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an unusual inverted saline microbial mat community in an interdune sabkha in the rub' alkhali (the empty quarter), uae: an analog for habitats on present marsSalt flats (sabkha) are a recognized habitat for microbial life in desert environments and as analogs for habitats for life on Mars. Here we report on the physical setting and microbiology of interdune sabkhas among the large dunes in the Rub' al Khali (the Empty Quarter) in Liwa Oasis, United Arab Emirates. The salt flats, composed of gypsum and halite, between the dunes are moistened by relatively fresh ground water from below. The result is a salinity gradient that is inverted compared to most salt flat communities with the hypersaline layer at the top and freshwater layers below. We describe and characterize a rich photosynthetically-based microbial ecosystem that is protected from the arid outside environment below the translucent salt crust. Gases collected from sediments under shallow ponds in the sabkha contain methane in concentrations as high as 3400 ppm. The salt layer provides environmental protection to the habitat below and could preserve biomarkers and other evidence for life in the salt after it dries out. Chloride-filled depressions have been identified on Mars and although the surface flow of water is unlikely on Mars today, ground water is possible. Such a near surface system with modern groundwater flowing under ancient salt deposits could be present on Mars and could be accessed by surface rovers.
Document ID
20160012254
Document Type
Preprint (Draft being sent to journal)
Authors
McKay, Christopher P.
(NASA Ames Research Center Moffett Field, CA United States)
Rask, Jon C.
(Wyle Labs., Inc. Moffett Field, CA, United States)
Detweiler, Angela M.
(Bay Area Environmental Research Inst. Petaluma, CA, United States)
Bebout, Brad M.
(NASA Ames Research Center Moffett Field, CA United States)
Everroad, R. Craig
(Bay Area Environmental Research Inst. Petaluma, CA, United States)
Chanton, Jeffrey P.
(Florida State Univ. Tallahassee, FL, United States)
Mayer, Marisa H.
(NASA Ames Research Center Moffett Field, CA United States)
Caraballo, Adrian A. L.
(NASA Ames Research Center Moffett Field, CA United States)
Kapili, Bennett
(NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
October 11, 2016
Publication Date
January 12, 2016
Subject Category
Lunar and Planetary Science and Exploration
Report/Patent Number
ARC-E-DAA-TN29373
Funding Number(s)
CONTRACT_GRANT: NNA14AB82C
CONTRACT_GRANT: NNX13AO05A
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Hypersaline environments in deserts
microbial life in salt flats (sabkha)

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