Salty Antarctic Soils Suck Moisture from Atmosphere
29.02.2012 - Atmosphere & Space, Water & Oceans, Flora & Fauna, Antarctic
Salty soils in the McMurdo Dry Valleys region of Antarctica suck moisture out of the atmosphere, according to research led by Oregon State University geologist Joseph Levy.
In the study, published in Geophysical Research Letters, Levy and his colleagues explain that with the right kinds of salts and sufficient humidity, patches of moisture appear in the sandy soil in the McMurdo Dry Valleys – which are desert regions – despite a lack of snowmelt or precipitation in the region. As it sucks moisture form the atmosphere, brine forms in the salty areas of the soil and continues to siphon moisture from the atmosphere until an equilibrium is reached.
While humidity needs to be above 75% for the process to work for sodium chloride (NaCl), or table salt, with other salts, as is the case with calcium chloride (CaCl2), humidity only needs to reach 35% before the humidity siphoning process can take place.
Wet soils this phenomenon creates have moisture content 3-5 times greater than surrounding soils. More importantly, these areas are rich in organic matter, including microbes. If similar processes occur on the desert surface of Mars, it is an indication that primitive life might exist on the Red Planet in such areas where water is collected.
The heavy salt content of the soils in the McMurdo Dry Valleys comes from sea spray from the nearby Southern Ocean and from ancient fjords that flooded the region, according to Levy.