ИСТИНА

Intensive air pollution has led to severe damage of forest ecosystems, disturbance of soil forming processes and changes of carbon pools in soils near the nickel-copper smelter in the Kola Subarctic. The prevailing in the region thin sandy acid podzols are poor in nutrients and organic matter. In background areas iron-illuvial podzols under pine forests have low carbon pools (about 3 kg C/m2) while humus-illuvial podzols under birch forests are enriched by carbon (about 5 kg C/m2). Soil carbon pool gradually rises towards the pollution source and reaches the highest values (about 10 kg C/m2) in soils of barren lands closely to the smelter. The gradual increase in soil carbon pools during technogenic digression of forest ecosystems is associated mainly with progressive defoliation and retarded decomposition of plant litter on the soil surface, resulting in the accumulation of organic matter in humus layer. This is followed by intensive migration of carbon in the form of fulvic acid and labile forms down the profile, while humic acids are inactive and stable.