Microbial and Plant Diversity and Correspondence with Soil and Environmental Properties on Brownfields in a Semi-Arid Area

Background/Question/Methods

Certain fungi, including root-associated fungi, are capable of degrading organic contaminants of concern and enhancing the bio and phyto-remediation of metal and mixed contaminated soils. We assessed microbial and plant diversity on contaminated sites in a semi-arid region with the goal of identifying locally adapted species tolerant of the mixed organic and inorganic contaminated soils and the hot and dry climate found regionally. Eight contaminated sites (known as brownfields) across semi-arid Southern California were surveyed, species with potential application in biological remediation were identified and the environmental conditions and soil biogeochemical factors that correlate with their abundance and diversity was assessed. Soil physico-chemical properties, environmental variables such as soil moisture, and microbial diversity were analyzed and the 16S, SSU and ITS2 regions of DNA extracted from interspace and rhizosphere soils were sequenced to identify bacterial and fungal, including mycorrhizal, diversity and abundance. Plants were identified, sampled and microwave digested before metal-uptake analysis using ICP-MS.

Results/Conclusions

Several native plant hyperaccumulators of metals of concern were identified. Fungi from the Ascomycota including known petroleum-degrading fungi were dominant across all sites. A CCA was run to analyze the correspondence between soil physical and chemical properties including contaminant type and concentration, environmental variables, and fungal diversity was undertaken. The results presented aim to elucidate which soil and environmental variables are correlated with the fungal diversity on contaminated sites and help unravel the interactions between mycorrhizas, other fungi, and plants in these contaminated environments.