scholarly journals The Record of Environmental and Microbial Signatures in Ancient Microbialites: The Terminal Carbonate Complex from the Neogene Basins of Southeastern Spain

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 276
Author(s):  
Raphaël Bourillot ◽  
Emmanuelle Vennin ◽  
Christophe Dupraz ◽  
Aurélie Pace ◽  
Anneleen Foubert ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Microbial Mats ◽  
Significant Proportion ◽  
Sedimentary Basins ◽  
High Energy ◽  
Carbonate Complex ◽  
Carbonate Production ◽  
Southeastern Spain ◽  
Hypersaline Water ◽  
Terminal Carbonate Complex

The Messinian microbialites of the Terminal Carbonate Complex (TCC) from the Neogene basins of southeastern Spain show both diversified morphologies and an excellent preservation of primary microbial microstructures. Their stratigraphic architecture, fabric (micro-, meso-, and macro-fabric), and mineralogical composition were investigated in eight localities from three sedimentary basins of southeastern Spain: The Sorbas and Bajo Segura basins and the Agua Amarga depression. Two recurrent microbialite associations were distinguished. Laterally linked low relief stromatolites predominated in Microbialite Association 1 (MA1), which probably formed in low energy lagoons or lakes with fluctuating normal marine to hypersaline water. The microfabrics of MA1 reflected the predominance of microbially induced/influenced precipitation of carbonates and locally (Ca)-Mg-Al silicates. Microbialite Association 2 (MA2) developed in high energy wave and tidal influenced foreshore to shoreface, in normal marine to hypersaline water. High-relief buildups surrounded by mobile sediment (e.g., ooids or pellets) dominated in this environment. MA2 microbialites showed a significant proportion of thrombolitic mesofabric. Grain-rich microfabrics indicated that trapping and binding played a significant role in their accretion, together with microbially induced/influenced carbonate precipitation. The stratigraphic distribution of MA1 and MA2 was strongly influenced by water level changes, the morphology and nature of the substratum, and exposure to waves. MA1 favorably developed in protected areas during third to fourth order early transgression and regression phases. MA2 mostly formed during the late transgressions and early regressions in high energy coastal areas, often corresponding to fossil coral reefs. Platform scale syn-sedimentary gypsum deformation and dissolution enhanced microbial carbonate production, microbialites being thicker and more extended in zones of maximum deformation/dissolution. Microbial microstructures (e.g., microbial peloids) and microfossils were preserved in the microbialites. Dolomite microspheres and filaments showed many morphological similarities with some of the cyanobacteria observed in modern open marine and hypersaline microbialites. Dolomite potentially replaced a metastable carbonate phase during early diagenesis, possibly in close relationship with extracellular polymeric substances (EPS) degradation. Double-layered microspheres locally showed an inner coating made of (Ca)-Mg-Al silicates and carbonates. This mineral coating could have formed around coccoid cyanobacteria and indicated an elevated pH in the upper part of the microbial mats and a potential dissolution of diatoms as a source of silica. Massive primary dolomite production in TCC microbialites may have resulted from enhanced sulfate reduction possibly linked to the dissolving gypsum that would have provided large amounts of sulfate-rich brines to microbial mats. Our results open new perspectives for the interpretation of ancient microbialites associated with major evaporite deposits, from microbe to carbonate platform scales.

scholarly journals Obesity epidemic in urban Tanzania: a public health calamity in an already overwhelmed and fragmented health system

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Pedro Pallangyo ◽  
Zabella S. Mkojera ◽  
Naairah R. Hemed ◽  
Happiness J. Swai ◽  
Nsajigwa Misidai ◽  
...  
Keyword(s):  
Public Health ◽  
Fast Food ◽  
Associated Factors ◽  
Significant Proportion ◽  
High Energy ◽  
Dar Es Salaam ◽  
Overweight And Obesity ◽  
Sub Saharan Africa ◽  
Smoking History ◽  
Healthy Weight

Abstract Background Worldwide, the epidemiological and demographic transitions have resulted in nutrition shift characterized by an increased consumption of high energy fast food products. In just over 3 decades, overweight and obesity rates have nearly tripled to currently affecting over a third of the global population. Notwithstanding the ever present under-nutrition burden, sub Saharan Africa (SSA) is witnessing a drastic escalation of overweight and obesity. We aimed to explore the prevalence and associated factors for obesity among residents of Dar es Salaam city in Tanzania. Methods Participants from this study were recruited in a community screening conducted during the Dar es Salaam International Trade Fair. Sociodemographic and clinical data were gathered using a structured questionnaire during enrollment. Dietary habits and anthropometric measurements were assessed using standard methods. All statistical analyses utilized STATA v11.0 software. Pearson Chi square and Student’s T-test were used to compare categorical and continuous variables respectively. Logistic regression analyses were used to assess for factors associated with BMI ≥ 25. All tests were 2-sided and p < 0.05 was used to denote a statistical significance. Results A total of 6691 participants were enrolled. The mean age was 43.1 years and males constituted 54.2% of all participants. Over two-thirds of participants were alcohol consumers and 6.9% had a positive smoking history. 88.3% of participants were physically inactive, 4.7% had a history of diabetes mellitus and 18.1% were known to have elevated blood pressure. Overweight and obesity were observed in 34.8 and 32.4% of participants respectively. Among overweight and obese participants, 32.8% had a misperception of having a healthy weight. Age ≥ 40, female gender, a current working status, habitual breakfast skipping, poor water intake, high soft drink consumption, regular fast food intake, low vegetable and fruit consumption, alcohol consumption and hypertension were found to be independent associated factors for obesity. Conclusion Amidst the ever present undernutrition in SSA, a significant proportion of participants had excess body weight. Concomitantly, the rates of physical inactivity and unhealthy eating are disproportionately high in Dar es Salaam. In view of this, community-based and multilevel public health strategies to promote and maintain healthy eating and physical activity require an urgent step-up in urban Tanzania.

