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Professor Gordon Southam

Professor

School of the Environment
Faculty of Science

Professor

W.H. Bryan Mining and Geology Research Centre
Sustainable Minerals Institute
g.southam@uq.edu.au
+61 7 336 58505

Overview

Professor Southam is a Professor in Geomicrobiology. He is an interdisciplinary researcher who crosses the traditional boundaries between biological and geological sciences to examine bacterial transformations of materials composing the earth’s crust, and the impact these transformations have had over geologic time. Field sites have ranged from Yellostone National Park, to Axel Heiberg Island in the Canadian high arctic, to the ultradeep gold mines in the Republic of Southam Africa (up to 4 km below land surface, to the Amazon Basin. Following his appointment as a Canada Research Chair in Geomicrobiology and Director of Environment and Sustainability at Western University, Canada, Dr. Southam has moved to the University of Queensland where he is leading projects on:

Mineral carbonation, using acid generating bacteria to enhance weathering of ultramafic mine waste, promoting mineral carbonation (CO2 sequestration);

Bioremediation of iron mine sites, by enhancing the biogeochemical cycling of iron to promote the formation of ferruginous duricrusts (canga), and

Bioleaching, focussing on low-grade copper in arid through tropical ecosystems (Australia and Brazil);

Gold exploration, examining the fundamental roles that bacteria play in catalysing the formation of placer gold.

Research Interests

  • Life in Extreme Environments / Bacterial Fossilisation
    The growth of bacteria in extreme environments combined with their metal-reactive cell envelopes often results in their fossilization in these environments. The preservation of cellular and molecular biomarkers in ancients Earth systems can teach us about the evolution of life on Earth and their influence on lithosphere-hydrosphere-atmosphere system processes. The diversity of life’s extremes is also intriguing with the respect to the possibility of life occurring elsewhere in the solar system, e.g., Mars. Current research is improving our understanding of the fundamental processes responsible for fossilisation in contemporary and ancient Earth environments, e.g., the biooxidation of iron and subsequent per-mineralization in arid, acid environments.
  • Bioleaching
    Present day mining operations have reached geological scales. Entire mountains are being mined, crushed, sorted, transported, smelted, and consumed by an ever-increasing human population. In parallel, new landscapes are being created with the waste products, often low-grade or lesser-quality ores. Extracting resources from these low-grade ores presents major challenges that we propose to address by determining the critical steps controlling the biooxidation of copper sulphides, in particular, chalcopyrite. The solubilisation, speciation, fractionation and precipitation of many metals and metal ions are directly and indirectly influenced by microbial activity (Southam & Saunders, 2005). The significance of microbial catalysis is highlighted in Enders et al. (2006) where we demonstrated the role of bacteria in the supergene weathering of Fe and Cu at Morenci, AZ, the largest copper mine in North America, producing 1,000 tonnes of Cu/day through bacterial leaching. The biogeochemical oxidation of iron and sulphur in pyrite enhances the dissolution of copper, which can lead to supergene enrichment over geologic time scales (Enders et al., 2006) and can be exploited for the recovery of Cu through bioleaching.
  • Canga
    Supergene enriched iron-ore deposits are typically protected by a goethite-cemented ferruginous duricrust layer referred to as canga. The formation of canga horizons has been linked to the biogeochemical cycling of iron. Incredibly, no work on the biogeochemistry of canga has been done. These supergene Fe-ore systems are actively forming in the tropics by weathering of banded iron formations. Canga forms extensive deposits blanketing ancient erosion surfaces, is tough, moderately hard, well consolidated, permeable and very resistant to erosion and chemical weathering, protecting the relatively soft enriched iron ore below. This protective canga horizon is therefore, essential to supergene iron ore enrichment and formation of high-grade iron ore. Canga hosts unique, endemic open herbaceous-shrubs, dominated by hemicryptophytes that are in dramatic contrast to the surrounding vegetation, especially in the Carajás and Quadrilátero Ferrífero regions of Brazil where tropical rainforests surrounds these ‘islands’ of canga. Effective restoration of mined iron sites to re-establish these unique ecosystems requires the re-precipitation of canga, a process never previously attempted. Studying the biology of these systems, i.e., the biogeochemical cycling of iron and the identification of novel biotechnologically important organisms is essential for the success of this project.
  • Gold
    Gold is a relatively inert metal, yet it is often found as concentrated placer deposits. These deposits are unusual because the gold nuggets recovered from them can be larger than the gold found in the source rock. Using gold-thiosulfate, the gold complex important in base metal sulphide systems, we demonstrated that thiosulfate-oxidising and thiosulfate-reducing bacteria can produce octahedral gold, similar to the interaction between bacteria and gold(III)-chloride complexes. Synchrotron results have begun to elucidate the mechanism of octahedral gold formation, demonstrating that organosulphur-Au(I) compounds are the intermediate complex produced during the reaction between bacteria and gold(III) chloride. Both complexes are important to the biogeochemical cycling of gold in natural systems. Recent evidence of biofilms on gold grains demonstrates that biogeochemical processing of gold is occurring in nature and is therefore, fundamentally important to mineral exploration programs.
  • Mineral Carbonation
    Ultramafic and mafic mine tailings are a potentially valuable feedstock for carbon mineralization that should be used to offset carbon emissions generated by mining. Passive carbon mineralization is occurring at the abandoned Clinton Creek asbestos mine, and the active Diavik diamond and Mount Keith nickel mines. Microbially mediated processes have the potential to accelerate carbon mineralization to create economically viable, large-scale carbon dioxide fixation technologies that can operate at ambient temperature and atmospheric pressure. Bioleaching of magnesium silicates (serpentine, olivine); increasing the supply of CO2 via heterotrophic oxidation of waste organics; and biologically induced carbonate precipitation, as well as enhancing passive carbonation through tailings management practices and use of CO2 point sources. With the aim of developing carbon-neutral mines, tailings storage facilities could be geoengineered as habitats for microbial communities that accelerate carbon mineralization.
  • Methanogenesis
    The methanogenesis project aims to determine how microorganisms degrade coal and to demonstrate the feasibility of producing biogenic methane from waste coal in an abandoned mine. Through this project, we will conduct a microbial survey of at least two Bowen Basin coal mines to identify the organisms that thrive where coal is the sole source of organic carbon. The future methane production of these mines will be determined in a laboratory trial using two different chemical regimes, one possessing a gradient from aerobic to anaerobic conditions and in the other solely anaerobic. Finally, coal will be separated into physical and chemical fractions to determine why coal degradation by anaerobic organisms is limited by the hydrolysis step during methane production.

