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| Titel |
Analysis of biomolecules and microbial transformation products in gas field formation waters and in laboratory experiments simulating geological storage of carbon dioxide |
| VerfasserIn |
Andrea Kassahun, Thomas Muschalle, Claudia Gniese, Nils Hoth |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054996
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| Zusammenfassung |
| RECOBIO-2, part of the BMBF-Geotechnologien-funded research area on technologies for a
sustainable storage of carbon dioxide in geological formations, investigates the presence of
microbes in potential CO2 storage units and the effects of microbial activity on geological
CO2 storage unit properties. Formation water was sampled form two natural gas field sites
(Schneeren and Altmark; both operated by GDF SUEZ E&P Germany GmbH).
Rock material was obtained from exploration drilling cores of both gas fields (GDF
archives).
For both gas fields, molecular biological analysis revealed the presence of microorganisms,
among which autotrophic bacteria and archaea, able to transfer CO2 into organic carbon
(Ehinger et al., 2009; Gniese et al., 2010). Formation fluids contain dissolved organic carbon
in the range of 70 to 150 mg/l (occasional up to 1 g/l), dissolved inorganic carbon (several
tenths mg/l in Schneeren and several hundred mg/l in Altmark gas field) and dissolved
hydrogen (up to 3 μmol/l in Schneeren and up to 0.1 mmol/l in Altmark gas field). Up to
50 % of the total dissolved organic carbon was identified and qualified by single
compound analysis. It comprises carbonic acids (mostly formic and acetic acid),
alcohols (methanol, ethanol), methane, amino acids (free and in peptide bonds)
and sugars (polysaccharides). Furthermore, formation water ethylacetate extracts
contain elemental sulphur, linear and branched alkanes, dicarbonic acids and fatty
acids.
To reveal possible autotrophic microbial CO2 turnover processes, autoclave
experiments at elevated pressure and temperature conditions using microbial active
formation fluids, milled formation rock materials and mixed N2-CO2-H2-gas phases
were conducted (Muschalle et al., ). The experiments with Schneeren field site
materials showed a considerable CO2 consumption accompanied with a rise in
DOC-concentrations of the fluid phase from 70 mg/l to 2.7 g/l. Carbonic acids and
alcohols were present in the same proportion like in the formation waters prior to
incubation. Accordingly, the content of elemental sulphur, linear alkanes and fatty acids
in the ethylacetate extracts of the fluid phase increased. At some sampling dates,
sugar and amino acid concentrations of several tenths mg/l were detected. After the
experiments, the incubated rock material was analyzed for proteins and polysaccharides
using fluorescence microscopy. Protein covers of particle surfaces developed during
incubation and were visualized by DTFA staining. Associated to protein films,
polysaccharide and calcium accumulations were detected using calcofluor white and
calcein stains. Interestingly, no carbonates could be extracted from the incubated rock
material using sequential extraction techniques. This fact strengthens the hypothesis of
autotophic microbial CO2 turnover into organic material during geological CO2
storage.
Ehinger, S., Seifert, J., Kassahun, A., Schmalz, L., Hoth, N., Schlömann, M. (2009):
Predominance of methanolobus spp. and methanocolleus spp. in the archaeal communities of
saline gas field formation fluids, Geomicrobiology, 26, 326-338
Gniese, C., Hoth, N., Krüger, M., Frerichs, J., Kassahun, A., Seifert, J., Schlömann, M.
(2010): Analysis of active microorganisms in the natural gas reservoir Altmark (Germany)
and their potential role in CO2 turnover, BIOspektrum Sonderausgabe 2010 VAAM
Jahrestagung (Poster)
Muschalle, T., Gniese, C., Kassahun, A., Krüger, M., Hoth, N. (2011): Autoclave
experiments on autotrophic metabolism under elevated pressure and temperature by
microbes from a mature german natural gas field, Poster EGU 2011, this volume |
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