title: Substantial high-affinity methanotroph populations in Andisols effect high rates of atmospheric methane oxidation.
abstract: Methanotrophic bacteria in soils derived from volcanic ash (Andisols) were characterized via time series (13) C-phospholipid fatty acid (PLFA) labelling. Three Andisols were incubated under 2 ppmv (13) CH4 for up to 18 weeks, thus enabling high-affinity methanotrophs to be selectively characterized and quantified. PLFA profiles from all soils were broadly similar, but the magnitude of the high-affinity methanotrophic populations determined through (13) C-PLFA-stable isotope probing displayed sizeable differences. Substantial incorporation of (13) C indicated very large high-affinity methanotrophic populations in two of the soils. Such high values are far in excess (10×) of those observed for a range of mineral soils incubated under similar conditions (Bull et al., 2000; Maxfield et al., 2006; 2008a, b). Two of the three Andisols studied also displayed high but variable CH4 oxidation rates ranging from 0.03 to 1.58 nmol CH4 g(-1) d.wt. h(-1) . These findings suggest that Andisols, a previously unstudied soil class with respect to high-affinity methanotrophic bacteria, may oxidize significant amounts of atmospheric methane despite their low areal coverage globally.
authors.affiliation: Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK. Bristol Biogeochemistry Research Centre, Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, UK.
authors.forename: Pete J
authors.initials: PJ
authors.lastname: Maxfield
authors.forename: Ed R C
authors.initials: ER
authors.lastname: Hornibrook
authors.forename: Richard P
authors.initials: RP
authors.lastname: Evershed