Fatty Acids Profile of Microbial Populations in a Mining Reclaimed Region Contaminated with Metals: Relation with Ecological Characteristics and Soil Respiration

Abstract

Mining activities cause drastic disturbances to terrestrial ecosystems affecting the landscape, soil organisms and quality. Ecosystem consists of aboveground and belowground components that interact and influence community and ecosystem level processes and properties. The present study aimed at determining the effects of mining on plant population diversity, genetic variation, soil respiration, and the abundance and composition of soil microbiota in Northern Ontario. Results from population diversity analyses revealed that species diversity and abundance were lower in sites close to smelters. The mean Shannon index value was significantly higher in reference sites compared to eroded/disturbed sites. Tree species richness was 4.7, 5.3, and 7.7 for eroded/disturbed, stable upland and reference sites, respectively. Molecular analysis revealed no differences in genetic variation among plant populations from eroded/disturbed, stable upland and reference sites for the three hardwood species. Soil respiration and PLFA analysis revealed that respiration, total microbial biomass, fungal and bacterial abundances were significantly lower in eroded/disturbed sites compared to reference sites. Overall, microbial community biomass, respiration and fungal abundance significantly increased with higher plant diversities as did soil C and N concentrations. The ratios between fungi and bacteria biomass and among other PLFA measures were extremely low suggesting that the targeted region is still under environmental stress.