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| Titel |
Miniaturized biosignature analysis reveals implications for the formation of cold seep carbonates at Hydrate Ridge (off Oregon, USA) |
| VerfasserIn |
T. Leefmann, J. Bauermeister, A. Kronz, V. Liebetrau, J. Reitner  , V. Thiel |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 5, no. 3 ; Nr. 5, no. 3 (2008-05-07), S.731-738 |
| Datensatznummer |
250002518
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| Publikation (Nr.) |
 copernicus.org/bg-5-731-2008.pdf |
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| Zusammenfassung |
| Methane-related carbonates from Hydrate Ridge typically show several
macroscopically distinguishable mineral phases, namely whitish aragonite,
lucent aragonite, and gray micrite. The relationship of these phases to
particular microorganisms or biogeochemical processes is as yet unclear. We
used a miniaturized biomarker technique on mg samples, combined with factor
analysis and subsequent electron microprobe analysis, to study lipid
biomarkers and chemical compositions of the individual phases. This allows
us to identify particular mechanisms involved in the formation of the
different carbonate precipitates. Our combined analysis of biomarkers and
petrographic traits shows that most of the lipids related to the anaerobic
oxidation of methane (>90% by weight) are concentrated within only a
minor compartment (~20% by volume) of the Hydrate Ridge carbonates,
the whitish aragonite. The patterns indicate that the whitish aragonite
represents fossilized biofilms of methanotrophic consortia containing mainly
archaea of the ANME-2 group and sulfate reducing bacteria, whereas the
precipitation of the lucent aragonite may have lacked the immediate
proximity of microorganisms during formation. By contrast, the gray micrite
formed by incorporation of allochthonous organic and inorganic matter during
carbonate precipitation induced by the anaerobic oxidation of methane
involving ANME-1 archaea. |
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