RESUMO
Methane oxidation in the cover soil of the Khmet'evo municipal landfill in Moscow oblast was investigated. Methane emission from the experimental parcel of the site was highly inhomogeneous. At a depth of 45-60 cm, the pore gas mainly consisted of CH4 (60-70%) and CO2 (30-40%). In the upper horizons of the cover soil, the concentration of these gases sharply decreased. Techniques for estimation of the methane-oxidizing activity in the cover soil of the landfill were tested. The rate of methane oxidation in the soil, the factor limiting methane emission from the surface of the site, correlated with the cell number of culturable methanotrophic bacteria. The method of indirect immunofluorescence revealed ten known species of methanotrophic bacteria in enrichment cultures obtained from samples of the cover soil. Our results also indicate the presence of unknown psychrotolerant methanotrophs that are active at the low temperatures characteristic of Moscow oblast.
