Temperature sensitivity of decomposition in a boreal mixed mire in northern Sweden

Carbon accumulation in soils constitutes a significant sink for carbon. How the climate change with increasing temperatures will affect the soil carbon storage represents uncertainty of the predictions in the climate change ecosystem feedback mechanisms. In this study the temperature impact on the decomposition of the large carbon pools in peatlands was investigated. Peat cores from different microtopographic units in a boreal oligotrophic minerogenic mire in northern Sweden were collected from in three depths (5-10, 10-15 and 15-20 centimeters below the surface). The samples were incubated at four temperatures: 4, 9, 14 and 19°C and the heterotrophic respiration (CO2- production) was measured hourly or 37 days. Unexpectedly, basal respiration did not show any correlation with temperature. However, the exponential increase in respiration (µ) was correlated with temperature: i.e. giving Q10 values between 2 (SE +/- 0.36) and 5 (SE +/-1.05). Soil depth or vegetation covers did not affect temperature response (Q10) of µ. The substrate induced respiration (SIR) did not occour but for a few of the samples. The conclusion from this study is that degradation of peat seams not be affected by a temperature increase. The addition of glucose, nitrogen and phosphorus increased with increasing temperature with a Q10 value as expected