Qualifications

  • Doctor of Philosophy, University of Guelph
  • Bachelor (Honours) of Science (Advanced), University of Guelph

Publications

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Grants

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Supervision

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Publications

Featured Publications

Book Chapter

  • Microbial Mining

    Southam, Gordon (2024). Microbial Mining. Heavy Metal. (pp. 211-218) Cambridge, UK: Open Book Publishers. doi: 10.11647/obp.0373.28

  • Sulfide Oxidation

    Southam, Gordon (2023). Sulfide Oxidation. Encyclopedia of Astrobiology. (pp. 2930-2932) Berlin, Heidelberg: Springer Berlin Heidelberg. doi: 10.1007/978-3-662-65093-6_5421

  • Applications of scanning electron microscopy in geomicrobiology

    Shuster, Jeremiah, Southam, Gordon and Reith, Frank (2019). Applications of scanning electron microscopy in geomicrobiology. Analytical geomicrobiology: a handbook of instrumental techniques. (pp. 148-165) edited by Janice P. L. Kenney, Harish Veeramani and Daniel S. Alessi. Cambridge, United Kingdom: Cambridge University Press.

  • Applications of transmission electron microscopy in geomicrobiology

    Shuster, Jeremiah, Reith, Frank and Southam, Gordon (2019). Applications of transmission electron microscopy in geomicrobiology. Analytical geomicrobiology: a handbook of instrumental techniques. (pp. 166-186) edited by Kenney, Janice P. L, Veeramani, Harish and Alessi, Daniel S. Cambridge, United Kingdom: Cambridge University Press. doi: 10.1017/9781107707399.006

  • Geomicrobiology of sulfide mineral oxidation

    Nordstrom, D. Kirk and Southam, Gordon (2019). Geomicrobiology of sulfide mineral oxidation. Geomicrobiology: interactions between microbes and minerals. (pp. 361-390) edited by Jillian F. Banfield and Kenneth H. Nealson . Berlin, Germany: De Gruyter Mouton. doi: 10.1515/9781501509247

  • Geology, life, and habitability

    Southam, G., Westall, F. and Spohn, T. (2015). Geology, life, and habitability. Treatise on geophysics: second edition. (pp. 473-486) edited by Gerald Schubert. Amsterdam, The Netherlands: Elsevier. doi: 10.1016/B978-0-444-53802-4.00175-5

  • The Early Record of Life

    Westall, Frances and Southam, Gordon (2013). The Early Record of Life. Archean Geodynamics and Environments. (pp. 283-304) edited by Keith Benn , Jean‐Claude Mareschal and Kent C. Condie. Washington, D. C., United States: American Geophysical Union. doi: 10.1029/164GM18

  • Biosynthesis of Gold Nanoparticles: A Review

    Lengke, Maggy F., Sanpawanitchakit, Charoen and Southam, Gordon (2011). Biosynthesis of Gold Nanoparticles: A Review. Metal nanoparticles in microbiology. (pp. 37-74) edited by Mahendra Rai and Nelson Duran. Berlin Heidelberg, Germany: Springer-Verlag. doi: 10.1007/978-3-642-18312-6_3

  • Geology, Life and Habitability

    Southam, G. and Westall, F. (2007). Geology, Life and Habitability. Treatise on Geophysics. (pp. 421-437) Elsevier. doi: 10.1016/B978-044452748-6.00164-4

  • 10.12 - Geology, Life and Habitability

    Southam, G. and Westall, F. (2007). 10.12 - Geology, Life and Habitability. Treatise on Geophysics: Volume 1-10. (pp. 421-437) Elsevier. doi: 10.1016/B978-044452748-6.00164-4

  • The early record of life

    Westall, Frances and Southam, Gordon (2006). The early record of life. Geophysical Monograph Series. (pp. 289-304) Blackwell Publishing Ltd. doi: 10.1029/164GM18

Journal Article

Conference Publication

Other Outputs

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

  • Investigation of the interface between electrochemically-active microorganisms and metals

    Doctor Philosophy — Principal Advisor

  • Acid Mine Drainage Passive Treatment Method Using Hyperaccumulator Plants for Post Mining Rehabilitation

    Doctor Philosophy — Associate Advisor

    Other advisors:

Completed Supervision

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ResearcherID: D-1983-2013

ORCID: 0000-0002-8941-1249

Scopus ID: 6604071121

Google Scholar ID: cx_6sXsAAAAJ

Personal Profile: Link

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