Effects of land-use on the activity and diversity of methane oxidizing bacteria in forest soils

Methane is an important greenhouse gas and CH4 oxidation in soil represents a significant sink for this gas. High capacity CH4 oxidation potentials and molecular profiles Of CH4 oxidizing bacteria in soil were compared for five land-use treatments at a fully replicated experimental site within the Gisburn Forest Experiment, to assess the effects of land-use on both the potential activity of CH4 oxidizing bacteria and their diversity. Forestry land-use was found to have a highly significant effect on CH4 oxidation potentials. Highest CH4 oxidation potentials were found in soils collected under stands of oak, in grassland plots, and in one soil under Norway spruce. A negative relationship between soil water nitrate concentration and CH4 Oxidation capacity was evident across the experimental site, with the high nitrate soils under stands of alder exhibiting little or no capacity for CH4 oxidation even at optimal temperature and water content. Molecular profiles indicated that a diverse range of bacteria with the potential to oxidize CH4 were present in all soils, however no clear correlation with CH4 oxidation potential was identified. (C) 2001 Elsevier Science Ltd. All rights reserved.