ITS sequencing of petroleum contaminated and uncontaminated soils from the Kimberley Region, Australia

The Kimberley region of Western Australia is a National Heritage listed region that is internationally recognised for its environmental and cultural significance. However, petroleum spills have been reported at a number of sites across the region; representing a considerable environmental concern. The region is also characterised as having low soil nutrients, high temperatures and monsoonal rain, all of which may limit its potential for natural biodegradation of petroleum to occur. Therefore, this work evaluated the effect of legacy petroleum hydrocarbons on the indigenous soil microbial community (Archaea, Bacteria and Fungi) across three sites in the Kimberley region. At each site, soil cores were removed from contaminated and control areas and analyzed for total petroleum hydrocarbons, soil nutrients, pH and microbial community profiling (using DNA and 16S rRNA and ITS sequencing on the Illumina MiSeq Platform). The presence of petroleum hydrocarbons decreased microbial diversity across all kingdoms, altered the structure of microbial communities and increased the abundance of putative hydrocarbon degraders (e.g. Mycobacterium, Acremonium, Penicillium, Bjerkandera and Candida). Microbial community shifts from contaminated soils were also associated with an increase in soil nutrients (notably PO4 and S). Our study highlights the long-term effect of legacy hydrocarbon spills on soil microbial communities and their diversity in remote, infertile monsoonal soils, but also highlights the potential for natural attenuation to occur in these environments.