The influence of temperature and water table position on carbon dioxide and methane emissions from laboratory columns of peatland soils

SUMMARY Laboratory columns (80 cm long, 10 cm diameter) of peat were constructed from samples collected from a subarctic fen, a temperate bog and a temperate swamp. Temperature and water table position were manipulated to establish their influence on emissions of CO 2 and CH 4 from the columns. A factorial design experiment revealed significant ( P rising limb) was very pronounced for CH 4 emissions, attributed to a release of CH 4 stored in porewater and a lag in the development of anaerobic conditions and methanogenesis on the rising limb. Decreases in atmospheric pressure were correlated with abnormally large emissions of CO 2 and CH 4 on the falling limb. Peat slurries incubated in flasks revealed few differences between the three peat types in the rates of CO 2 production under aerobic and anaerobic conditions. There were, however, major differences between peat types in the rates of CH 4 consumption under aerobic incubation conditions and CH 4 production under anaerobic conditions (bog > fen > swamp), which explain the differences in response of the peat types in the column experiment.