The role of aluminium in the preservation of microbial biosignatures

Levett, Alan; Gagen, Emma J.; Diao, Hui; Guagliardo, Paul; Rintoul, Llew; Paz, Anat; Vasconcelos, Paulo M.; Southam, Gordon

doi:10.1016/j.gsf.2018.06.006

Cited by 18 publications

(15 citation statements)

References 39 publications

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“…Here, we present abundant mineralised cell envelope structures fossilised within a goethite-rich vein structure that cross-cuts a weathering BIF 6 . These indisputable microbial fossils provide a superb opportunity to understand potential mineralogical biosignatures preserved during microbial fossilisation by authigenic minerals.…”

Section: Discussionmentioning

confidence: 99%

“…Given the low-temperature formation and alteration of the iron oxide minerals 9 , the aliphatic hydrocarbon moieties preserved with the microfossils are likely to be replaced during low-temperature metasomatism by iron and aluminium in solution. Levett et al 6 demonstrated that organic biosignatures associated with younger (ca. 2 Ma) permineralised microfossils in the overlying duricrust are completely replaced, likely due to the increased cycling of iron oxide minerals that occurs near the surface 16 .…”

Section: Discussionmentioning

confidence: 99%

“…Naturally fossilised microorganisms were identified within a goethite-rich vein that cross-cut an iron ore deposit in the Quadrilátero Ferrífero, Minas Gerais, Brazil from a depth of approximately 15 m 6,7 . The goethite-rich vein formed during the weathering of the hosting BIF and the vein minerals, likely to be carbonate or sulphide 7 .…”

Section: Methodsmentioning

confidence: 99%

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Characterisation of iron oxide encrusted microbial fossils

Levett

Gagen

Rintoul

et al. 2020

Sci Rep

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Robust methods for the characterisation of microbial biosignatures in geological matrices is critical for developing mineralogical biosignatures. Studying microbial fossils is fundamental for our understanding of the role microorganisms have played in elemental cycling in modern and ancient environments on Earth and potentially Mars. Here, we aim to understand what promotes the fossilisation of microorganisms after the initial stages of biomineralisation, committing bacteriomorphic structures to the geological record within iron-rich environments. Mineral encrusted cell envelope structures were routinely identified within a goethite-rich vein that cross-cut the saprolite (iron ore) of a weathered banded iron formation (BIF) system in the Quadrilátero Ferrífero, Brazil. The preservation of potential organic and mineralogical biosignatures associated with these fossils was characterised using the following high-resolution analytical techniques: scanning and transmission electron microscopy, focused ion beam scanning electron microscopy, nanoscale secondary ion mass spectrometry, synchrotron-based Fourier transform infrared spectroscopy and Raman spectroscopy. Electron microscopy demonstrated that mineral nucleation associated with a range of cell envelope structures typically followed the extant cell templates. These biologically-influenced iron-rich minerals are microcrystalline with minimal secondary growth. In contrast, intracellular mineralisation formed larger minerals that grew inward from the cell membrane to infill intracellular voids after cell death. A three dimensional reconstruction of encrusted cell envelopes in a fossilised biofilm suggests that microorganisms may be able to replicate, during the initial stages of mineralisation. Carbon and nitrogen signatures are preserved associated with the cell envelope structures; however, there were no conclusive mineralogical biosignatures associated with the mineralised cell envelopes highlighting the classical importance of morphology and elemental biosignatures in determining the biogenicity of bacteriomorphic structures.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Characterisation of iron oxide encrusted microbial fossils

Levett

Gagen

Rintoul

et al. 2020

Sci Rep

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“…Note that cells mineralized in pseudoacicular minerals were observed in both the lower and middle region (compare Figure 7c with Figure 8b inset). The study by Levett et al [51] suggested that aluminum could have an important role in the preservation of cellular structures within iron duricrusts-i.e., canga. The acidic conditions of this environment would intuitively support the solubilization of aluminum and could also have an important role in the preservation of larger cellular structures within the schwertmannite/goethite laminations (Figure 8c).…”

