scholarly journals Effects of Fe(III) Oxide Mineralogy and Phosphate on Fe(II) Secondary Mineral Formation during Microbial Iron Reduction

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 149
Author(s):  
Edward J. O’Loughlin ◽  
Maxim I. Boyanov ◽  
Christopher A. Gorski ◽  
Michelle M. Scherer ◽  
Kenneth M. Kemner

The bioreduction of Fe(III) oxides by dissimilatory iron-reducing bacteria may result in the formation of a suite of Fe(II)-bearing secondary minerals, including magnetite (a mixed Fe(II)/Fe(III) oxide), siderite (Fe(II) carbonate), vivianite (Fe(II) phosphate), chukanovite (ferrous hydroxy carbonate), and green rusts (mixed Fe(II)/Fe(III) hydroxides). In an effort to better understand the factors controlling the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of Fe(III) oxide mineralogy, phosphate concentration, and the availability of an electron shuttle (9,10-anthraquinone-2,6-disulfonate, AQDS) on the bioreduction of a series of Fe(III) oxides (akaganeite, feroxyhyte, ferric green rust, ferrihydrite, goethite, hematite, and lepidocrocite) by Shewanella putrefaciens CN32, and the resulting formation of secondary minerals, as determined by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. The overall extent of Fe(II) production was highly dependent on the type of Fe(III) oxide provided. With the exception of hematite, AQDS enhanced the rate of Fe(II) production; however, the presence of AQDS did not always lead to an increase in the overall extent of Fe(II) production and did not affect the types of Fe(II)-bearing secondary minerals that formed. The effects of the presence of phosphate on the rate and extent of Fe(II) production were variable among the Fe(III) oxides, but in general, the highest loadings of phosphate resulted in decreased rates of Fe(II) production, but ultimately higher levels of Fe(II) than in the absence of phosphate. In addition, phosphate concentration had a pronounced effect on the types of secondary minerals that formed; magnetite and chukanovite formed at phosphate concentrations of ≤1 mM (ferrihydrite), <~100 µM (lepidocrocite), 500 µM (feroxyhyte and ferric green rust), while green rust, or green rust and vivianite, formed at phosphate concentrations of 10 mM (ferrihydrite), ≥100 µM (lepidocrocite), and 5 mM (feroxyhyte and ferric green rust). These results further demonstrate that the bioreduction of Fe(III) oxides, and accompanying Fe(II)-bearing secondary mineral formation, is controlled by a complex interplay of mineralogical, geochemical, and microbiological factors.

2001 ◽  
Vol 7 (S2) ◽  
pp. 756-757
Author(s):  
Alice C. Dohnalkova ◽  
Yuri A. Gorby ◽  
Jeff McLean ◽  
Jim K. Fredrickson ◽  
David W. Kennedy

Dissimilatory iron reducing bacteria have been extensively studied for their ability to reduce ferric iron Fe(III) to ferrous iron Fe(II), as well as several multivalent heavy metals and radionuclides as a mode of energy-yielding respiration. Shewanella putrefaciens strain CN32 was used to investigate the mechanism of biogenic metal reduction in systems simulating conditions of natural anaerobic iron reducing environments in the subsurface contaminated with U and Tc as a possible strategy for bioremediation of soils containing these contaminants. As previously reviewed, U(VI) is soluble in most groundwaters, while U(VI) generally precipitates as the insoluble mineral uraninite. Formation of bioreduced minerals can lead to immobilization of these contaminants in the subsurface, which might be a very useful strategy for in situ bioremediation.To determine the metal reduction and the formation of biogenic Fe(II), U(IV) and Tc(IV) minerals, experiments with CN32 exposed to well-defined aqueous solutions were conducted. Metal reduction was measured with time, and the resulting solids were analyzed by X-ray diffraction, scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDS).


1989 ◽  
Vol 53 (369) ◽  
pp. 125-129 ◽  
Author(s):  
A. Livingstone

A Working quarry, at Loanhead (NS363557) within the Clyde Plateau Carboniferous lavas, is traversed by a tholeiitic Tertiary dyke some 25-30 m wide. Throughout the quarry the lavas are extensively altered and the most prominent secondary minerals are calcite and prehnite. Adjacent to the dyke is an indefinite alteration zone within which garnet has developed in close association with analcime and thomsonite. Contact metamorphism is not apparent. Secondary minerals in the quarried lavas and from the alteration zone have been described by Meikle (1989). The most salient feature of secondary mineral formation central to this paper is that grossular and andradite occur, in situ, in close proximity to the dyke, and only in the amygdales.


Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 434 ◽  
Author(s):  
Edward J. O’Loughlin ◽  
Christopher A. Gorski ◽  
Theodore M. Flynn ◽  
Michelle M. Scherer

The bioreduction of Fe(III) oxides by dissimilatory iron reducing bacteria (DIRB) may result in the production of a suite of Fe(II)-bearing secondary minerals, including magnetite, siderite, vivianite, green rusts, and chukanovite; the formation of specific phases controlled by the interaction of various physiological and geochemical factors. In an effort to better understand the effects of individual electron donors on the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of a series of potential electron donors on the bioreduction of lepidocrocite (γ-FeOOH) by Shewanella putrefaciens CN32. Biomineralization products were identified by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. Acetate, citrate, ethanol, glucose, glutamate, glycerol, malate, and succinate were not effectively utilized for the bioreduction of lepidocrocite by S. putrefaciens CN32; however, substantial Fe(II) production was observed when formate, lactate, H2, pyruvate, serine, or N acetylglucosamine (NAG) was provided as an electron donor. Carbonate or sulfate green rust was the dominant Fe(II)-bearing secondary mineral when formate, H2, lactate, or NAG was provided, however, siderite formed with pyruvate or serine. Geochemical modeling indicated that pH and carbonate concentration are the key factors determining the prevalence of carbonate green rust verses siderite.


2021 ◽  
pp. 26-42
Author(s):  
N. ZINCHUK

Methods of studying postmagmatic and hypergene kimberlite rock alteration, as well as identifying secondary minerals and their associations are characterized. It is shown that secondary mineral formation processes took place in a wide temperature range and they are caused by their downward change of medium reaction from alkaline to acidic followed by neutralization, which resulted in dissolution, additional growth and emergence of new secondary mineral generations.


2017 ◽  
Vol 13 (2) ◽  
pp. 149-170 ◽  
Author(s):  
Rosanna Greenop ◽  
Mathis P. Hain ◽  
Sindia M. Sosdian ◽  
Kevin I. C. Oliver ◽  
Philip Goodwin ◽  
...  

Abstract. The boron isotope composition (δ11B) of foraminiferal calcite reflects the pH and the boron isotope composition of the seawater the foraminifer grew in. For pH reconstructions, the δ11B of seawater must therefore be known, but information on this parameter is limited. Here we reconstruct Neogene seawater δ11B based on the δ11B difference between paired measurements of planktic and benthic foraminifera and an estimate of the coeval water column pH gradient from their δ13C values. Carbon cycle model simulations underscore that the ΔpH–Δδ13C relationship is relatively insensitive to ocean and carbon cycle changes, validating our approach. Our reconstructions suggest that δ11Bsw was  ∼  37.5 ‰ during the early and middle Miocene (roughly 23–12 Ma) and rapidly increased during the late Miocene (between 12 and 5 Ma) towards the modern value of 39.61 ‰. Strikingly, this pattern is similar to the evolution of the seawater isotope composition of Mg, Li and Ca, suggesting a common forcing mechanism. Based on the observed direction of change, we hypothesize that an increase in secondary mineral formation during continental weathering affected the isotope composition of riverine input to the ocean since 14 Ma.


Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 413 ◽  
Author(s):  
Fan Xu ◽  
Xuelian You ◽  
Qing Li ◽  
Yi Liu

Microbes can mediate the precipitation of primary dolomite under surface conditions. Meanwhile, primary dolomite mediated by microbes often contains more Fe2+ than standard dolomite in modern microbial culture experiments. Ferroan dolomite and ankerite have been regarded as secondary products. This paper reviews the process and possible mechanisms of microbial mediated precipitation of primary ferroan dolomite and/or ankerite. In the microbial geochemical Fe cycle, many dissimilatory iron-reducing bacteria (DIRB), sulfate-reducing bacteria (SRB), and methanogens can reduce Fe3+ to Fe2+, while SRB and methanogens can also promote the precipitation of primary dolomite. There are an oxygen respiration zone (ORZ), an iron reduction zone (IRZ), a sulfate reduction zone (SRZ), and a methanogenesis zone (MZ) from top to bottom in the muddy sediment diagenesis zone. DIRB in IRZ provide the lower section with Fe2+, which composes many enzymes and proteins to participate in metabolic processes of SRB and methanogens. Lastly, heterogeneous nucleation of ferroan dolomite on extracellular polymeric substances (EPS) and cell surfaces is mediated by SRB and methanogens. Exploring the origin of microbial ferroan dolomite may help to solve the “dolomite problem”.


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