METHANE AND CARBON-DIOXIDE CONCENTRATIONS IN BOGS AND FENS - WITH SPECIAL REFERENCE TO THE EFFECTS OF THE BOTANICAL COMPOSITION OF THE PEAT

1 The relation between concentrations of CH4 and CO2 and the botanical and chemical composition of peat is investigated. Peat was sampled fr om different mires in northern Sweden. The samples were from different depths and had different botanical compositions and degrees of humifi cation. 2 The concentration of CO2 in the peat water ranged between 0. 97 and 6.5 mm, and the concentration of CH4 varied between 0.05 and 1. 2 mm. 3 Methane concentrations were strongly correlated with depth (r2 = 0.63), but when the botanical composition and degree of humificatio n were also used in the model, the explained variance (r2) in CH4 conc entration was 72% and in CO2 concentration 56%. Concentrations of both gases were positively correlated with Sphagnum remains and negatively correlated with Carex remains in the peat. 4 When chemical and physic al variables were also used to model the gas concentrations of a subse t of samples, 65% of the variance in CO2 concentration was explained a nd positively correlated with Sphagnum remains and negatively with Car ex remains. In total, 75% of the variance of CH4 concentrations was ex plained. Most of the variance (65%) was positively correlated with dep th, Ni, S, Ca, K and Na.