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| Titel |
Temperature effects on the metabolic pathway of acetoclastic methanogenesis |
| VerfasserIn |
Yun-Ju Chen, Pei-Ling Wang, Chih-Hsien Sun, Li-Hung Lin |
| 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 |
250049527
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| Zusammenfassung |
| Methane is an important greenhouse gas. Of all methane producing mechanisms,
microbial methanogenesis accounts for a great proportion of methane budget. Thus,
determining the dominant methanogenic pathway would be critical to assess the microbial
potential for methane production and to delineate the interspecies regulation for
organic mineralization in anoxic, subsurface environments. Of various methanogenic
pathways, acetoclastic methanogenesis has been considered to account for 70% of
methane inventory in terrestrial environments. Methane production, however, switches
from acetoclastic pathway to acetate oxidizations coupled to hydrogenotrophic
methanogenesis with the increasing temperatures in some environments, such as rice fields
and petroleum reservoirs. In order to investigate the temperature effects on the
potential of acetoclastic methanogenesis associated with hydrocarbon seeps, sediments
collected from Kuan-Tzu-Ling in southwestern Taiwan were incubated with exogenous
acetate at different temperatures (from 30Ë C to 80Ë C) in anaerobic conditions.
Methane, carbon dioxide, and acetate concentrations, and carbon isotopic compositions
of methane were monitored through time. Molecular approaches targeting on the
detection of mcrA gene were also adopted to investigate the community assemblages of
methanogenic populations in incubated sediments. Our results showed that methane was
produced with the acetate consumption at different rates at different temperatures. The
fastest methane production occurred at 60~70Ë C. The δ13C values of methane
increased through time at low temperatures. At high temperatures, the δ13C values of
methane decreased through time. These lines of evidence suggest that the dominant
methanogenesis changed from acetatoclastic to hydrogentrophic pathways with the
increase of temperature. Further analyses of methanogenic populations are undergoing. |
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