Fluxes of methane and carbon dioxide on peat-mining areas in Sweden

Drainage and peat harvesting may induce considerable changes in the fluxes to the atmosphere of the greenhouse gases CH4 and CO2 in peatlands. In this study, fluxes of CH4 and CO2 were measured with the closed chamber method in 6 Swedish peatlands that are being mined. Fluxes of CH4 were much higher from ditches than from mining "strips", i.e. emissions from ditches domina ted in most peatlands. The total CH4 emission during the growing season (0. 41 to 4.5 g CH4 m(-2) yr(-1)) was similar to emissions from virgin peatland s. Emissions from ditches can probably be kept low by keeping the ditches c lear from vegetation. Like CH4, CO2 was released to the atmosphere from bot h ditches and strips in most peatlands. The total emission during the growi ng season (0.23 to 1.0 kg CO2 m(-2) yr(-1)) was strongly dominated by the s trips. Compared to the total peat yield during mining these CO2 emission ra tes imply that on average ca 6% of the peat carbon is lost by microbial dec omposition in the mire.