Sulphur in the Arctic environment (2): results of multi-medium regional mapping

Abstract

The regional distribution patterns of S in terrestrial moss and in the O-, B-, and C-horizon of podzols have been studied in a 188,000 km 2 area in Arctic Europe with both, large natural (marine aerosols) and anthropogenic gradients of S-input. Although the existence of a pollution source is visible in the S-maps for moss, the S-deposition gradient is not depicted. The concentration of S in moss is not at all influenced by input of marine aerosols. In contrast, the O-horizon of podzols shows a coastal enrichment of S but does not reflect the anthropogenic input. Even the coastal pattern visible in the map of S in the O-horizon is, however, not linked to the input of SO 4 2− via sea spray but is rather caused by low litter decomposition rates due to low temperature, increasing total S and decreasing mobile S near coast. S-concentrations as observed in the deeper soil horizons are only locally influenced by both anthropogenic and marine input of S. These results suggest that in undisturbed terrestrial environments no mechanism exists for enriching an additional input of S from anthropogenic or natural sources. A very high local variability in the four sample materials points to small-scale local processes being most important for the observed S-concentrations.