Physiology of phototrophic iron(II)-oxidizing bacteria: implications for modern and ancient environments

Hegler, Florian; Posth, Nicole R.; Jiang, Jie; Kappler, Andreas

doi:10.1111/j.1574-6941.2008.00592.x

Cited by 186 publications

(185 citation statements)

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“…Water samples for quantification of ferrous and ferric iron were immediately acidified with 1 M HCl. Fe(II) and total Fe (Fe tot ) were quantified spectrophotometrically by the ferrozine assay, as described previously (26). Samples for quantification of dissolved ions by ion chromatography were collected in 50-ml Falcon tubes and analyzed on a Dionex DX-120 ion chromatograph equipped with an autosampler, an AS23 anion column, and a CS 12A cation column.…”

Section: Methodsmentioning

confidence: 99%

Influence of Seasonal and Geochemical Changes on the Geomicrobiology of an Iron Carbonate Mineral Water Spring

Hegler

Lösekann-Behrens

Hanselmann

et al. 2012

Appl Environ Microbiol

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Fuschna Spring in the Swiss Alps (Engadin region) is a bicarbonate iron(II)-rich, pH-neutral mineral water spring that is dominated visually by dark green microbial mats at the side of the flow channel and orange iron(III) (oxyhydr)oxides in the flow channel. Gradients of O 2 , dissolved iron(II), and bicarbonate establish in the water. Our goals were to identify the dominating biogeochemical processes and to determine to which extent changing geochemical conditions along the flow path and seasonal changes influence mineral identity, crystallinity, and microbial diversity. Geochemical analysis showed microoxic water at the spring outlet which became fully oxygenated within 2.3 m downstream. X-ray diffraction and Mössbauer spectroscopy revealed calcite (CaCO 3 ) and ferrihydrite [Fe(OH) 3 ] to be the dominant minerals which increased in crystallinity with increasing distance from the spring outlet. Denaturing gradient gel electrophoresis banding pattern cluster analysis revealed that the microbial community composition shifted mainly with seasons and to a lesser extent along the flow path. 16S rRNA gene sequence analysis showed that microbial communities differ between the flow channel and the flanking microbial mat. Microbial community analysis in combination with most-probable-number analyses and quantitative PCR (qPCR) showed that the mat was dominated by cyanobacteria and the channel was dominated by microaerophilic Fe(II) oxidizers (1.97 ؋ 10 7 ؎ 4.36 ؋ 10 6 16S rRNA gene copies g ؊1 using Gallionella-specific qPCR primers), while high numbers of Fe(III) reducers (10 9 cells/g) were identified in both the mat and the flow channel. Phototrophic and nitrate-reducing Fe(II) oxidizers were present as well, although in lower numbers (10 3 to 10 4 cells/g). In summary, our data suggest that mainly seasonal changes caused microbial community shifts, while geochemical gradients along the flow path influenced mineral crystallinity.

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Section: Methodsmentioning

confidence: 99%

Influence of Seasonal and Geochemical Changes on the Geomicrobiology of an Iron Carbonate Mineral Water Spring

Hegler

Lösekann-Behrens

Hanselmann

et al. 2012

Appl Environ Microbiol

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“…Thiodictyon sp. strain f4 displays the fastest rates of iron oxidation of all phototrophic iron-oxidizing bacteria that have been isolated (Hegler et al, 2008). Interestingly, Widdel et al (1993) reported that none of the authenticated Thiodictyon spp.…”

Section: Phototrophic Iron-oxidizing Proteobacteriamentioning

confidence: 99%

The iron-oxidizing proteobacteria

2011

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The ‘iron bacteria’ are a collection of morphologically and phylogenetically heterogeneous prokaryotes. They include some of the first micro-organisms to be observed and described, and continue to be the subject of a considerable body of fundamental and applied microbiological research. While species of iron-oxidizing bacteria can be found in many different phyla, most are affiliated with the Proteobacteria. The latter can be subdivided into four main physiological groups: (i) acidophilic, aerobic iron oxidizers; (ii) neutrophilic, aerobic iron oxidizers; (iii) neutrophilic, anaerobic (nitrate-dependent) iron oxidizers; and (iv) anaerobic photosynthetic iron oxidizers. Some species (mostly acidophiles) can reduce ferric iron as well as oxidize ferrous iron, depending on prevailing environmental conditions. This review describes what is currently known about the phylogenetic and physiological diversity of the iron-oxidizing proteobacteria, their significance in the environment (on the global and micro scales), and their increasing importance in biotechnology.

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“…Soluble Fe was measured before and after sub-culturing by taking liquid samples anoxically using an N 2 flushed syringe, filtered through a 0.2 mm regenerated cellulose filter (Sartorius, G€ ottingen Germany) and transferred into 0.5 M HCl (trace metal grade, HN53.1, Carl Roth, Karlsruhe, Germany) (Sztejrenszus et al 2016). Fe 2C was measured following the ferrozine assay (Stookey 1970;Hegler et al 2008) with modifications (50% w:v ammonium acetate, 0.1% w:v ferrozine).…”

Section: Incubation Experimentsmentioning

confidence: 99%

Potentially Active Iron, Sulfur, and Sulfate Reducing Bacteria in Skagerrak and Bothnian Bay Sediments

Reyes

Schneider

Thürmer

et al. 2017

Geomicrobiology Journal

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In many marine surface sediments, the reduction of manganese (Mn) and iron (Fe) oxides is obscured by sulfate reduction, which is regarded as the predominant anaerobic microbial respiration process. However, many dissimilatory sulfate and sulfur reducing microorganisms are known to utilize alternative electron acceptors such as metal oxides. In this study, we tested whether sulfate and sulfur reducing bacteria are linked to metal oxide reduction based on biogeochemical modeling of porewater concentration profiles of Mn 2C and Fe 2C in Bothnian Bay (BB) and Skagerrak (SK) sediments. Steady-state modeling of Fe 2C and Mn 2C porewater profiles revealed zones of net Fe (0-9 cm BB; »10 and 20 cm SK) and Mn (0-5 cm BB; 2-8 cm SK) species transformations. 16S rRNA pyrosequencing analysis of the in-situ community showed that Desulfobacteraceae, Desulfuromonadaceae and Desulfobulbaceae were present in the zone of Fereduction of both sediments. Rhodobacteraceae were also detected at high relative abundance in both sediments. BB sediments appeared to harbor a greater diversity of potential Fe-reducers compared to SK. Additionally, when the upper 10 cm of sediment from the SK was incubated with lepidocrocite and acetate, Desulfuromonas was the dominant bacteria. Real-time quantitative polymerase chain reaction (qPCR) results showed decreasing dsrA gene copy numbers with depth coincided with decreased Fe-reduction activity. Our results support the idea that sulfur and sulfate reducing bacteria contribute to Fe-reduction in the upper centimeters of both sediments.

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Physiology of phototrophic iron(II)-oxidizing bacteria: implications for modern and ancient environments

Cited by 186 publications

References 50 publications

Influence of Seasonal and Geochemical Changes on the Geomicrobiology of an Iron Carbonate Mineral Water Spring

Influence of Seasonal and Geochemical Changes on the Geomicrobiology of an Iron Carbonate Mineral Water Spring

The iron-oxidizing proteobacteria

Potentially Active Iron, Sulfur, and Sulfate Reducing Bacteria in Skagerrak and Bothnian Bay Sediments

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