Functional diversity and community structure of microorganisms in uncontaminated and creosote-contaminated soils as determined by sole-carbon-source-utilization

Functional diversities of microorganisms from uncontaminated and creosote-contaminated soils were assessed using sole-carbon source-utilization patterns. The microorganisms were extracted from soil samples and inoculated into Gram-negative Biolog plates incubated at 23°C. Measurement of Shannon diversity, richness, and evenness indices, principal component analysis (PCA), and colour development rank (CDR) plots were based upon substrate utilization. Calculations incorporated data from both the 95 regular Gram-negative Biolog microplate wells and a selection of 23 carbon substrates that are included on Biolog Ecoplates. There did not appear to be significant differences in Shannon diversity and richness indices, PCA, or CDR plots between aminated and creosote-contaminated soils. Significant differences in Shannon diversity and evenness indices that were apparent with the use of the 23 ecologically relevant microplate wells were mostly absent based on calculations that incorporated the regular 95 Gram-negative Biolog microplate wells. Resolution of microbial communities by PCA, however, appeared to be reduced by the use of the 23 Biolog microplate wells compared to the regular 95 carbon sources.