Can biological toxicity drive the contrasting behavior of platinum and gold in surface environments?

Brugger, Joël; Große, Cornelia; Plumridge, Colin; Kaminski, John E.; Paterson, David; Shar, Sahar Saad; Ta, Christine; Howard, Daryl L.; Jonge, Martin D. de; Ball, Andrew S.; Reith, Frank

doi:10.1016/j.chemgeo.2013.02.010

Cited by 41 publications

(27 citation statements)

References 62 publications

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“…This suggests that individual taxa were replaced at sites overlying the deposit, but that the concentration of toxic, mobile heavy metals in combination with geologically shorter exposure times was not sufficient to alter community composition at this level. At Fifield, soils have evolved continuously from in situ materials for millions of years (29), leading to soils highly enriched in mobile metals. Microbial communities at this site have been subjected to elevated metal concentrations for very long periods of time (potentially millions of years).…”

Section: Discussionmentioning

confidence: 99%

“…They are classified as Red Sodosols following the Australian soil classification scheme (28). Landscape evolution in the area commenced in the Early to Middle Devonian (29). Subsequent periods of weathering, laterization, and fluvial erosion have occurred since (29).…”

Section: Methodsmentioning

confidence: 99%

“…Landscape evolution in the area commenced in the Early to Middle Devonian (29). Subsequent periods of weathering, laterization, and fluvial erosion have occurred since (29). This has resulted in an undulating landscape with distinct erosional, colluvial, alluvial, and depositional landforms (Australian landscape classification system [30]).…”

Section: Methodsmentioning

confidence: 99%

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Geogenic Factors as Drivers of Microbial Community Diversity in Soils Overlying Polymetallic Deposits

Reith

Zammit

Pohrib

et al. 2015

Appl Environ Microbiol

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dThis study shows that the geogenic factors landform, lithology, and underlying mineral deposits (expressed by elevated metal concentrations in overlying soils) are key drivers of microbial community diversity in naturally metal-rich Australian soils with different land uses, i.e., agriculture versus natural bushland. One hundred sixty-eight soil samples were obtained from two metal-rich provinces in Australia, i.e., the Fifield Au-Pt field (New South Wales) and the Hillside Cu-Au-U rare-earth-element (REE) deposit (South Australia). Soils were analyzed using three-domain multiplex terminal-restriction-fragment-length-polymorphism (M-TRFLP) and PhyloChip microarrays. Geogenic factors were determined using field-mapping techniques and analyses of >50 geochemical parameters. At Fifield, microbial communities differed significantly with geogenic factors and equally with land use (P < 0.05). At Hillside, communities in surface soils (0.03-to 0.2-m depth) differed significantly with landform and land use (P < 0.05). Communities in deeper soils (>0.2 m) differed significantly with lithology and mineral deposit (P < 0.05). Across both sites, elevated metal contents in soils overlying mineral deposits were selective for a range of bacterial taxa, most importantly Acidobacteria, Bacilli, Betaproteobacteria, and Epsilonproteobacteria. In conclusion, long-term geogenic factors can be just as important as land use in determining soil microbial community diversity. Determining the drivers of microbial community composition in soils is challenging, because soils are complex ecosystems containing numerous ecological niches. This results in an immense diversity, with up to thousands of taxa per gram of soil (1). Land use, climate, vegetation, soil type, and anthropogenic pollution are strongly linked to soil microbial community structures, functions, and activities at many sites (2-4). In particular, agricultural practices are known to drive differences in soil microbial communities (5). Influences of geogenic factors, e.g., landform, underlying lithologies, and mineral deposits on soil microbial communities, have received little attention. However, three studies of soils from Switzerland and Nepal have shown that geological/mineralogical factors can significantly affect species assemblages and functions (6-8).A primary goal of geomicrobiological research is to link microbial communities and metal cycling in metallogenic environments and to determine how communities are structured due to metalassociated drivers (9). Microorganisms play a pivotal role in the biogeochemical cycling of many metals, particularly those essential for cell function, e.g., Co, Cu, Fe, Mg, Mn, Mo, Na, Ni, V, W, and Zn, and those oxidized or reduced in catabolic reactions to gain metabolic energy, e.g., As, Fe, Mn, Mo, Sb, Se, Sn, Te, U, and V (10). Therefore, metal-rich environments are useful model systems allowing links between microbial taxa and geochemical parameters to be identified (11).To date, mine tailing and acid mine drainage sites have been ...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Geogenic Factors as Drivers of Microbial Community Diversity in Soils Overlying Polymetallic Deposits

