ISOTOPIC SIGNATURE OF METHANE EFFLUX FROM SOIL SURFACE OF SIBERIAN ARCTIC AND SUB-ARCTIC ECOSYSTEMS

We investigated isotopic signature of methane efflux from soil surface of Siberian arctic and sub-arctic ecosystems in sites in Siberia. In the boreal ecosystem of the Tura site (64 degrees 15'N, 100 13'E) the delta C-13 signature of methane (-43%o for south facing slope and -35%o from north facing slope) showed low methane production potential of investigated soils. Two years of monitoring of the delta C-13(CH4) signatures from surface of ice-wedge polygon of Samoylov island (72 degrees 22'N, 126 degrees 28'E) showed that the delta C-13 signature were different regarding to temperature and precipitation. The mean of delta C-13(CH4) emitted from the polygon wall ranged from 72.5 +/- 1.9%. to-47.3 +/- 1.5%. The same for polygon center ranged from-67.1 +/- 2.0% to-62.4 +/- 1.7%. Almost no difference between delta C-13(CH4) signature of years observed could mean that conditions for methane production are possibly quite stable. With respect to methane emission both permafrost ecosystems are thus very contrasting.