggering discovery on Mars came as a total surprise to scientists, and could have some absolutely huge implications as we seek to send a manned mission there in the coming decades. Researchers at NASA, studying the reams of data produced by the Curiosity rover, have determined that an ancient lake on Mars may have provided stable environmental conditions for multiple types of microbes.

Different parts of the lake had different conditions that would support different types of microbes, much like the conditions of lakes here on Earth, an exciting find that shows that the conditions for Martian life were there at one point. These lakes are long gone, with the lake that formerly existed in the Gale Crater likely disappearing three billion years ago.

The study was published in the journal Science under the titled, “Redox stratification of an ancient lake in Gale crater, Mars.” It is based on data gathered by Curiosity over the first three and a half years of its time on the Martian surface.

“We’re learning that in parts of the lake and at certain times, the water carried more oxygen,” said Roger Wiens, a planetary scientist at Los Alamos National Laboratory and co-author of the study, published today in the journal Science. “This matters because it affects what minerals are deposited in the sediments, and also because oxygen is important for life. But we have to remember that at the time of Gale Lake, life on our planet had not yet adapted to using oxygen–photosynthesis had not yet been invented. Instead, the oxidation state of certain elements like manganese or iron may have been more important for life, if it ever existed on Mars. These oxidation states would be controlled by the dissolved oxygen content of the water.”