Section: Interpreting Biogeochemical Processes Contributing To Tif Dementioning

confidence: 99%

Terraced Iron Formations: Biogeochemical Processes Contributing to Microbial Biomineralization and Microfossil Preservation

et al. 2018

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Terraced iron formations (TIFs) are laminated structures that cover square meter-size areas on the surface of weathered bench faces and tailings piles at the Mount Morgan mine, which is a non-operational open pit mine located in Queensland, Australia. Sampled TIFs were analyzed using molecular and microanalytical techniques to assess the bacterial communities that likely contributed to the development of these structures. The bacterial community from the TIFs was more diverse compared to the tailings on which the TIFs had formed. The detection of both chemolithotrophic iron-oxidizing bacteria, i.e., Acidithiobacillus ferrooxidans and Mariprofundus ferrooxydans, and iron-reducing bacteria, i.e., Acidobacterium capsulatum, suggests that iron oxidation/reduction are continuous processes occurring within the TIFs. Acidophilic, iron-oxidizing bacteria were enriched from the TIFs. High-resolution electron microscopy was used to characterize iron biomineralization, i.e., the association of cells with iron oxyhydroxide mineral precipitates, which served as an analog for identifying the structural microfossils of individual cells as well as biofilms within iron oxyhydroxide laminations—i.e., alternating layers containing schwertmannite (Fe16O16(OH)12(SO4)2) and goethite (FeO(OH)). Kinetic modeling estimated that it would take between 0.25–2.28 years to form approximately one gram of schwertmannite as a lamination over a one-m2 surface, thereby contributing to TIF development. This length of time could correspond with seasonable rainfall or greater than average annual rainfall. In either case, the presence of water is critical for sustaining microbial activity, and subsequently iron oxyhydroxide mineral precipitation. The TIFs from the Mount Morgan mine also contain laminations of gypsum (CaSO·2H2O) alternating with iron oxyhydroxide laminations. These gypsum laminations likely represented drier periods of the year, in which millimeter-size gypsum crystals presumably precipitated as water gradually evaporated. Interestingly, gypsum acted as a substrate for the attachment of cells and the growth of biofilms that eventually became mineralized within schwertmannite and goethite. The dissolution and reprecipitation of gypsum suggest that microenvironments with circumneutral pH conditions could exist within TIFs, thereby supporting iron oxidation under circumneutral pH conditions. In conclusion, this study highlights the relationship between microbes for the development of TIFs and also provides interpretations of biogeochemical processes contributing to the preservation of bacterial cells and entire biofilms under acidic conditions.

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“…Aluminium is the third most abundant element but the most abundant metal in the earth's crust-8.1wt % [1,2]. Variety of Al applications are in the electrical and electronics, construction, transportation and chemical industries.…”

Section: Introductionmentioning

confidence: 99%

Effect of ion exchange dialysis process variables on aluminium permeation using response surface methodology

Asante-Sackey

Rathilal

Pillay

et al. 2019

Environmental Engineering Research

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This study investigated aluminum permeation using a counter flow ion exchange dialysis (IED) system. The optimum conditions for permeation were investigated using response surface methodology (RSM). Effect of four factors- feed concentration (100-2,000 ppm, A), feed flow rate (25-85%, B), sweep concentration (0.25-1 N HCl, C) and sweep flow rate (25-85%, D) were studied using face centered central composite (FC-CCD) statistical experimental design. A RSM model was developed based on the experimental permeation data and the response plot was developed. The FC-CCD model predicted permeation correlated with the experimental data. The regression coefficient (R<sup>2</sup>) was found to be 0.9568. The experiment showed the ascending order of the effect of the variables is D < B < C < A. In a counter flow IED for Al permeation, the sweep flow rate is insignificant (p > 0.05). Experimental validation demonstrated for target permeation of 70% was 68.8% ± 2.22%. This suggested that the RSM was a suitable tool in optimizing Al-permeation.

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The role of aluminium in the preservation of microbial biosignatures

Cited by 18 publications

References 39 publications

Characterisation of iron oxide encrusted microbial fossils

Characterisation of iron oxide encrusted microbial fossils

Terraced Iron Formations: Biogeochemical Processes Contributing to Microbial Biomineralization and Microfossil Preservation

Effect of ion exchange dialysis process variables on aluminium permeation using response surface methodology

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