title: Reaction sequence of iron sulfide minerals in bacteria and their use as biomarkers.
abstract: Some bacteria form intracellular nanometer-scale crystals of greigite (Fe3S4) that cause the bacteria to be oriented in magnetic fields. Transmission electron microscope observations showed that ferrimagnetic greigite in these bacteria forms from nonmagnetic mackinawite (tetragonal FeS) and possibly from cubic FeS. These precursors apparently transform into greigite by rearrangement of iron atoms over a period of days to weeks. Neither pyrrhotite nor pyrite was found. These results have implications for the interpretation of the presence of pyrrhotite and greigite in the martian meteorite ALH84001.
authors.affiliation: Department of Geology, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: M
authors.initials: M
authors.lastname: Pósfai
authors.forename: P R
authors.initials: PR
authors.lastname: Buseck
authors.forename: D A
authors.initials: DA
authors.lastname: Bazylinski
authors.forename: R B
authors.initials: RB
authors.lastname: Frankel
mesh_terms: D001419:Bacteria / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D015415:Biomarkers / Q000032:analysis; D003460:Crystallization; D005296:Ferrous Compounds / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D008280:Magnetics; D018535:Mars; D019110:Meteoroids; D013440:Sulfides / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D015415:Biomarkers; D005296:Ferrous Compounds; D013440:Sulfides; C111959:greigite; D007501:Iron; C022597:ferrous sulfide