Effects of artificial acid rain on microbial activity and biomass

The emission of air pollutants which form acid components in rain and snow represents a threat to natural ecosystems. Increased leaching of nutrients from soils (ABRAHAMSEN et al. 1976b), decreased pHvalues in lakes and changes in fish populations (SCHOFIELD 1976) have been suggested as some of the consequences of the increased acidity of rain. Scandinavian coniferous forests are very stable ecosystems, and dramatic short-term effects due to acid rain are hardly to be expected. To simulate long-term effects, artificially acidified rain may be used. We report here decreased microbial activity and biomass in a Norwegian forest soil treated with artificially acidified rain