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| Titel |
Wetland restoration and methanogenesis: the activity of microbial populations and competition for substrates at different temperatures |
| VerfasserIn |
V. Jerman, M. Metje, I. Mandić-Mulec, P. Frenzel |
| 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 ; 6, no. 6 ; Nr. 6, no. 6 (2009-06-29), S.1127-1138 |
| Datensatznummer |
250003844
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| Publikation (Nr.) |
 copernicus.org/bg-6-1127-2009.pdf |
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| Zusammenfassung |
| Ljubljana marsh in Slovenia is a 16 000 ha area of partly drained fen,
intended to be flooded to restore its ecological functions. The resultant
water-logging may create anoxic conditions, eventually stimulating
production and emission of methane, the most important greenhouse gas next
to carbon dioxide. We examined the upper layer (~30 cm) of Ljubljana
marsh soil for microbial processes that would predominate in water-saturated
conditions, focusing on the potential for iron reduction, carbon
mineralization (CO2 and CH4 production), and methane emission.
Methane emission from water-saturated microcosms was near minimum detectable
levels even after extended periods of flooding (>5 months). Methane
production in anoxic soil slurries started only after a lag period of 84 d
at 15°C and a minimum of 7 d at 37°C, the optimum temperature for
methanogenesis. This lag was inversely related to iron reduction, which
suggested that iron reduction out-competed methanogenesis for electron
donors, such as H2 and acetate. Methane production was observed only in
samples incubated at 14–38°C. At the beginning of methanogenesis,
acetoclastic methanogenesis dominated. In accordance with the preferred
substrate, most (91%) mcrA (encoding the methyl coenzyme-M reductase, a key
gene in methanogenesis) clone sequences could be affiliated to the
acetoclastic genus Methanosarcina. No methanogens were detected in the original soil.
However, a diverse community of iron-reducing Geobacteraceae was found. Our results suggest
that methane emission can remain transient and low if water-table
fluctuations allow re-oxidation of ferrous iron, sustaining iron reduction
as the most important process in terminal carbon mineralization. |
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