Lithifying microbial mats in Lagoa Vermelha, Brazil: Modern Precambrian relics?

Vásconcelos, Crisógono; Warthmann, R.; McKenzie, Judith A.; Visscher, Pieter T.; Bittermann, Anne Greet; Lith, Yvonne van

doi:10.1016/j.sedgeo.2005.12.022

Cited by 191 publications

(160 citation statements)

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“…The comparison between the natural sample and the one that had undergone the simulated diagenesis experiment was carried out using electron microscopy (scanning electron microscopy (SEM) and transmission electron microscopy (TEM), see below) and a microelectrode. The latter was used for real-time measurement of pH in the upper 30 mm of the mat, following the methodology of Visscher et al 32 Under natural conditions, pH values in similar microbial mats fluctuate between o6.5 and 49 in a day-night cycle, with the lowest pH values observed during nighttime 33 . After experimental diagenesis in our study, the pH values were constant throughout the mat with an average value of 8.6.…”

Section: Methodsmentioning

confidence: 99%

Viruses as new agents of organomineralization in the geological record

et al. 2014

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Section: Methodsmentioning

confidence: 99%

Viruses as new agents of organomineralization in the geological record

et al. 2014

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“…One reason might be related to their capability to induce mineral precipitation, leading to the formation of lithified layers (Visscher et al, 1998;Dupraz and Visscher, 2005;Vasconcelos et al, 2006;Dupraz et al, 2009), which may protect dead bodies from advanced degradation. Li et al (2013) stressed on the pivotal role of microbially-induced authigenic mineralization in fossilization and it has been reported in many instances that bacterial cells are themselves preserved when mineral formation occurs within and/or at cell surfaces Gérard et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Preservation in microbial mats: mineralization by a talc-like phase of a fish embedded in a microbial sarcophagus

et al. 2015

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Microbial mats have been repeatedly suggested to promote early fossilization of macroorganisms. Yet, experimental simulations of this process remain scarce. Here, we report results of 5 year-long experiments performed onfish carcasses to document the influence of microbial mats on mineral precipitation during early fossilization. Carcasses were initially placed on top of microbial mats. After 2 weeks, fish became coated by the mats forming a compact sarcophagus, which modified the microenvironment close to the corpses. Our results showed that these conditions favored the precipitation of a poorly crystalline silicate phase rich in magnesium. This talc-like mineral phase has been detected in three different locations within the carcasses placed in microbial mats for more than 4 years: (1) within inner tissues, colonized by several bacillary cells; (2) at the surface of bones of the upper face of the corpse buried in the mat; and (3) at the surface of several bones such as the dorsal fin which appeared to be gradually replaced by the Mg-silicate phase. This mineral phase has been previously shown to promote bacteria fossilization. Here we provide first experimental evidence that such Mg-rich phase can also be involved in exceptional preservation of animals.

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“…The pinkish layer with purple sulphur bacteria is a site in the mat where carbonates nucleate and grow, as observed frequently in the natural microbial mats from Lagoa Vermelha (van Lith et al 2003;Vasconcelos et al 2006) and in artificial microbial mats . As a proof that elemental sulphur is formed inside the cells, a pure culture of the isolated bacteria was investigated by SEM-EDAX, which showed clearly that the inclusions in the cells were pure sulphur (Fig.…”

Section: Artificial Anoxic Microbial Matsmentioning

confidence: 76%