PARIS - Salty water just below the surface of Mars could hold enough oxygen to support the kind of microbial life that emerged and flourished on Earth billions of years ago, researchers reported Monday (Oct 22).
In some locations, the amount of oxygen available could even keep alive a primitive, multicellular animal such as a sponge, they reported in the journal Nature Geosciences.
"We discovered that brines" - water with high concentrations of salt - "on Mars can contain enough oxygen for microbes to breathe," said lead author Vlada Stamenkovic, a theoretical physicist at the Jet Propulsion Laboratory in California.
"This fully revolutionises our understanding of the potential for life on Mars, today and in the past," he told AFP.
Up to now, it had been assumed that the trace amounts of oxygen on Mars were insufficient to sustain even microbial life.
"We never thought that oxygen could play a role for life on Mars due to its rarity in the atmosphere, about 0.14 per cent," Stamenkovic said.
By comparison, the life-giving gas makes up 21 per cent of the air we breathe.
On Earth, aerobic - that is, oxygen breathing - life forms evolved together with photosynthesis, which converts CO2 into O2. The gas played a critical role in the emergence of complex life, notable after the so-called Great Oxygenation Event some 2.35 billion years ago.
But our planet also harbours microbes - at the bottom of the ocean, in boiling hot springs - that subsist in environments deprived of oxygen.
"That's why - whenever we thought of life on Mars - we studied the potential for anaerobic life," Stamenkovic.
LIFE ON MARS?
The new study began with the discovery by Nasa's Curiosity Mars rover of manganese oxides, which are chemical compounds that can only be produced with a lot of oxygen.
Curiosity, along with Mars orbiters, also established the presence of brine deposits, with notable variations in the elements they contained.
A high salt content allows for water to remain liquid - a necessary condition for oxygen to be dissolved - at much lower temperatures, making brines a happy place for microbes.
Depending on the region, season and time of day, temperatures on the Red Planet can vary between minus 195 and 20 deg C.
The researchers devised a first model to describe how oxygen dissolves in salty water at temperatures below freezing.
A second model estimated climate changes on Mars over the last 20 million years, and over the next 10 million years.
Taken together, the calculations showed which regions on the Red Planet are most likely to produce brine-based oxygen, data that could help determine the placement of future probes.
"Oxygen concentrations (on Mars) are orders of magnitude" - several hundred times - "greater than needed by aerobic, or oxygen-breathing - microbes," the study concluded.Women's shoes Connie Size 10M Leather slip on pump NICE!!!Vintage Miu Miu Women Shoes size 38 made in ItalyStudio Works Black Strappy Slides Mules Open Toe Sandals Shoes Sz 7 Susan , DONALD J. PLINER SPORT 100% suede leather mules made in Italy women's 7 1/2 MLuichiny Women's Vay Kay Fashion Sneaker,Gold,5.5 M US , Women's Dansko Professional "Streamers" patent leather Clog Shoes 37 (US 7)MR. SEYMOUR WOMENS SHOES BRONZE BROWN LEATHER FLATS 7AAA CASUAL SHOE NIBRALPH LAUREN COLLECTION Purple Label Red Patent Leather Loafers Flats Sz 6.5 , VIVI G. WOMENS BLACK SUEDE TAUPE PATENT CAP TOE FLATS SHOES 40.5 / 9.5 NEWSkechers Street Women's Moda-Clean Street Fashion Sneaker, Leopard, Size 11.0 FH , STICO Chef Kitchen Slip Resistant Safety Men's Shoes Clog, US Size 5 -11 , Comfortview Black Hi Top Sneakers Size 7.5 Wide Women , Merrell Avian Ortholite Hiking Shoes Grey Purple Size US 6 Women's , Asics Womens Cross Freak 2 Lightweight Printed Running Shoes Sneakers BHFO 8149 , MERRELL womens size 6 brown suede slip on hiking walking camping shoes sneakers(B-7 ) Mizuno Wave Paradox 3 Womens SIZE 10 Running shoesWomens Hidden Wedge Heel High Tops Platform Sports Camo Canvas Sneakers Shoes G2Women's Womans Nike Shoes Size 7.5 Fashionable And Attractive Packages Athletic ShoesWomen's Modern Fiction Ballerina Crazy Price, Birmingham FlatsNike Air Presto Fly sz 7Y teal white 913966 301 ultra flyknit Womens 8.5 , ADIDAS SUPERSTAR 80s DECON, Ash Pink/Off White, CQ2587, Size 7Women's 9.5 Nike Flyknit Lunar 3 Running Shoes Sneakers Orange , New Balance Women's Sonic V1, Cyclone/Vintage, 9.5 B USBrooks Defyance 9 Running Shoes - Women's Size 8B, Grey/Teal/PurpleLa Sportiva Womens Akasha Blue Athletic Trail Running Shoes Size US 8 , Ahnu Montara II Sneakers eVent- Hiking Walking Waterproof Vibram Shoe Womens 6.5 , Saucony Grid Omni Walker Athletic Shoes - Women's Size 5, White , Anywear Women's Alexis Work Shoe, White/Black, Size 11.0Womens Size 7 DC Destroyer Hightops 320306Skecher's Avia Black synthetic Shoe 10
"Our results do not imply that there is life on Mars," Stamenkovic cautioned. "But they show that the Martian habitability is affected by the potential of dissolved oxygen."