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°15'N, 100°13'E) the d¹³C signature of methane (-43‰ for south facing slope and - 35‰ from north facing slope) showed low methane production potential of investigated soils. Two years of monitoring of the d¹³C_CH4 signatures from surface of ice-wedge polygon of Samoylov island (72°22'N, 126°28'E) showed that the d¹³C signature were different regarding to temperature and precipitation. The mean of d¹³C_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 d¹³C_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. [ABSTRACT FROM AUTHOR]