caa a22 4500 397552335 CHVBK 20180308164753.0 cr unu---uuuuu 161202e199602 xx s 000 0 eng 10.1111/j.1574-6941.1996.tb00203.x doi (NATIONALLICENCE)oxford-10.1111/j.1574-6941.1996.tb00203.x Regulation of methane oxidation in a freshwater wetland by water table changes and anoxia [Elektronische Daten] [Peter Roslev, Gary M. King] The effects of water table fluctuations and anoxia on methane emission and methane oxidation were studied in a freshwater marsh. Seasonal aerobic methane oxidation rates varied between 15% and 76% of the potential diffusive methane flux (diffusive flux in the absence of aerobic oxidation). On an annual basis, approximately 43% of the methane diffusing into the oxic zone was oxidized before reaching the atmosphere. The highest methane oxidation was observed when the water table was below the peat surface. This was confirmed in laboratory experiments where short-term decreases in water table levels increased methane oxidation but also net methane emission. Although methane emission was generally not observed during the winter, stems of soft rush (Juncus effusus) emitted methane when the marsh was ice covered. Indigenous methanotrophic bacteria from the wetland studied were relatively anoxia tolerant. Surface peat incubated under anoxic conditions maintained 30% of the initial methane oxidation capacity after 32 days of anoxia. Methanotrophs from anoxic peat initiated aerobic methane oxidation relatively quickly after oxygen addition (1-7 hours). These results were supported by culture experiments with the methanotroph Methylosinus trichosporium OB3b. This organism maintained a greater capacity for aerobic methane oxidation when starved under anoxic compared to oxic conditions. Anoxic incubation of M. trichosporium OB3b in the presence ofsulfide (2 mM) and a low redox potential (− 110 mV) did not decrease the capacity for methane oxidation relative to anoxic cultures incubated without sulfide. The results suggest that aerobic methane oxidation was a major regulator of seasonal methane emission from the investigated wetland. The observed water table fluctuations affected net methane oxidation presumably due to associated changes in oxygen gradients. However, changes from oxic to anoxic conditions in situ had relatively little effect on survival of the methanotrophic bacteria and thus on methane oxidation potential per se. © 1996 Federation of European Microbiological Societies. All rights reserved Methane oxidation nationallicence Methane emission nationallicence Water table changes nationallicence Methanotrophic bacteria nationallicence Anoxia tolerance nationallicence Roslev Peter Department of Biochemistry, Microbiology and Molecular Biology and Darling Marine Center, University of Maine, Walpole, ME 04573, USA aut King Gary M. Department of Biochemistry, Microbiology and Molecular Biology and Darling Marine Center, University of Maine, Walpole, ME 04573, USA aut FEMS Microbiology Ecology Blackwell Publishing Ltd 19/2(1996-02), 105-115 19:2<105 1996 19 femsec https://doi.org/10.1111/j.1574-6941.1996.tb00203.x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1111/j.1574-6941.1996.tb00203.x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Roslev Peter Department of Biochemistry, Microbiology and Molecular Biology and Darling Marine Center, University of Maine, Walpole, ME 04573, USA aut NATIONALLICENCE 700 1- King Gary M. Department of Biochemistry, Microbiology and Molecular Biology and Darling Marine Center, University of Maine, Walpole, ME 04573, USA aut NATIONALLICENCE 773 0- FEMS Microbiology Ecology Blackwell Publishing Ltd 19/2(1996-02), 105-115 19:2<105 1996 19 femsec Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford