Microbial Reducibility of Fe(III) Phases Associated with the Genesis of Iron Ore Caves in the Iron Quadrangle, Minas Gerais, Brazil

Parker, Ceth W.; Wolf, Julie A.; Auler, Augusto S.; Barton, Hazel A.; Senko, John M.

doi:10.3390/min3040395

Cited by 43 publications

(36 citation statements)

References 50 publications

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“…Indeed, in such an oligotrophic environment, bacterial communities are expected to take advantage of element diffusion from the orthoquartzite, which concurrently involves not only silica but also other minor rock components 13 , such as iron, zinc, barium and calcium which are necessary for the microbial metabolism/growth. Similar processes of metal mobilization from the host rock have been described also in hypogenic caves in limestone 32 , 33 and in peculiar iron-silica caves in Brazil 34 . In these cases the microbial community is proposed to bio-weather the rock substrate for accessing reduced metals (mainly manganese and iron) that are oxidized by microbial activities and deposited at the rock-air interface (i.e.…”

Section: Discussionsupporting

confidence: 72%

Microbial diversity and biosignatures of amorphous silica deposits in orthoquartzite caves

Sauro

Cappelletti

Ghezzi

et al. 2018

Sci Rep

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Chemical mobility of crystalline and amorphous SiO2 plays a fundamental role in several geochemical and biological processes, with silicate minerals being the most abundant components of the Earth’s crust. Although the oldest evidences of life on Earth are fossilized in microcrystalline silica deposits, little is known about the functional role that bacteria can exert on silica mobility at non-thermal and neutral pH conditions. Here, a microbial influence on silica mobilization event occurring in the Earth’s largest orthoquartzite cave is described. Transition from the pristine orthoquartzite to amorphous silica opaline precipitates in the form of stromatolite-like structures is documented through mineralogical, microscopic and geochemical analyses showing an increase of metals and other bioessential elements accompanied by permineralized bacterial cells and ultrastructures. Illumina sequencing of the 16S rRNA gene describes the bacterial diversity characterizing the consecutive amorphization steps to provide clues on the biogeochemical factors playing a role in the silica solubilization and precipitation processes. These results show that both quartz weathering and silica mobility are affected by chemotrophic bacterial communities, providing insights for the understanding of the silica cycle in the subsurface.

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Section: Discussionsupporting

confidence: 72%

Microbial diversity and biosignatures of amorphous silica deposits in orthoquartzite caves

Sauro

Cappelletti

Ghezzi

et al. 2018

Sci Rep

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“…A detailed geochronological, petrographic and geochemical study conducted by Monteiro et al (2014) indicated that biological processes were likely to be the major mechanism driving the reductive dissolution of iron oxides in canga. Parker et al (2013) also supported the hypothesis that microbial reductive dissolution of Fe(III) oxides is critical to the transport and cycling of iron in canga. Conversely, processes responsible for the precipitation of several goethite generations and textures in iron systems (Ramanaidou, 2009)…”

Section: Introductionsupporting

confidence: 69%

“…Iron reduction was not directly investigated in this study but is hypothesised to be driven by biological mechanisms and a limiting step in the cycling of iron associated with canga formation (Monteiro et al, 2014). Parker et al (2013) demonstrated that the poorly crystalline Fe(III) oxides in canga were more susceptible to bioreduction by Shewanella oneidensis MR-1 than crystalline phases (hematite), supporting the hypothesis that bacteria may play a role in canga genesis.…”

