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TitreLow temperature S0 biomineralization at a supraglacial spring system in the Canadian High Arctic
AuteurGleeson, D F; Williamson, C; Grasby, S E; Pappalardo, R T; Spear, J R; Templeton, A S
SourceGeobiology vol. 9, no. 4, 2011 p. 360-375,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20110179
Documentpublication en série
Mediapapier; en ligne; numérique
Lat/Long OENS-81.6667 -81.5000 81.0333 81.0000
Sujetssoufre; eau sulfureuse; teneur en soufre; sources; géochimie de l'eau de source; hydrogéologie; géochimie; géologie de l'environnement
Illustrationslocation maps; photographs; tables; pie charts; photomicrographs
ProgrammeBassin sédimentaire Sverdrup, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Elemental sulfur (S0) is deposited each summer onto surface ice at Borup Fiord pass on Ellesmere Island, Canada, when high concentrations of aqueous H2S are discharged from a supraglacial spring system. 16S rRNA gene clone libraries generated fromsulfur deposits were dominated by b-Proteobacteria, particularly Ralstonia sp. Sulfur-cycling micro-organisms such as Thiomicrospira sp., and e-Proteobacteria such as Sulfuricurvales and Sulfurovumales spp. were also abundant. Concurrent cultivation experiments isolated psychrophilic, sulfide-oxidizing consortia, which produce S0 in opposing gradients of Na2S and oxygen. 16S rRNA gene analyses of sulfur precipitated in gradient tubes show stable sulfur-biomineralizing consortia dominated by Marinobacter sp. in association with Shewanella, Loktanella, Rubrobacter, Flavobacterium, and Sphingomonas spp. Organisms closely related to cultivars appear in environmental 16S rRNA clone libraries; none currently known to oxidize sulfide. Once consortia were simplified to Marinobacter and Flavobacteria spp. through dilution-to-extinction and agar removal, sulfur biomineralization continued. Shewanella, Loktanella, Sphingomonas, and Devosia spp. were also isolated on heterotrophic media, but none produced S0 alone when reintroduced to Na2S gradient tubes. Tubes inoculated with a Marinobacter and Shewanella spp. co-culture did show sulfur biomineralization, suggesting that Marinobacter may be the key sulfide oxidizer in laboratory experiments. Light, florescence and scanning electron microscopy of mineral aggregates produced in Marinobacter experiments revealed abundant cells,with filaments and sheaths variably mineralized with extracellular submicron sulfur grains; similar biomineralization was not observed in abiotic controls. Detailed characterization of mineral products associated with low temperature microbial sulfur-cycling may provide biosignatures relevant to future exploration of Europa and Mars.