Substrate Addition Enhances the Adaptation Rate of Nitrifying and Denitrifying Communities in Zinc Contaminated Soils

Abstract

Previous studies showed that nitrifying and denitrifying soil microbial communities are able to adapt to increased Zn concentrations. A striking difference in adaptation rate was observed between denitrification (within 3 months after contamination) and nitrification (not within 6 months). It is hypothesized that this difference is related to the growth rate of the microbial communities. Experiments were conducted to determine the adaptation rate of both processes in artificially zinc contaminated soils as affected by growth stimulating substrate additions (NH4+ and organic matter). Without substrate additions, no adaptation of nitrification was observed in 12 months whereas denitrification activity restored during that period. Substrate addition enhanced the adaptation rate of both processes within 6 months of incubation.status: publishe