MICROBIOLOGICAL PROCESSES IN THE TERRESTRIAL CARBON-CYCLE - METHANE CYCLING IN PEAT

Coring and cutting devices were developed to extract 30 cm cores;from pear under conditions which preserve their physical/spatial integrity, maintain anoxic conditions and allow transverse sectioning. Methane p roduction potential, measured on 1-2 cm vertical sections, was broadly absent from the upper 5 cm, maximum in the next 10 cm and thereafter declined. Methane oxidation potential was maximum in the upper 10 cm a nd thereafter detected in reducing amounts. Molecular methods, based o n the extraction of total DNA and its PGR amplification and hybridisat ion with specific phylogenetic 16S rRNA and functional gene specific p rimers and probes, were developed to analyse the methane producing and methane oxidising microbial communities. The functional gene sequence s were based on methanogen methyl coenzyme reductase and methanotroph methane monooxygenase. Methanotrophs are located throughout the core w hereas methanogens are restricted to the lower zones. The composition of the microbial communities is however complex consisting of a number of novel species not previously recognised and with the various speci es/sub-groups occupying different vertical zones. (C) 1948 Elsevier Sc ience Ltd. All rights reserved.