Reith

Zammit

Pohrib

et al. 2015

Appl Environ Microbiol

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“…Transport-related ductile deformation of placer gold is known to occur in these types of environments due to abiogenic processes [61]. This rapid transport and deposition permitted preservation of many deep cracks, pockets and angular surfaces, which normally would have been abraded away and rounded-off in a fluvial placer system.…”

Section: Red and Black Placer Biomats And Nanophase Goldmentioning

confidence: 99%

Biological and Geochemical Development of Placer Gold Deposits at Rich Hill, Arizona, USA

et al. 2018

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Placer gold from the Devils Nest deposits at Rich Hill, Arizona, USA, was studied using a range of micro-analytical and microbiological techniques to assess if differences in (paleo)-environmental conditions of three stratigraphically-adjacent placer units are recorded by the gold particles themselves. High-angle basin and range faulting at 5-17 Ma produced a shallow basin that preserved three placer units. The stratigraphically-oldest unit is thin gold-rich gravel within bedrock gravity traps, hosting elongated and flattened placer gold particles coated with manganese-, iron-, barium-(Mn-Fe-Ba) oxide crusts. These crusts host abundant nano-particulate and microcrystalline secondary gold, as well as thick biomats. Gold surfaces display unusual plumate-dendritic structures of putative secondary gold. A new micro-aerophilic Betaproteobacterium, identified as a strain of Comamonas testosteroni, was isolated from these biomats. Significantly, this "black" placer gold is the radiogenically youngest of the gold from the three placer units. The middle unit has well-rounded gold nuggets with deep chemical weathering rims, which likely recorded chemical weathering during a wetter period in Arizona's history. Biomats, nano-particulate gold and secondary gold growths were not observed here. The uppermost unit is a pulse placer deposited by debris flows during a recent drier period. Deep cracks and pits in the rough and angular gold from this unit host biomats and nano-particulate gold. During this late arid period, and continuing to the present, microbial communities established within the wet, oxygen-poor bedrock traps of the lowermost placer unit, which resulted in biological modification of placer gold chemistry, and production of Mn-Fe-Ba oxide biomats, which have coated and cemented both gold and sediments. Similarly, deep cracks and pits in gold from the uppermost unit provided a moist and sheltered micro-environment for additional gold-tolerant biological communities. In conclusion, placer gold from the Devils Nest deposits at Rich Hill, Arizona, USA, preserves a detailed record of physical, chemical and biological modifications.

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“…To assess if geomicrobial processes are likely to cause these differences, because the mobility of platinum and gold should differ little based on thermodynamic solubility alone, samples were collected in an environment where both metals occur under the same conditions [67]. Mineral-and groundwater samples were obtained from the Fifield platinum-gold field in New South Wales, Australia, where platinum and gold nuggets occur in a series of Tertiary eluvial and alluvial palaeo-placers.…”

Section: Differences In Environmental Mobility Of Gold-and Platinummentioning

confidence: 99%

Geobiological Cycling of Gold: From Fundamental Process Understanding to Exploration Solutions

et al. 2013

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Microbial communities mediating gold cycling occur on gold grains from (sub)-tropical, (semi)-arid, temperate and subarctic environments. The majority of identified species comprising these biofilms are β-Proteobacteria. Some bacteria, e.g., Cupriavidus metallidurans, Delftia acidovorans and Salmonella typhimurium, have developed biochemical responses to deal with highly toxic gold complexes. These include gold specific sensing and efflux, co-utilization of resistance mechanisms for other metals, and excretion of gold-complex-reducing siderophores that ultimately catalyze the biomineralization of nano-particulate, spheroidal and/or bacteriomorphic gold. In turn, the toxicity of gold complexes fosters the development of specialized biofilms on gold grains, and hence the cycling of gold in surface environments. This was not reported on isoferroplatinum grains under most near-surface environments, due to the lower toxicity of mobile platinum complexes. The discovery of gold-specific microbial responses can now drive the development of geobiological exploration tools, e.g., gold bioindicators and biosensors. Bioindicators employ genetic markers from soils and groundwaters to provide information about gold mineralization processes, while biosensors will allow in-field analyses of gold concentrations in complex sampling media.

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Can biological toxicity drive the contrasting behavior of platinum and gold in surface environments?

Cited by 41 publications

References 62 publications

Geogenic Factors as Drivers of Microbial Community Diversity in Soils Overlying Polymetallic Deposits

Geogenic Factors as Drivers of Microbial Community Diversity in Soils Overlying Polymetallic Deposits

Biological and Geochemical Development of Placer Gold Deposits at Rich Hill, Arizona, USA

Geobiological Cycling of Gold: From Fundamental Process Understanding to Exploration Solutions

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