Phosphate-Related Artifacts In Carbonate Mineralization Experiments

Gallagher, Kimberley L.; Braissant, Olivier; Kading, Tristan; Dupraz, Christophe; Visscher, Pieter T.

doi:10.2110/jsr.2013.9

Cited by 29 publications

(15 citation statements)

References 59 publications

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“…6H 2 O) have been reported from sediments rich in organic remains (Sánchez-Román et al 2007. In laboratory experiments, Gallagher et al (2013) have demonstrated the precipitation of struvite in association with EPS, but using strong concentrations of phosphate as a buffer (P.T. Visscher, pers.…”

Section: Crinkly Laminitesmentioning

confidence: 99%

“…2013). Gallagher et al (2013) have also indicated that the high levels of phosphate (5.8-0.1 mM) used in the batch cultures can affect not only carbonate mineral morphologies, but also can lead to the precipitation of other mineral products such as apatite or struvite. Natural environments contain 3-6 orders of magnitude less phosphate than their experimental conditions, and they observed that low phosphate levels were characterized by typical trigonal (calcite) and orthorhombic (aragonite) crystal habits (Gallagher et al 2013, p. 41).…”

Section: Crinkly Laminitesmentioning

confidence: 99%

See 1 more Smart Citation

Microbial communities and their primary to early diagenetic mineral phases; the record from Neoproterozoic microbialites of Qarn Alam, Oman

Mettraux

Homewood

Anjos

et al. 2015

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The 10 m-scale shallowing-up Neoproterozoic carbonate cycles at Qarn Alam (Oman) provide a record of microbial textures and the communities responsible for them. This is documented for four major microbialite facies. Despite their age, these microbialites show extremely fine preservation of microbial fossils and mineral associations (primary calcite and dolomite with minor phosphate, glauconite, palygorskite, hematite and goethite) and they are the record of a suite of microbial communities, from pellicular biofilms (planar laminites) to mats and gels (crinkly laminites, and stromatolitic layered and massive thrombolites) and a more complex microbial community in bushy thrombolites possibly involving a sponge-like form. Mineralized extra-cellular polymeric substances (EPS) resembles that of modern microbial mats. The mineral associations, as well as cathodoluminescence attributes, indicate oxic to suboxic conditions during deposition and early diagenesis for planar laminites and crinkly laminites, but more evaporitic to saline conditions during development of thrombolites of the upper part of a cycle. Early cementation under variable redox conditions sealed the organomineralized phases.

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Section: Crinkly Laminitesmentioning

confidence: 99%

Section: Crinkly Laminitesmentioning

confidence: 99%

Microbial communities and their primary to early diagenetic mineral phases; the record from Neoproterozoic microbialites of Qarn Alam, Oman

Mettraux

Homewood

Anjos

et al. 2015

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“…In microbialite forming mats the role of anaerobic respiration, specifically sulfate reduction, in promoting carbonate precipitation through remineralization has been well documented (Visscher et al 1998Paerl et al 2001;Baumgartner et al 2006;Nitti et al 2012;Gallagher et al 2013). Amplicon libraries of the 16S rRNA gene amplicon studies have previously shown the presence of several sulfate-reducing bacteria (SRB) mostly associated with the Desulfovibrionales in the thrombolitic mats (Mobberley et al 2012;Myshrall et al 2010).…”

Section: Energy Metabolisms That Influence Carbonate Precipitation Inmentioning

confidence: 99%

Metabolic potential of lithifying cyanobacteria-dominated thrombolitic mats

2013

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Thrombolites are unlaminated carbonate deposits formed by the metabolic activities of microbial mats and can serve as potential models for understanding the molecular mechanisms underlying the formation of lithifying communities. To assess the metabolic complexity of these ecosystems, high throughput DNA sequencing of a thrombolitic mat metagenome was coupled with phenotypic microarray analysis. Functional protein analysis of the thrombolite community metagenome delineated several of the major metabolic pathways that influence carbonate mineralization including cyanobacterial photosynthesis, sulfate reduction, sulfide oxidation, and aerobic heterotrophy. Spatial profiling of metabolite utilization within the thrombolite-forming microbial mats suggested that the top 5 mm contained a more metabolically diverse and active community than the deeper within the mat. This study provides evidence that despite the lack of mineral layering within the clotted thrombolite structure there is a vertical gradient of metabolic activity within the thrombolitic mat community. This metagenomic profiling also serves as a foundation for examining the active role individual functional groups of microbes play in coordinating metabolisms that lead to mineralization.

