THE EFFECT OF DISTURBANCE ON THE STABILITY AND FUNCTION OF METHANOTROPHS UNDER DIFFERENT ENERGY FLOWS

S. Krause, P. Frenzel

Onderzoeksoutput: Bijdrage aan conferentiePaperWetenschappelijk

Samenvatting

Methane is next to water vapor and carbon dioxide the third most important greenhouse gas. The largest single sources are natural wetlands and wetland rice fields. In wetland rice fields, aerobic methanotrophs play a key role oxidizing methane before it is released to the atmosphere. However, it has been shown that methanotrophs are affected by nitrogen fertilization, a common agricultural practice in rice fields. We tested two hypotheses: (1), nitrogen fertilization has an inhibitory effect, and (2), methanotrophs are more resilient at high energy flows. We used microcosms supplementing a thin layer of water-saturated paddy soil from below with methane and from above with air. We used two different source strengths of methane resulting in a different flux into the oxic-anoxic boundary, and, hence, different energy flows through the community. Ammonium-based fertilization was applied at high and low energy flows. We analyzed the different communities with a pmoA specific microarrays (pmoA: gene encoding a subunit of the methane monooxygenase), and used ordination and indicator species to unravel the effects of energy flow and fertilization. Different energy flows had a significant influence on the methanotrophic community, while fertilization had not. Fertilization did not affect methane oxidation activity. Indicator species analysis revealed the genus Methylobacter and an environmental cluster strictly affiliated with paddy soils as indicative for high energy flows. Based on these results we rejected the first (effect of fertilization), but could support the second hypothesis (energy flow). We suggest that methanotrophs are adapted to particular environments, and that changes in the energy flow have major effects for the community structure.
Originele taal-2Engels
StatusGepubliceerd - 2010

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