NORFOLK, Va., Jan. 8 (UPI) -- Researchers say an up-close look at pictures taken by NASA's Mars rover Curiosity reveal geological patterns in the planet's rock that suggest microorganisms were once present.
The Martian sedimentary rock, say scientists at Old Dominion University, in Virginia, resembles geologic structures on Earth that were created by multilayered sheets of microbes called microbial mats.
"We can detect sedimentary structures in rocks on Mars using the rover images," Dr. Nora Noffke, a geoscientist at ODU, told The Huffington Post via email. "The structures I describe belong to a group of microbial structures that form by the interaction of benthic (living on the ground) microbes with sediment dynamics (erosion) in clastic deposits such as sand."
On Earth, researchers have long observed the effects of carpet-like microbial mats, which reorganize sediments on the sandy beds of shallow lakes and coastal regions. Scientists refer to the distinctive patterns left behind as microbially-induced sedimentary structures, or MISS.
Noffke says images taken by NASA's Curiosity rover of Gillespie Lake's Yellowknife Bay, an outcropping of the now dry lakebed, reveal a similar phenomenon.
And while she can't confirm life on Mars, she says there's plenty of evidence to support her hypothesis that microorganisms once lived in Martian soil.
"The fact that she pointed out these structures is a great contribution to the field," Penelope Boston, a geomicrobiologist at the New Mexico Institute of Mining and Technology, told Astrobiology Magazine. "Along with the recent reports of methane and organics on Mars, her findings add an intriguing piece to the puzzle of a possible history for life on our neighboring planet."
But while evidence that Mars once hosted life continues to mount, some scientists point out that such patterns can be made by non-living phenomena.
"I've seen many papers that say 'Look, here's a pile of dirt on Mars, and here's a pile of dirt on Earth,' said Chris McKay, a planetary scientist at NASA's Ames Research Center. "'And because they look the same, the same mechanism must have made each pile on the two planets.' That's an easy argument to make, and it's typically not very convincing."
"However, Noffke's paper is the most carefully done analysis of the sort that I've seen, which is why it's the first of its kind published in Astrobiology."
McKay is the editor of the Astrobiology, the journal in which Noffke's work was recently published.
