Methane and carbon dioxide evolution from subarctic fens.

Abstract

Rates of net methane and carbon dioxide evolution from four subarctic fens over one summer ranged from 0 to 7 mmol CH4 m-2d-1 and from 2 to 29 mmol CO2 m-2d-1. Average molar ratios of carbon dioxide to methane ranged from 3 to 10. Partially because of the high spatial variability in evolution rates, the temperature dependence of carbon dioxide was weak, but stronger for methane, with significant (P < 0.05) positive correlations at two sites, especially with peat temperatures. Annual flux of methane is estimated to be 0.1-0.6 g C m-2 which, although low compared to other wetlands, becomes a substantial atmospheric contribution when the large area occupied by subarctic peatlands is taken into account. -Authorsmethane carbon dioxide peatlands fens