Bacterial ecologies in limonite.
Limonite (Fe2O3 . nH2O) may be a constituent of the Martian surface. We have prepared culture media with ferric hydroxide as an electron acceptor. One medium contained ethanol, another gaseous hydrogen and carbon dioxide. Bacterial growth without light and oxygen suggests that ferric iron serves as a terminal respiratory electron acceptor. The oxidation of ferrous hydroxide may be carried out by photosynthetic bacteria. A ferrous-ferric couple may thus support bacterial respiration and photosynthesis in the absence of oxygen. This cycle may account for the dark markings of Mars.
Vishniac
W
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Department of Biology, University of Rochester, Rochester, New York, USA.
D000693:Anaerobiosis; D002245:Carbon Dioxide / Q000378:metabolism; D003470:Culture Media; D000431:Ethanol; D018559:Exobiology; D005290:Ferric Compounds / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D018535:Mars; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D012988:Soil Microbiology
D003470:Culture Media; D005290:Ferric Compounds; D002245:Carbon Dioxide; C021024:ferric hydroxide; D000431:Ethanol; D006859:Hydrogen; D007501:Iron