CO2 fluxes and evaporation on a peatland in the Netherlands appear not affected by water table fluctuations

The effect of shallow water table fluctuations on the evaporation and CO2 fluxes in a peatland is investigated. The fluxes of evaporation and net ecosystem exchange of carbon were measured from mid-spring to the end of summer in 2005 and 2006 and simulated independently with process models. The observed and modelled data were then compared along a gradient of water levels. Any variation along the gradient would imply an influence of the water table on the flux. It became evident that changes in the water table had no effect on the evaporation and CO2 fluxes of the peatland. A probable cause could be the high water content of the soil, even for the low water tables, and the stable thermal conductivity of the soil. This study has implications for current land use management, which is aimed at reducing CO2-emissions. Regulations are currently concerned with water table while this study shows that soil water content should be focused on as well.