Processes influencing the chemical composition of the O-horizon of podzols along a 500-km north-south profile from the coast of the Barents Sea to the Arctic Circle

Large-scale regional processes influencing the chemical composition of the O-horizon of podzols have been studied along a 500-km-long north-south profile from the coast of the Barents Sea in N-Norway (North Cape) to the Arctic Circle in northern Finland. Precipitation (composition and amount) appears to be the major factor determining the chemical composition of the O-horizon, followed by vegetation (especially the change from the tundra and subarctic birch forest to the boreal forest zone). This results in distance to coast having an important influence on pH and concentrations and fluxes of over 20 elements in the O-horizon along this profile. A high local variability of several elements, especially some important nutrients, indicates that other small-scale processes also play an important role. While there are signs that elements displaced from surficial soils accumulate in the C-horizon, the composition of the soil parent material (bedrock, Quaternary drift) has relatively little influence on the chemistry of the O-horizon for most elements. (C) 2000 Elsevier Science B.V. All rights reserved.