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| Titel |
Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan) |
| VerfasserIn |
J. Felden, A. Lichtschlag, F. Wenzhöfer, D. Beer, T. Feseker, P. Pop Ristova, G. Lange, A. Boetius  |
| 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 ; 10, no. 5 ; Nr. 10, no. 5 (2013-05-14), S.3269-3283 |
| Datensatznummer |
250018250
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| Publikation (Nr.) |
 copernicus.org/bg-10-3269-2013.pdf |
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| Zusammenfassung |
| The Amon mud volcano (MV), located at 1250 m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane
hydrocarbons into the hydrosphere. Previous investigations showed a low
efficiency of hydrocarbon-degrading anaerobic microbial communities
inhabiting the Amon MV center in the presence of sulfate and hydrocarbons
in the seeping subsurface fluids. By comparing spatial and temporal patterns
of in situ biogeochemical fluxes, temperature gradients, pore water composition, and
microbial activities over 3 yr, we investigated why the activity of
anaerobic hydrocarbon degraders can be low despite high energy supplies. We
found that the central dome of the Amon MV, as well as a lateral mud flow at
its base, showed signs of recent exposure of hot subsurface muds lacking
active hydrocarbon degrading communities. In these highly disturbed areas,
anaerobic degradation of methane was less than 2% of the methane flux.
Rather high oxygen consumption rates compared to low sulfide production
suggest a faster development of more rapidly growing aerobic hydrocarbon
degraders in highly disturbed areas. In contrast, the more stabilized muds
surrounding the central gas and fluid conduits hosted active anaerobic
hydrocarbon-degrading microbial communities. The low microbial activity in
the hydrocarbon-vented areas of Amon MV is thus a consequence of
kinetic limitations by heat and mud expulsion, whereas most of the outer MV area is limited by hydrocarbon transport. |
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