Abstract

Wetlands are one of the major sources of atmospheric methane. However, not all methane produced by methanogens reaches the atmosphere as a substantial amount of CH₄ (1 to 90%) is recycled in soil aerobic zone by methanotrophic bacteria. It was found that methane oxidation is also conducted by methanotrophic bacteria endosymbionts ofSphagnum mosses. The aims of the study were to examine Sphagnum-involved CH₄oxidation in transition moor in Eastern Poland and the molecular studies of methanotrophic communities inhabiting Sphagnum recurvum. The identification of endosymbiotic methanotrophs was performed by polymerase chain reaction (PCR) andfluorescence in situ hybridization (FISH) techniques. The methanotrophic activity of submerged and non-submerged Sphagnum mosses was determined at the level of 7.6±0.1 and 2.5±0.1 mM CH₄g^-1DWday^-1 for complete plants from pool and lawn mosses, respectively. The highest activity was found in the top plants parts. On the basis of genomic analyses, it was found that endosymbionts belonged to methanotrophs of type I and II. The spread of Sphagnum species in peat bogs and the contribution of methanotrophic endosymbionts to methane recycling, (very important in relation to expected climate warming), could be greatly important in predicting the methane fluxes from wetlands.

Key words: Methane oxidation, methanotrophs, Sphagnum moss, symbiosis.