Temperature response of soil organic matter mineralisation in arctic soil profiles

摘要: Soil organic matter (SOM) in arctic and boreal soils is the largest terrestrial reservoir of carbon. Increased SOM mineralisation under increased temperature has potential to induce a massive release CO2. Precise parameterisation response temperatures therefore crucial for correctly simulating our future climate. Here, we investigated eight soil profiles Norway, Svalbard Russia. Samples were collected at two depths from both mineral soils, which affected or not by permafrost incubated 91 days 4, 8, 12, 16 °C. Temperature was through parameters derived simple exponential model: intensity mineralisation, α, sensitivity, Q10. For each sample, quality 13C-NMR, whereas bacterial fungal community structure characterised T-RFLP ARISA fingerprints, respectively. When estimated whole incubation period, α proved be higher deep samples than shallow active layer ones due presence transient flushes soils. At end after mineralization had passed, neither nor Q10 (averaging 1.28 ± 0.07) seemed type (organic vs soil), site, depth permafrost. composition microbial on contrary where site type. Our results suggest that contain small pool fast cycling carbon, quickly depleted thawing. Once flush relatively homogenous among sample types, suggesting use single sensitivity parameter land surface models decomposition permafrost-affected justified.