An ancient Martian lake had conditions suitable for different types of microbes to survive, according to a new research that looked at findings from NASA’s Curiosity rover mission’s first 42 months. The lake provided stable environmental conditions that differed significantly from one part of the lake to another, the study said. While previous work had revealed the presence of a lake more than three billion years ago in Mars’ Gale Crater, this study published in the journal Science defines the lake’s chemical conditions and uses Curiosity’s powerful payload to determine that the lake was stratified. Stratified bodies of water exhibit sharp chemical or physical differences between deep water and shallow water.
In Gale’s lake, the shallow water was richer in oxidants than deeper water was. “These were very different, co-existing environments in the same lake,” lead author of the report Joel Hurowitz of Stony Brook University in New York said. “This type of oxidant stratification is a common feature of lakes on Earth, and now we’ve found it on Mars. The diversity of environments in this Martian lake would have provided multiple opportunities for different types of microbes to survive,” Hurowitz said. Whether Mars has ever hosted any life is still unknown, but seeking signs of life on any planet, whether the Earth, Mars or more-distant icy worlds, begins with reconstruction of the environment to determine if it was capable of supporting life.
NASA is using Curiosity to explore habitable environments on the ancient surface of Mars. “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 in New Mexico and co-author of the study. “This matters because it affects what minerals are deposited in the sediments, and also because oxygen is important for life,” Wiens said.