Cryoturbation, Peat Accumulation, And Gleying: Do These Processes Affect Soil Carbon Distribution Within Permafrost Profiles?

Abstract:

High latitude permafrost soils store an estimated 1300 Pg Carbon. Much of this soil carbon stock stock is vulnerable to decomposition with permafrost thaw. Permafrost processes strongly shape soil carbon dynamics through processes such as cryoturbation as well as impeding soil drainage and slowing the decomposition of soil organic matter. We hypothesized that different processes associated with permafrost would affect the vertical distribution of soil carbon as well as the depth of organic soils. We used an exponential depth model of vertical soil carbon distribution to calculate an empirical parameter, Z*, to compare among soils with varying permafrost processes. We found significant differences in vertical soil carbon distribution among the gelisol sub-orders. Gleying tended to reduce the soil carbon content at the surface mineral soils, which affected the vertical carbon profile. Unlike soils with higher mineral contents, less than 10% of histel profiles sampled showed a decrease in soil carbon content with depth due to the thick organic soil horizons. Together, these results show the promise and complexity of this simple approach to describing soil carbon stocks in permafrost soils.