Soil organic carbon stocks in a mountain permafrost area with extensive solifluction (Disko Island, west Greenland)

This study presents a detailed soil organic carbon (SOC) inventory for the Blæsedalen catchment, Disko Island. The study area has a mountainous setting (sea level to c. 800-m elevation), largely dominated by continuous permafrost. A total of twenty-eight soil profiles were sampled, with additional plant cover observations at eighteen sites. The landscape-level mean SOC 0- to 100-cm storage based on land cover upscaling is 4.07 ± 0.74 kg C m−2. These stocks are largely found in the vegetated zone below 400-m elevation. Due to generally deep active layers, only about 4 percent of the total SOC stock is stored in the permafrost layer. An additional upscaling using landform criteria results in a mean stock of 4.01 ± 1.21 kg C m−2. A prominent landform class is “solifluction areas,” which occupies 18 percent of the total study area but represents 56 percent of the total SOC stock. This class has a highly variable SOC 0- to 100-cm stock (0.86–25.5 kg C m−2), but the mean of 12.6 kg C m−2 is much higher than the landscape average. Both landscape-level mean SOC 0- to 100-cm stock estimates in this study are similar, but land cover provides more constrained SOC ranges than landform upscaling.