Multiscale characterization of pyritized plant tissues in blueschist facies metamorphic rocks

Bernard, Sylvain; Benzerara, Karim; Beyssac, Olivier; Brown, Gordon E.

doi:10.1016/j.gca.2010.06.011

Cited by 57 publications

(36 citation statements)

References 109 publications

(166 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 7a is displayed in Figure 8. This spectrum exhibits a lower Fe(II)/Fe(III) ratio than pure magnetite (Fe 3 O 4 ), and does not match published spectra of maghemite (g-Fe 2 O 3 ), the oxidation product of magnetite (Bernard et al, 2010). In aggregate-free regions, a small, Fe(II)-rich background level was consistently detected.…”

Section: Identification Of Bacteriacontrasting

confidence: 60%

Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth

et al. 2012

View full text Add to dashboard Cite

Iron-reducing bacteria (FeRB) play key roles in anaerobic metal and carbon cycling and carry out biogeochemical transformations that can be harnessed for environmental bioremediation. A subset of FeRB require direct contact with Fe(III)-bearing minerals for dissimilatory growth, yet these bacteria must move between mineral particles. Furthermore, they proliferate in planktonic consortia during biostimulation experiments. Thus, a key question is how such organisms can sustain growth under these conditions. Here we characterized planktonic microbial communities sampled from an aquifer in Rifle, Colorado, USA, close to the peak of iron reduction following in situ acetate amendment. Samples were cryo-plunged on site and subsequently examined using correlated two- and three-dimensional cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission X-ray microscopy (STXM). The outer membranes of most cells were decorated with aggregates up to 150 nm in diameter composed of ∼3 nm wide amorphous, Fe-rich nanoparticles. Fluorescent in situ hybridization of lineage-specific probes applied to rRNA of cells subsequently imaged via cryo-TEM identified Geobacter spp., a well-studied group of FeRB. STXM results at the Fe L2,3 absorption edges indicate that nanoparticle aggregates contain a variable mixture of Fe(II)–Fe(III), and are generally enriched in Fe(III). Geobacter bemidjiensis cultivated anaerobically in the laboratory on acetate and hydrous ferric oxyhydroxides also accumulated mixed-valence nanoparticle aggregates. In field-collected samples, FeRB with a wide variety of morphologies were associated with nano-aggregates, indicating that cell surface Fe(III) accumulation may be a general mechanism by which FeRB can grow while in planktonic suspension.

show abstract

Section: Identification Of Bacteriacontrasting

confidence: 60%

Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Recently, the analytical improvements of microspectroscopy techniques in general and synchrotron-based techniques in particular (see Templeton and Knowles 2009 for a review) have allowed the chemical and structural characterization of metamorphic organic matter down to the nanometer scale. Altogether, these studies have shown that even high-grade metamorphic rocks may retain morphologically and geochemically recognizable traces of life, depending notably on the original biochemical nature of the ▶ biopolymer (Bernard et al 2007(Bernard et al , 2010.…”

Section: Overviewmentioning

confidence: 97%

“…However, fossilized biosignatures are not immutable but prone to degradation during diagenesis and ▶ metamorphism and may become difficult to distinguish from signatures of abiogenic compounds (e.g., García-Ruiz et al 2003;Pasteris and Wopenka 2003;McCollom and Seewald 2006). Nevertheless, from the multiscale characterization of organic-rich ▶ metamorphic rocks using advanced synchrotron-based micro ▶ spectroscopy techniques, Bernard et al (2007Bernard et al ( , 2010 have shown that high-grade metamorphism might not totally erase structural and chemical bio-features, at least at the sub-micrometer scale.…”

Section: Definitionmentioning

confidence: 99%

Background

Rouan¹

2015

Encyclopedia of Astrobiology

View full text Add to dashboard Cite

“…Specific crystallographic orientation (perpendicular to cell walls) of crystalline phases precipitated within bacterial periplasm [61,86,87], at the cell surface or in association with cyanobacterial sheaths [32] may also promote the preservation of specific biosignatures upon fossilization and diagenetic processes. Last, trapping of organics within minerals upon diagenesis and even metamorphism has been shown to allow, to some extent, the preservation of geochemical biosignatures [14,24,25,29,88].…”

Section: Fossilization Of Calcifying Bacterial Coloniesmentioning

confidence: 99%

“…As a result, the general paleobiological perception has long been that burial and diagenetic processes are detrimental to the preservation of biosignatures. Yet, metamorphic rocks may retain, to some extent, morphologically and geochemically recognizable traces of life [14,[22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Calcification and Diagenesis of Bacterial Colonies

et al. 2015

Self Cite

View full text Add to dashboard Cite

Evidencing ancient interspecific associations in the fossil record may be challenging, particularly when bacterial organisms have most likely been degraded during diagenesis. Yet, documenting ancient interspecific associations may provide valuable insights into paleoenvironmental conditions and paleocommunities. Here, we report the multiscale characterization of contemporary and fossilized calcifying bacterial colonies found on contemporary shrimps from Mexico (La Paz Bay) and on 160-Ma old fossilized decapods (shrimps) from the Lagerstätte of La Voulte-sur-Rhône (France), respectively. We document the fine scale morphology, the inorganic composition and the organic signatures of both the contemporary and fossilized structures formed by these bacterial colonies using a combination of electron microscopies and synchrotron-based scanning transmission X-ray microscopy. In addition to discussing the mechanisms of carbonate precipitation by such bacterial colonies, the present study illustrates the degradation of bacterial remains occurring during diagenesis.

show abstract

Multiscale characterization of pyritized plant tissues in blueschist facies metamorphic rocks

Cited by 57 publications

References 109 publications

Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth

Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth

Background

Calcification and Diagenesis of Bacterial Colonies

Contact Info

Product

Resources

About