9. Cryosols of Antarctica

Only 0.35 % of Antarctica is ice-free, amounting to an area of 49,500 km². There are three distinct climatic zones in Antarctica. The western Antarctic Peninsula and the offshore islands (South Shetland and South Orkney Islands) have a subantarctic maritime climate with comparatively mild temperatures and abundant precipitation, including rainfall. Coastal East Antarctica has cooler temperatures and less precipitation, all of which falls as snow. The inland mountains feature hyperarid and hypergelic conditions. These climate differences are reflected in active-layer thickness and mean annual ground temperatures, which are greatest in maritime Antarctica and least in the mountains. Birds, especially large penguin colonies, play an important role in soil formation and in the ability of sites to become colonized by vegetation. Whereas soils in maritime and East Antarctica tend to be of Last Glacial Maximum or Holocene in age, soils of inland mountains commonly range from mid-Pleistocene to Miocene in age.

The climatic zonation is reflected in the nature of the soils. The amounts of silt and clay, organic C, total N, extractable P, and soil moisture and soil temperature decline from the West Antarctic Peninsula to East Antarctica and then to the inland mountains. Whereas soils of maritime and East Antarctica are often very strongly acidic and low in base cations and soluble salts, soils of the inland mountains are alkaline, strongly base saturated, and contain abundance salts.