An ancient lake with drinkable water once thrived, and in it theoretically could have floated (or swam) mineral-eating life forms. NASA's Mars rover, Curiosity found traces of the ancient fresh water lake. This scenario of life not being contained is possible and even probable because mineral-eating creatures thrive in exotic waters here on Earth today. These life forms that eat minerals instead of plants or other sea creatures are called chemolithoautotrophs. It's a fancy name for mineral eaters. This opens the possibility of life on other planets evolving without having to have plants to eat by consuming minerals in rocks and dirt or dissolved in water.
The discovery of an ancient fresh water lake on Mars is detailed in the December 9, 2013 Washington Post article by Joel Achenbach, "NASA Curiosity rover discovers evidence of freshwater Mars lake." or view the photo gallery: Curiosity on Mars: The rover nears a ridge named “Cooperstown,” a possible site for contact inspection with tools on the robotic arm. Or you can view the NASA video. The article, "Ancient proof of Mars lake," also is reprinted today in the Sacramento Bee newspaper.
In NASA's animated video, you can see the area on Mars where the Curiosity rover recently discovered evidence of an ancient lake. Narration is by John Grotzinger, a Caltech planetary geologist who is the chief scientist of the Curiosity rover mission.
How the ancient freshwater lake came into view happened because of NASA's reconnaissance of Mars with the Curiosity rover. The ancient lake on Mars had fresh water that scientists think had been drinkable. That environment usually leads to life forms that drink the water, and if no plants existed at the same time as the ancient lake, then the life forms existed by eating minerals.
It's possible to have life forms eat only minerals and drink water. The freshwater lakes existed for perhaps millions of years. That would give the mineral eaters time to evolve into possibly higher life forms. Now the question is whether everything alive on Mars at that time ate minerals or whether the freshwater lakes eventually led to plant life on the planet near the freshwater lakes?
The temperature on Mars would have been cold. And the freshwater lakes probably froze over. But what scientists did find was that Mars had freshwater at one time. But is there any frozen freshwater today harboring the mineral-eaters? See, "Curiosity rover mission finds proof of water on Mars: The Mars Curiosity rover has sent back photographs that show evidence of a “vigorous” streambed."
You also can check out the animated video from NASA that shows the area on Mars where the Curiosity rover recently discovered evidence of an ancient lake. Narration in the video is by John Grotzinger, a Caltech planetary geologist who is the chief scientist of the Curiosity rover mission.
On December 9, 2013 the new findings appear online in the journal Science and were discussed in San Francisco at the fall meeting of the American Geophysical Union. If you find a map of Mars, look for the fresh water lake in the Gale Crater. Scientists also looked at the age of the rocks. What scientists look for are organic molecules that show how ancient microbes thrived.
Gale Crater is in an area with rocks about 4.2 billion years old
The mineral eaters, if they existed would have lived in the freshwater lake around just a little more than 3.5 billion years ago. It was a large freshwater lake, close to the size and shape of one of New York’s Finger Lakes, according to the Washington Post article, "NASA Curiosity rover discovers evidence of freshwater Mars lake." What scientists did explain, however, was that the lake thrived in a habitable environment that lasted a long time in geological years. Mars had groundwater and rivers for eons.
If you look at the older studies on Mars, some of them claim the groundwater was very acidic, but new evidence that looks at the freshwater lake says it was drinkable, similar to Earth water. The freshwater lake on Mars had water so 'drinkable' that if you dropped a bunch of Earth microbes into it, they would multiply and thrive, probably in good health. You can read more information in John Grotzinger's paper, “A Habitable Fluvio-Lacustrine Environment at Yellowknife Bay, Gale Crater, Mars.” Grotzinger is a Caltech planetary geologist and chief scientist of the Curiosity rover mission. Also, you may wish to check out the abstract of a presentation, "Abstract: An Overview of Curiosity's Search for Ancient Habitable Environments."
The fact is Mars once had an environment much like the Earth. To check this theory, you have only to look at the chemistry of the old freshwater lake on Mars. On Earth mineral eaters live in caves or in the deep oceans staying inside hydrothermal vents.
The duration of this environment matters when it comes to habitability, said Jennifer Eigenbrode, a geochemist at NASA Goddard Space Flight Center and a co-author of three of the new papers. But scientists at the present still don't have the tools to find out whether mineral eaters actually lived on Mars at one time in those freshwater lakes.
The theory says it's possible because the water looks drinkable to Earthlings. But nobody really knows for sure yet. In the future as Earth beings colonize Mars, perhaps it can be transformed the way it was with more freshwater lakes and rivers. Only time will tell. For further information see the December 9, 2013 news articles, "NASA Rover Finds Signs of Freshwater Lake on Mars - WSJ.com" or "NASA Mars rover finds evidence of life-friendly ancient lake | Reuters."