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“…It is stressed that spherical microstructures can also form as self‐organizing structures (SOS) by purely physicochemical processes (e.g., gas bubbles, spheroidal crystallites; Brasier et al., ; Cosmidis, Benzerara, Gheerbrant, et al., ) and by microbial mediation (e.g., smooth but variably pitted spheroidal crystallites; Gallagher, Brassiant, Kading, Dupraz, & Visscher, ) and thus to represent “pseudofossils.” While it is difficult to conclusively counter an SOS explanation, the GRF globular clusters lack collapsed, wrinkled, or exploded forms, unlike hollow hydroxyapatite spheres formed around gas bubbles (Cosmidis, Benzerara, Gheerbrant, et al., ). Morphological variation is less in natural populations than in comparable abiological structures (Brasier et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…Morphological variation is less in natural populations than in comparable abiological structures (Brasier et al, 2006). The GRF spheroids have a much more restricted size distribution than, for instance, those that nucleate in association with bacteria in batch-culture studies (Gallagher et al, 2013). Solid spheres also have been manufactured only with a simple texture of needle-like or plate-like apatite crystallites that are elongated from the centre toward the exterior of the spheres (Cosmidis, Benzerara, Gheerbrant, et al, 2013).…”

Section: Biologic Morphologymentioning

confidence: 99%

Phosphatized tungsten‐metabolizing coccoid microbes interpreted from oil shale of an Eocene lake, Green River Formation, Utah, USA

2018

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Microscopic globular structures have been observed in some beds of oil shale from eastern Utah. These beds comprise carbonate-dominated mud that is interlaminated with variably thick and continuous organic-rich layers. Collectively they are enriched in phosphorus, REEs, and actinides. The beds are considered of lacustrine origin and assigned to the Eocene Green River Formation. The globules themselves are of microcrystalline carbonate fluorapatite (μCFA), often contain concentric internal structures, and usually group together in clusters of up to 80, possibly more. Detailed SEM and microprobe analyses have revealed tungsten (W) to be almost exclusively associated with the globular clusters found within the more organic-rich laminae, often at concentrations of over 200 ppm, two orders of magnitude above shale standards. The globular structures are present in freshly cut sections where they occasionally grade into a μCFA matrix cement. This, together with the draping of the clusters by stringers of organic matter that would have accumulated in the Eocene lake, confirms that the structures are not a contaminant. The limited range of sizes and globular shapes is consistent with the morphology of coccoidal bacteria: Concentric internal structures may represent remnants of the nucleoid and cell wall. Paired concentric structures may indicate cell division (reproduction) processes were occurring until mineralization. The phosphate mineralization itself may have been promoted by release of phosphate from the stressed cells, bringing porewaters to supersaturation, or by the cells acting as nucleation sites. The recording of trace amounts of W almost exclusively in globular clusters preserved in the most organic-rich stringers (anoxia prone) further suggests facultative use of W-enzymes in a microbial metabolism. Combined, their context, morphology, and indication of biogenic process are strong evidence that the structures are fossilized (phosphatized) microbes, possibly sulfate-reducing bacteria, or methanogenic archaea.

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Phosphate-Related Artifacts In Carbonate Mineralization Experiments

Cited by 29 publications

References 59 publications

Microbial communities and their primary to early diagenetic mineral phases; the record from Neoproterozoic microbialites of Qarn Alam, Oman

Microbial communities and their primary to early diagenetic mineral phases; the record from Neoproterozoic microbialites of Qarn Alam, Oman

Metabolic potential of lithifying cyanobacteria-dominated thrombolitic mats

Phosphatized tungsten‐metabolizing coccoid microbes interpreted from oil shale of an Eocene lake, Green River Formation, Utah, USA

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