Exchange of the Greenhouse Gases Methane and Nitrous Oxide Between the Atmosphere and a Temperate Peatland in Central Europe

Abstract

Fluxes of methane (CH4), nitrous oxide (N2O), and respired CO2 were measured with an automated chamber system (SIGMA) over the autumn of 2009 and growing season of 2010 in an undisturbed peatland with a floating carpet of mosses in western Poland. The main goal of our investigation was to deliver estimations of CH4 and N2O emission rates for this unique peatland type in Central Europe. CO2 and CH4 fluxes were also measured using a non-steady-state-flow-through manual chamber systems equipped with infrared gas analyzers and used to validate and adjust results obtained with the SIGMA system. The average methane fluxes for the 2009–2010 (excluding winter) period was 95.4 (±32.4) mg CH4-C m−2 d−1 resulting in a cumulative CH4 emission of 23.4 (±2.4) g CH4-C m−2 day growing season and 29.2 (±3.2) g CH4-C m−2 year−1 for the whole of 2010. The average seasonal N2O fluxes were 13.6 (± 28.2) μg N2O-N m−2 d−1. N2O fluxes were highly variable in time and sign (both uptake and emissions of N2O were observed during the accumulation periods). Maximum estimates of the annual emission rates of N2O were 0.004 g N2O-N m−2 year−1. Methane fluxes correlated significantly with the air and peat temperatures, but they were not dependent on water table depth. The N2O fluxes did not demonstrate a clear response to any environmental variables. Both CH4 and N2O emission rates were in the range of fluxes recorded in pristine peatlands in other climatic zones.