Effect of heavy metals on substrate utilization pattern, biomass, and activity of microbial communities in a reclaimed mining wasteland of red soil area

The microbial biomass, basal respiration, and substrate utilization pattern in a copper mining wasteland of red soil area, southern China, were investigated, and indicated that soil microflora were obviously affected by heavy metals. Microbial biomass and basal respiration were negatively affected by comparatively high heavy metal levels. Two important microbial ecophysiological parameters, namely, the microbial biomass C (Cmic)/microbial biomass N (Nmic) ratio and the metabolic quotient (qCO2) were significantly correlated to heavy metal stress. There was a significant decrease in the Cmic/Nmic ratio and an increase in the metabolic quotient with increasing metal concentration. Multivariate analysis of Biolog data for sole carbon source utilization pattern demonstrated that heavy metal pollution had a significant impact on microbial community structure and functional diversity. All the results showed that soil microbiological parameters could have great potential as sensitive, effective, and liable indicators of the stresses or perturbations in soils of mining ecosystems.