Emissions of CO2, CH4 and N2O from undisturbed, drained and mined peatlands in Estonia

The aim of this study is to estimate emissions of greenhouse gases CO2, CH4 and N2O, and the effects of drainage and peat extraction on these processes, in Estonian transitional fens and ombrotrophic bogs. Closed-chamber-based sampling lasted from January to December 2009 in nine peatlands in Estonia, covering areas with different land-use practices: natural (four study sites), drained (six sites), abandoned peat mining (five sites) and active peat mining areas (five sites). Median values of soil CO2 efflux were 1,509, 1,921, 2,845 and 1,741 kg CO2-C ha(-1) year(-1) from natural, drained, abandoned and active mining areas, respectively. Emission of CH4-C (median values) was 85.2, 23.7, 0.07 and 0.12 kg ha(-1) year(-1), and N2O-N -0.05, -0.01, 0.18 and 0.19 kg ha(-1) year(-1), respectively. There were significantly higher emissions of CO2 and N2O from abandoned and active peat mining areas, whereas CH4 emissions were significantly higher in natural and drained areas. Significant Spearman rank correlation was found between soil temperature and CO2 flux at all sites, and CH4 flux with high water level at natural and drained areas. Significant increase in CH4 flux was detected for groundwater levels above 30 cm.