Molecular Ecological Analysis of Methanogens and Methanotrophs in Blanket Bog Peat I.R. McDonald, 1 M. Upton, 2, * G. Hall, 3 R.W. Pickup, 3 C. Edwards, 2 J.R. Saunders, 2 D.A. Ritchie, 2 J.C. Murrell 1 1 Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK 2 School of Biological Sciences, Life Science Building, University of Liverpool, Liverpool, L69 7ZB, UK 3 Institute of Freshwater Ecology, Far Sawrey, Ambleside, Cumbria, LA22 OLP, UK Received: 9 March 1999; Accepted: 21 June 1999 A B S T R A C T Methane production and methane oxidation potential were measured in a 30 cm peat core from the Moorhouse Nature Reserve, UK. The distribution of known groups of methanogens and methane oxidizing bacteria throughout this peat core was assessed. Using 16S rRNA gene retrieval and functional gene probing with genes encoding key proteins in methane oxidation and methanogen- esis, several major groups of microorganisms were detected. Methane production and oxidation was detected in all depths of the peat core. PCR amplification and oligonucleotide probing experiments using DNA isolated from all sections of the peat core detected methanotrophs from the groups Methylosinus and Methylococcus and methanogens from the groups Methanosarcinaceae, Metha- nococcaceae, and Methanobacteriaceae. 16S rDNA sequences amplified with the Methylosinus-specific primer were shown to have a high degree of identity with 16S rDNA sequences previously detected in acidic environments. However, no methanogen sequences were detected by the probes available in this study in the sections of the peat core (above 7 cm) where the majority of methanogenesis occurred, either because of low methanogen numbers or because of the presence of novel meth- anogen sequences. Introduction The atmospheric concentration of methane is estimated to be increasing at a rate of about 1% per annum [24]. As a greenhouse gas, methane is 20 times more active than car- bon dioxide and consequently, with current awareness of climate change, study of the major sources and sinks of atmospheric methane is clearly important. There are four major sources that contribute approximately equally to methane emissions in the natural environment: natural wet- lands and tundra, rice paddies, ruminants, and fossil fuels. In particular, wetlands contribute an estimated 15 to 20% of * Present Address: Oral and Dental Science, Microbiology Department, Bris- tol Dental School and Hospital, Bristol, BS1 2LY, UK Correspondence to: I.R. McDonald; Fax: 01203 523568; E-mail: I.R.McDonald@warwick.ac.uk MICROBIAL ECOLOGY Microb Ecol (1999) 38:225–233 DOI: 10.1007/s002489900174 © 1999 Springer-Verlag New York Inc.