Antarctic-like salty, water sucking soil could exist on Mars too
Washington: The frigid dry valleys in Antarctica may be a polar desert, yet their sandy soils actually suck moisture out of air, hinting at a similar possibility on Mars or on other planets.
Joseph Levy, post-doctoral researcher in Oregon State University College of Earth, Ocean, and Atmospheric Sciences, said it takes a combination of the right kinds of salts and sufficient humidity to make the process work.
But those ingredients are present on Mars and, in fact, in many desert areas on Earth, he pointed out, the journal Geophysical Research Letters reports.
"The soils in the area have a fair amount of salt from sea spray and from ancient fjords that flooded the region," said Levy, who earned his doctorate at Brown University, according to an Oregon State statement.
"Salts from snowflakes also settle into the valleys and can form areas of very salty soil. With the right kinds of salts, and enough humidity, those salty soils suck the water right out of the air," said Levy.
"If you have sodium chloride, or table salt, you may need a day with 75 percent humidity to make it work," he added.
"But if you have calcium chloride, even on a frigid day, you only need a humidity level above 35 percent to trigger the response."
Once brine forms by sucking water vapour out of the air, Levy said, the brine will keep collecting water vapour until it equalizes with the atmosphere. "It is like a siphon made from salt."
Levy and his colleagues, from Portland State University and Ohio State University, found that the wet soils created by this phenomenon were three to five times more water-rich than surrounding soils -- and they were also full of organic matter, including microbes, enhancing the potential for life on Mars.
Though Mars, in general, has lower humidity than most places on Earth, studies have shown that it is sufficient to reach the thresholds that Levy and his colleagues have documented.