Soil Organic Carbon Stock in the Glacier Foreland of Midtre Lovenbreen, in the High Arctic

Abstract

Global warming leads to rapid melting of glaciers in the high Arctic, exposing new soil surfaces. Soil organic carbon (SOC) accumulation in the proglacial environment has initiated along soil chronosequence after microorganisms and plants have settled down. SOC accumulation is affected not only by soil age but also by several environmental factors, however, those influences have not yet been thoroughly investigated. Hence, we are aiming to estimate the SOC stock in the glacier foreland of the Midtre Lovenbreen, Spitsbergen, Norway (79°N, 12°W) with a consideration of the deglaciated years, microtopography, runoff activity, etc. A total of 36 sampling points were selected to collect soil for 0-30 cm depth, and vegetation was surveyed from 93 points. The SOC stock was estimated from the concentration of SOC and bulk density calculated from soil texture. The SOC content among 5-10, 10-20, and 20-30 cm did not differ, and bulk density through all depths did not vary either. Thus, SOC stock was closely related to the SOC content of the top soil (0-5 cm). Among several vegetation related parameters, the sum of vascular plants' frequency showed the highest correlation with the SOC content of top soil and SOC stock. However, intestingly, there was no correlation between the SOC stock and soil age. The active and intermittent runoff sites showed significantly lower SOC content compared to no runoff sites. Glacier/snow meltwater would have washed out previously established vegetation and accumulated SOC. We are currently using multivariate statistics to deal with quantitative and qualitative data, and are scrutinizing the relationship between SOC stock and environmental variables acquired from DEM and remote sensing data in depth as a next step. Through understanding the relationship between SOC content/stock and environmental parameters, there is a possibility to quantify and predict SOC distribution by observing vegetation distribution and extracting specific environmental factors.