title: Solar-driven chemical energy source for a Martian biota.
abstract: Microorganisms deep in the Martian soil could derive energy indirectly from the sun via chemical reactions involving atmospheric products of the solar ultraviolet flux. The Viking discovery of a chemically uniform regolith which, though poor in organics, is rich in sulfur-containing compounds suggests reaction sequences in which sulfur is recycled through reduced and oxidized states by biologically catalyzed reactions with photochemically-produced atmospheric constituents. One candidate reaction, reduction of soil ssufate minerals by molecular hydrogen, is already exploited on earth by bacteria of the ubiquitous and tenacious Desulfovibrio genus.
mesh_terms: D003901:Desulfovibrio / Q000378:metabolism; D004734:Energy Metabolism; D005118:Extraterrestrial Environment; D008903:Minerals; D010084:Oxidation-Reduction; D010782:Photolysis; D012988:Soil Microbiology; D013026:Space Flight; D013431:Sulfates / Q000378:metabolism; D013472:Sunlight
chemical_list: D008903:Minerals; D013431:Sulfates