Polar soils are of course found at the poles–that is, in the Arctic in the north as well as the Antarctic in the south. These regions include the continents of Antarctica, Alaska, northern Canada, Greenland, Norden (Lower Saxony, Germany), and the northern USSR. Permafrost is the layer of polar soil that is permanently frozen.
Geography
The following biogeoclimatic zones are recognised as having polar soils: tundra zone, polar desert zone, subpolar desert zone and cold desert zone. The Alpine zone is sometimes also included. Pedogenic processes are markedly different in these regions, as they are highly diverse and encompass both very wet and very dry soil conditions. Since soil is a result of the interaction among climate, vegetation, parent material, topography and time, the soil types found there are also very diverse.
Soil classification
There is no globally uniform soil classification. Of the polar nations the USA, Canada and Russia all have different national soil classification systems, but the World Reference Base for Soil Resources (under the auspices of the International Union of Soil Science) developed a classification system that enables comparison among national systems. Using this system, polar soils consist mainly of cryosols (a.k.a permafrost soil), podzols (characteristic of humid regions and strongly leached), histosols (an organic rather than a mineral soil), albeluvisols (iron depleted and very low in organic content) and gleysols (water saturated). Information on Antarctic soils is still lacking to a large degree.
Formation of polar soils
The major processes that form soil in the northern polar regions are mainly cryogenic, but also organic (e.g., peat formation), weathering, brunification (release of iron resulting in brown-colored soil), leaching, clay movement and destruction, podzolization, waterlogging (gleying), and salinisation. In the Antarctic, soil formation is mainly driven by weathering, resulting in brunification and salinisation.
Biota
Despite the cold, very dry or very wet and generally hostile conditions, polar soils do contain micro-organisms such as bacteria and nematodes. Vascular plants (moss, heath, grass) do occur, but algae and diatoms are usually the main constituents (Tedrow, J. C. F. 1968. Pedogenic gradients of the polar regions. Journal of Soil Science, 19:197–203). Sphagnum moss in particular seems to play a pivotal role in the development and dynamics of polar soils, and controls or modifies acidification and podzolization (Walker, M.D. 1996. Arctic soils and permafrost: Introduction. Arctic and Alpine Research 28(3)).
A major reference work for polar soils is the book “Soils of the polar landscapes” by J.C.F. Tedrow (1977).
