Arctic Permafrost Soils

Abstract

Arctic soils are associated with permafrost and their properties result dominantly from the action of cryogenic processes. These processes are driven by the presence and mobility of unfrozen soil water as it migrates along the thermal gradient towards the frozen front in the frozen system, feeding the ice bodies in the soil. These cryogenic processes result in the formation of various patterned ground types on the soil surface. Within the soil, they give rise to unique macromorphological features such as cryoturbated soil horizons and granular, platy, blocky and massive soil structures and micromorphological features such as orbicular, suscitic, conglomeric, lenticular, granic and blocky fabrics with sorted and oriented skeletal grains. The pH of Arctic soils varies greatly and, in most cases, depends on the chemistry of the parent materials. Although these soils are generally low in nutrients, especially nitrogen, cryoturbated mineral soils and organic soils contain large amounts of carbon and act as carbon sinks.