Resistance and resilience of zinc tolerant nitrifying communities is unaffected in long-term zinc contaminated soils

Zinc (Zn) tolerant nitrifying communities were previously identified in soil samples of a long-term Zn contaminated transect towards a galvanised pylon. We questioned whether Zn tolerance increased the vulnerability of the nitrifying communities to stressors. The influence of pesticide addition, freeze-thaw or dry-wet cycles on the soil nitrification ('functional stability') was assessed in a series of these soils representing a Zn contamination and Zn tolerance gradient. The immediate effect of the stressors to the nitrification ('resistance') and the residual effect after 3 weeks incubation ('resilience') were determined. Our results show that neither resistance nor resilience to these stressors was affected by adaptation of the nitrifying communities to elevated Zn concentrations in the long-term contaminated soils. (c) 2007 Elsevier Ltd. All rights reserved.