Exciting PhD project:
An opportunity exists for a motivated PhD-student to join the Microbes and Heavy Metal Group at University of Adelaide to study the:
Geomicrobiology of gold from arid and subarctic North America
Supervisors: Frank Reith, Jeremiah Shuster (both University of Adelaide), Erik Melchiorre (California State University)
The biogeochemical cycle of gold is driven by geomicrobial processes mediating the dispersion and reconcentration of gold in Earth surface environments. Biogeochemical cycling of gold has been demonstrated in present-day semi-arid, (sub)-tropical and temperate environments, whereby biofilms on gold-bearing mineral and gold-particle surfaces drive the dispersion and reconcentration of gold, thereby (trans)forming the particles. If biogeochemical cycling of gold and associated microbial communities in arid or arctic environments, where air temperatures can reach+40°C or -40°C and soils are very dry or remain frozen for much of the year, respectively, are largely unknown.
Therefore, the aims of this study are to assess:
- if biofilms are present on placer gold particles from Arizona, California, the Yukon and Alaska;
- the phylogenetic and putative functional composition of bacterial biofilm communities;
- the presence of secondary gold morphotypes indicative of biogeochemical gold cycling.
To achieve this, gold particles from a range placer sites in Arizona, California, the Yukon and Alaska will studied using a combination of culture dependent and independent techniques, e.g., Illumina Miseq next generation sequencing and high density functional microarrays (GeoChip). Advanced micro-analytical techniques will be applied, including field emission gun-scanning electron microscopy, focused ion beam-scanning electron microscopy coupled with energy dispersive x-ray spectroscopy, and electron microprobe analyses.
This project is part of a large suite of studies assessing all aspects of biogeochemical gold cycling around the world. Studies are currently underway with samples from South Africa, New Zealand, the UK, Switzerland, Germany, Brazil and The Philippines These provide a molecular-level understanding of the bio(geo)chemical processes underpinning gold mobilisation, dispersion and re-concentration in many environments. Ultimately the implementation of a comprehensive global biogeochemical model for gold cycling, describing its distribution, speciation and bio(geo)chemical turnover in Earth surface environment is the aim of this research.
The successful candidate will have advanced skills in molecular microbiology and/or micro-analytical techniques, experience in a clean laboratory environment, be an excellent writer and communicator, and be high highly self-motivated and organised.
Prospective domestic and international candidates can contact A.Prof. Frank Reith to discuss the project as well as scholarship opportunities.