Bacterial Diversity as a BioMarker of Soil Health

由于它们与土壤污染物密切相关，我们假设它们的多样性

Because of their intimate association with soil contaminants, we HYPOTHESIZE that the diversity [measured as richness and evenness) of the metabolically-active fraction of the soil bacterial community serves as a biomarker of the threat to human health from PAHs and heavy metals polluting Superfund sites. To challenge this hypothesis, we will address three SPECIFIC AIMS: (1) Identify correlations between the results of molecular biology-based measures of bacterial diversity and analytical measures of PAHs and heavy metals during soil ageing and bioremediation of mock Superfund sites; (2) Demonstrate novel molecular biology-based assays to assess the diversity of the metabolically active fraction of the bacterial community in situ; and (3) Demonstrate ecological models to predict soil bacterial community diversity under the influence of mixtures of heavy metals and PAHs. The APPROACH includes: (i) operating mock Superfund sites; (ii) T-RFLP and (iii) whole cell FISH to measure bacterial diversity; (iv) identifying predominant bacterial populations using clone libraries; (v) evaluating the impact of PAH and heavy metals on ribosome genesis; (vi) identifying heavy-metal responsive genes using microarrays; (vii) evaluating metagenomics of PAH degradation; (viii) evaluating real-time PCR to quantify heavy-metal and PAHresponsive genes; (ix) adapting ecological models to predict bacterial diversity; (x) comparing experimental measures of diversity with model predictions; and (xi) evaluating optimum nutrient amendments predicted with the resource-ratio theory. This project is INNOVATIVE because we are using molecular biology-based measures of bacterial diversity as a diagnostic tool to predict the threat to human health at Superfund sites (i.e., bacteria as sentinels for pollution). We expect that the positive findings of this study can be used to evaluate the potential for success of bioremediation strategies as well as to establish an effective endpoint of bioremediation (i.e., when appropriate bacterial diversity has been re-established and the threat to human health significantly reduced).