Section: Significance Of Microbial Fossils In Cangamentioning

confidence: 64%

Evidence of biogeochemical processes in iron duricrust formation

Levett

Gagen

Shuster

et al. 2016

Journal of South American Earth Sciences

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Canga is a moderately hard iron-rich duricrust primarily composed of goethite as a result of the weathering of banded iron formations. Canga duricrusts lack a well-developed soil profile and consequently form an innate association with rupestrian plants that may become ferruginised, contributing to canga possessing macroscopic biological features. Examination of polished canga using a field emission scanning electron microscope (FE-SEM) revealed the biological textures associated with canga extended to the sub-millimetre scale in petrographic sections and polished blocks. Laminae that formed by abiotic processes and regions where goethite cements were formed in association with microorganisms were observed in canga. Biological cycling of iron within canga has resulted in two distinct forms of microbial fossilisation: permineralisation of multispecies biofilms and mineralisation of cell envelopes. Goethite permineralised biofilms frequently formed around goethite-rich kaolinite grains in close proximity to goethite bands and were composed of micrometre-scale rod-shaped, cocci and filamentous microfossils. In contrast, the cell envelopes immobilised by authigenic iron oxides were primarily of rod-shaped microorganisms, were not permineralised and occurred in pore spaces within canga. Complete mineralisation of intact rod-shaped casts and the absence of permineralisation suggested mineralised cell envelopes may represent fossilised iron-oxidising bacteria in the canga ecosystem. Replication of these iron-oxidising bacteria appeared to infill the porous regions within canga. Synchrotron-based Fourier transform infrared (FTIR) microspectroscopy demonstrated that organic biomarkers were poorly preserved with only weak bands indicative of aliphatic methylene (CH 2) associated with permineralised microbial biofilms. High resolution imaging of microbial fossils in canga that had been etched with oxalic acid supported the poor preservation of organic biomarkers within canga, indicating mineralogical replacement of organic biomarkers.

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“…High variations in heterotrophic prokaryotic abundance were observed in karst aquifers and higher cell abundance and biomass were discovered during summer (Wilhartitz et al 2009), which indicated a potential relationship between microbial community and temperature. Moreover microbes are observed to be capable of mediating various biogeochemical processes in karst systems from overlying soil to the inside of the cave (Barton and Jurado 2007;Engel et al 2013) via multiple ways and influence the formation of minerals in cave systems (Barton and Northup 2007;Parker et al 2013;Wang et al 2010). However, the microbial communities in dripping water are far less investigated (Laiz et al 1999;Liu et al 2010) particularly on their seasonal variation on a long time scale and the relationship with environmental changes.…”

mentioning

confidence: 97%

Five-Year Monitoring of Bacterial Communities in Dripping Water from the Heshang Cave in Central China: Implication for Paleoclimate Reconstruction and Ecological Functions

Yun

Xiao

Wang

et al. 2016

Geomicrobiology Journal

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Microbial lipids in stalagmites are increasingly used to reconstruct the paleoclimate change, necessitating the investigations on microbial communities in dripping waters. A pilot molecular survey was conducted on bacterial communities of dripping waters at two sites (1D and 3D) in Heshang Cave of Hubei province in central China for a period of 2008 to 2013. The samples were subjected to genome DNA extraction, 16S rRNA gene amplification, clone library construction and phylogenetic analysis to explore the seasonal variation of bacterial communities and their association with environmental factors including regional air temperature， precipitation, cave temperature, pH, conductivity and dripping rate of the water samples. Seasonal variations were clearly observed in components and diversities of bacterial communities at both sites. Bacterial community was dominated by Gammaproteobacteria in autumn and winter, whereasDownloaded by [FU Berlin] at 04:42 04 July 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2Betaproteobacteria became dominant in samples collected in summer and spring. Among the environmental factors investigated, regional air temperature was found to have a strong impact on bacterial communities indicated by cluster and redundancy analysis. Moreover the bacterial biodiversity was observed to increase with the temperature rising. Bacteria identified in dripping water were either oligotrophs or able to acquire nutrients from minerals under oligotrophic conditions. They may also be able to induce calcite precipitation in cave systems. Our data shed light on the potential of microbes used as a tool for the reconstruction of paleo-temperature as well as on the ecological functions of bacterial communities in oligotrophic caves.

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Microbial Reducibility of Fe(III) Phases Associated with the Genesis of Iron Ore Caves in the Iron Quadrangle, Minas Gerais, Brazil

Cited by 43 publications

References 50 publications

Microbial diversity and biosignatures of amorphous silica deposits in orthoquartzite caves

Microbial diversity and biosignatures of amorphous silica deposits in orthoquartzite caves

Evidence of biogeochemical processes in iron duricrust formation

Five-Year Monitoring of Bacterial Communities in Dripping Water from the Heshang Cave in Central China: Implication for Paleoclimate Reconstruction and Ecological Functions

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