Morphology and properties of permafrost-affected soils under different tundra vegetation in central Spitsbergen

The main aim of this study was to determine the morphology, physical and chemical properties of permafrost-affected soils under different types of tundra in the central part of Spitsbergen. This is a preliminary part of detailed studies focused on the relationship between tundra vegetation and permafrost-affected soils in the Spitsbergen. The obtained results indicate that all the studied soils represent an early stage of formation and the main soil-forming process present in these soils is cryoturbation. Most of the studied soils are shallow and contain a high content of coarse rock fragments. Tundra vegetation type plays controlling role in the development and structure of surface soil horizons. All the studied soils are characterized by loamy texture and acidic or slightly acidic reaction, and these properties are not very different under various tundra vegetation types. The contents of soil organic matter are strongly dependent on the type of tundra vegetation. The highest soil organic matter content occurs at sites with well-developed vegetation such as heath and wet moss tundra. The high carbon-to-nitrogen ratio for the surface soil horizons of the majority of the studied soils indicates that organic matter is poorly decomposed under all the studied tundra vegetation types. This is most likely related to low activity of soil microorganisms in the harsh High Arctic environment. However, the lowest carbon-to-nitrogen ratio was noted for surface soil horizons at sites covered with Arctic meadow, and this indicates that there occur the optimum conditions for soil organic matter decomposition.