Formation and calcification of modern gypsum-dominated stromatolites, EMISAL, Fayium, Egypt

Taher, Amany G.

doi:10.1007/s10347-014-0405-5

Cited by 14 publications

(17 citation statements)

References 50 publications

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“…While discussion of these parameters is beyond the scope of the present study, it is expected that spatial trends in these parameters would be likely observed in our dataset as well. Beyond the Puquios, gradients in environmental conditions have been linked to mineral precipitation in other modern and ancient extreme environments, such as the salt works at Guerrero Negro 67 – 69 , the EMISAL salt works in Egypt 70 , 71 , and the Messinian evaporite deposits 59 . Such extreme conditions typically subject resident biota to wide fluctuations in salinity, as well as temperature, pH, dissolved oxygen, total dissolved solids and redox potential 72 , 73 .…”

Section: Discussionmentioning

confidence: 99%

Electrical conductivity as a driver of biological and geological spatial heterogeneity in the Puquios, Salar de Llamara, Atacama Desert, Chile

Reid

Oehlert

Suosaari

et al. 2021

Sci Rep

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Reputed to be the driest desert in the world, the Atacama Desert in the Central Andes of Northern Chile is an extreme environment with high UV radiation, wide temperature variation, and minimum precipitation. Scarce lagoons associated with salt flats (salars) in this desert are the surface expression of shallow groundwater; these ponds serve as refugia for life and often host microbial communities associated with evaporitic mineral deposition. Results based on multidisciplinary field campaigns and associated laboratory examination of samples collected from the Puquios of the Salar de Llamara in the Atacama Desert during austral summer provide unprecedented detail regarding the spatial heterogeneity of physical, chemical, and biological characteristics of these salar environments. Four main lagoons (‘Puquios’) and more than 400 smaller ponds occur within an area less than 5 km2, and are characterized by high variability in electrical conductivity, benthic and planktonic biota, microbiota, lagoon bottom type, and style of mineral deposition. Results suggest that electrical conductivity is a driving force of system heterogeneity. Such spatial heterogeneity within the Puquios is likely to be expanded with temporal observations incorporating expected seasonal changes in electrical conductivity. The complexity of these Andean ecosystems may be key to their ability to persist in extreme environments at the edge of habitability.

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Section: Discussionmentioning

confidence: 99%

Electrical conductivity as a driver of biological and geological spatial heterogeneity in the Puquios, Salar de Llamara, Atacama Desert, Chile

Reid

Oehlert

Suosaari

et al. 2021

Sci Rep

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“…Present-day examples of subaqueous gypsum-dominated microbialites (Fig. 16a-e and Fig. 3b) are found in hypersaline environments around the globe, such as the Gotomeer on the island of Bonaire in the Netherlands Antilles (Kobluk and Crowford 1990), the Guerrero Negro sabkha and saltern system in Mexico (Vogel et al, 2009;, the hypersaline lagoon of the Archipelago Los Roques in Venezuela (Petrash et al, 2012), several salt ponds in Egypt (Taher et al, 1995;Alik-Bik et al, 2011;Taher, 2014), the salinas of Sawda Nathil in Qatar (Strohmenger and Jameson, 2018), and the salars in the Atacama desert and High Andes (e.g. Ercilla Herrero, 2019).…”

Section: Mineralization In the Presence Of Prokaryotic Microorganismsmentioning

confidence: 99%

Calcium sulfate precipitation pathways in natural and engineered environments

2019

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The solution-mediated formation of calcium sulfate minerals, i.e. gypsum, anhydrite and bassanite, is a common process in both natural and engineered settings. It plays a key role in the global sulfur cycle and serves as an indicator of past environmental conditions on Earth and Mars. Products relying on the crystallization of these minerals have been employed since antiquity, and today they are an essential part of a wide array of industrial applications. Accordingly, the fundamental aspects of calcium sulfate mineralization have been the focus of intensive research during the past century. However, a recent flurry of studies addressing alternative, i.e. nonclassical, nucleation and growth mechanisms has spurred a revisit of the precipitation pathway of the most common phase, gypsum. The newly obtained data sketch a far more complex picture of the mineralization process than previously assumed. This has important consequences for the interpretation of calcium sulfate deposits, both from a geochemical and industrial point of view. In order to shed light on this issue, we discuss in this review both recent and long-standing observations of abiotic formation routes of calcium sulfate minerals as a function of the physicochemical solution properties. By integrating both the classical and non-classical perspectives on crystallization we put forward a unified model for calcium sulfate crystallization. Using this model, we (re)-evaluate the phase stability and transformations taking place in the CaSO 4-H 2 O system. Next, we look into the formation of calcium sulfate minerals occurring in close association with the biosphere. Employing the abiotic case scenario as a benchmarking tool, the possible influence and/or control exerted by biological activity (and its byproducts) on the precipitation pathway is critically reviewed. Finally, we point out the central issues that need to be resolved if we wish to fully understand and control the formation of calcium sulfate solids in natural and engineered environments.

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“…Beyond Andean microbial ecosystems, extreme environments have been observed in other modern and ancient hypersaline lagoons, lakes in arid settings, sabkha environments, and anthropogenically-driven evaporite depositional settings, such as the salt works at Guerrero Negro [69][70][71] and the EMISAL salt works in Egypt 72,73 . Such extreme conditions typically subject resident biota to wide uctuations in temperature, salinity, pH, dissolved oxygen, total dissolved solids and redox potential 74,75 .…”

Section: Discussionmentioning

confidence: 99%

A Multidisciplinary Evaluation of Spatial Heterogeneity in the Puquios of the Salar de Llamara, Atacama Desert, Northern Chile

Oehlert

Suosaari

et al. 2021

Preprint

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The Atacama Desert, Central Andes of Northern Chile, is an extreme environment characterized by high UV radiation, wide temperature variation, minimum precipitation and is reputed as the driest desert in the world. Scarce lagoons associated with salt flats (salars) in this desert are the surface expression of shallow groundwater which serve as refugia for life, and often host microbial communities associated with evaporitic mineral deposition. Recent investigations of the Puquios of the Salar de Llamara in the Atacama Desert based on multidisciplinary field studies provide unprecedented detail regarding the spatial heterogeneity of physical, chemical, and biological characteristics of such saline lake environments. Four main lagoons (‘Puquios’) and more than 400 smaller ponds, occur in an area less than 5 km2, are characterized by high variability in electrical conductivity, benthic and planktonic biota and microbiota, lagoon bottom type, and style of mineral deposition. The heterogeneity of system parameters as observed spatially in the Puquios is likely to be expanded with temporal observations incorporating seasonality. Results provide new insight into the complexity of these Andean ecosystems, which may be key to resilience in extreme environments at the edge of habitability.

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Formation and calcification of modern gypsum-dominated stromatolites, EMISAL, Fayium, Egypt

Cited by 14 publications

References 50 publications

Electrical conductivity as a driver of biological and geological spatial heterogeneity in the Puquios, Salar de Llamara, Atacama Desert, Chile

Electrical conductivity as a driver of biological and geological spatial heterogeneity in the Puquios, Salar de Llamara, Atacama Desert, Chile

Calcium sulfate precipitation pathways in natural and engineered environments

A Multidisciplinary Evaluation of Spatial Heterogeneity in the Puquios of the Salar de Llamara, Atacama Desert, Northern Chile

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