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| Titel |
Methanotrophy in surface sediments of streams |
| VerfasserIn |
Alexandre Bagnoud, Paraskevi Pramateftaki, Hannes Peter, Tom Battin |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250149711
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| Publikation (Nr.) |
 EGU/EGU2017-14088.pdf |
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| Zusammenfassung |
| Because streams are often found to be supersaturated in methane (CH4), they are considered
as atmospheric sources of this greenhouse gas. However, little is known about the processes
driving CH4 cycling in these environments, i.e. production, consumption and fluxes. CH4 is
thought to be produced in deeper anoxic sediments, before it migrates up to reach the oxic
stream water, where it can be oxidized by methanotrophs. In order to gain insights into this
process, we investigated 14 different streams across Switzerland. We characterized
the chemistry of surface and sediment waters by measuring dissolved chemical
profiles. We also sampled surface sediments and determined methanotrophic rates
with laboratory incubations and Michaelis-Menten modeling. Interestingly, rates
were strongly correlated with the CH4 concentrations in stream waters, rather
than in sediment waters. This indicates that methantrophic populations feed on
CH4 from the surface streamwater, even though CH4 concentrations are higher in
the sediment waters. Methanotrophy rates were also correlated with Crenothrix
counts (based on 16S rRNA sequencing), a strict methanotroph, while this latter
was correlated with pmoA counts (based on quantitative PCR), a gene involved
in methanotrophy. These results show that Crenothrix genera are the most active
methanotrophs in surface sediments of streams, and can represent more than 2% of microbial
communities. Remarkably, the dominating Crenothrix species was detected in all 14
samples. This work allows the assessment of in situ methanotrophic rates, of the
environmental parameters driving this process, and of the microbial populations
carrying it out, and thus brings useful insights about carbon cycling in streams. |
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