Controls on the storage of organic carbon in permafrost soil in northern Siberia

摘要

This research examined soil organic carbon (SOC), total nitrogen (TN) and aboveground phytomass carbon (PhC) stocks in two areas of the Taymyr Peninsula, northern Siberia. We combined field sampling, chemical and C-14 radiocarbon dating analyses with land cover classifications for landscape-level assessments. The estimated mean for the 0-100-cm depth SOC stocks was 14.8 and 20.8 kg Cm-2 in Ary-Mas and Logata, respectively. The corresponding values for TN were 1.0 and 1.3 kg Nm(-2). On average, about 2% only (range 0-12%) of the total ecosystem C is stored in PhC. In both study areas about 34% of the SOC at 0-100 cm is stored in cryoturbated pockets, which have formed since at least the early Holocene. The larger carbonitrogen (C/N) ratio of this cryoturbated material indicates that it consists of relatively undecomposed soil organic matter (SOM). There are substantial differences in SOC stocks and SOM properties within and between the two study areas, which emphasizes the need to consider both geomorphology and soil texture in the assessment of landscape-level and regional SOC stocks.