Difference in soil parameters between disturbed and undisturbed permafrost soil in Northwest Territories, Canada

As a result of strong climatic changes in arctic regions, permafrost areas are subject to substantial modifications. The matter raises global concerns due to the permafrost carbon climate feedback causing large amounts of Greenhouse Gases to be released into the atmosphere. Rising temperatures and climatic changes lead to permafrost disturbances developing distinct features termed thermokarsts. Thermokarsts evolve when ice-rich permafrost thaws and the soil collapses into the volume previously occupied by ice. In this study, the main focus lies on the thermokarst feature retrogressive thaw slump in the proximity of lakes. The differences in soil parameters between the Active Layer and permafrost and between disturbed and undisturbed permafrost ground are examined to give indications about the parametrical changes of permafrost soils in respect to climate change, permafrost disturbance and the consequent development of thermokarsts. Carbon, nitrogen, grain size, ice content and Radiocarbon dating analysis were conducted for this thesis. Carbon and Nitrogen are clearly depleted in the active layer compared to values in the cryotic ground and in disturbed compared to undisturbed ground. Further detailed analyses between sites reveal highly fluctuating dynamics and suggest that permafrost disturbance, thermokarst development and hence the release of Greenhouse Gases strongly depends on site-specific features such as vegetation cover, orientation, slope angle, water content and the local landscape history. Although thermokarsts and Greenhouse Gas release are known to increase in the future, how and to what extent controlling factors influence the soils development on a local scale is yet to be determined.