Reservoir analog model for oolite-microbialite sequences, Miocene terminal carbonate complex, Spain

AAPG Bulletin ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 2035-2057 ◽  
Author(s):  
Christopher J. Lipinski ◽  
Evan K. Franseen ◽  
Robert H. Goldstein
Keyword(s):  
Carbonate Complex ◽  
Analog Model ◽  
Terminal Carbonate Complex

Settlement down again patterns of a carbonated platform following up a sedimentary crisis : example of the middle-late Jurassic boundary in the southeastern part of the Paris Basin

2004 ◽  
Vol 175 (3) ◽  
pp. 289-302 ◽  
Author(s):  
Sébastien Lorin ◽  
Philippe Courville ◽  
Pierre-Yves Collin ◽  
Jacques Thierry ◽  
Anthony Tort
Keyword(s):  
Late Jurassic ◽  
Regional Scale ◽  
High Energy ◽  
Depositional Environments ◽  
Low Energy ◽  
Tectonic Activity ◽  
Paris Basin ◽  
Marine Waters ◽  
Carbonate Production ◽  
Lithostratigraphic Units

Abstract Following a sedimentary crisis which begins in the late Lower Callovian and spans all the early Oxfordian, the settlement down patterns of a platform with carbonated sedimentation are analysed in a southeastern area of the Paris Basin (fig. 1). Ten lithostratigraphic units (reefal formations, associated bioclastic facies and marly distal lateral facies ; fig. 2) are defined (fig. 3). New ammonite and brachiopod faunas, collected in situ, allow to date accurately the sedimentary units with a precision matching an ammonite subzone of the standard bio-chronostratigraphic scale (fig. 4) of the middle-late Oxfordian (from the Parandieri Subzone, at the base of the Transversarium Zone, to the Planula Subzone, at the top of the Planula Zone). The sedimentologic analysis coupled with the study of the benthic and pelagic faunal communities allow to define twelve type-facies (tabl. I and II). Regrouped into three associations, these characterise depositional environments which occur in succession, following three platform models (fig. 5). As witnesses of the evolution of the accomodation/sedimentation ratio, the resulting time succession of sedimentary bodies shows a depositional dynamics organised into three sequence tracks (fig. 5 and 6) : – a retrogradation phase is characterised by a moderately deep and open platform, dominated by low energy and marly sedimentation, which ranges from the Middle Oxfordian (Plicatilis Zone and Transversarium Zone) to the lowermost late Oxfordian (Bifurcatus Zone) ; – during the late Oxfordian (Bimammatum Zone, from the Semimammatum Subzone to the Bimammatum Subzone) an aggradation phase corresponds to the installation of three successive shallow platforms with contrasted morphology. Indicating the re-initiation of carbonated production, these platforms are well limited and represent high energy shallows with reef buildings, which lateraly grade into dismantling bioclastic faciès, then secondly and more laterally again into low energy and medium deep marly facies ; – the upper part of the late Oxfordian (Hauffianum Subzone, in the uppermost Bimammatum Zone, and Planula Zone) shows the wide extent of a low energy and morphologically very little contrasted distal platform. This one has a high potential of carbonated production characterised by bioclastic, oolitic and micritic facies which illustrate a progradation phase ; such a phase proceeds in the early Kimmeridgian. The collected data and the corresponding phenomenons pointed out on this area of the southeastern border of the Paris Basin are discussed and replaced in the general framework of the sedimentary, biologic, palaeogeographic and palaeoclimatic events henceforth recognised at the middle-late Jurassic boundary on the peri-Tethyan intracratonic domains of western Europe. The demise of the carbonate production seems to be correlated with a global cooling of both marine waters and atmosphere, which is considered as a limiting factor. During the Middle Oxfordian, the re-initiation of carbonate production with the developement of reef buildings should correspond to a large scale warming of the marine waters still observed elswhere on the Russian Platform, in the North Sea and in the Paris Basin. However, the geographic distribution and the chronologic succession of the facies and deduced palaeoenvironments is probably equally related to a synsedimentary tectonic activity which operates as a favorable factor at both a local and regional scale.

scholarly journals A New Niche for Anoxygenic Phototrophs as Endoliths

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
Daniel Roush ◽  
Estelle Couradeau ◽  
Brandon Guida ◽  
Susanne Neuer ◽  
Ferran Garcia-Pichel
Keyword(s):  
High Throughput Sequencing ◽  
Microbial Mats ◽  
Hot Springs ◽  
Significant Proportion ◽  
Anoxygenic Phototrophic Bacteria ◽  
Major Type ◽  
Carbonate Platforms ◽  
Content Type ◽  
Wide Range ◽  
Isla De Mona

ABSTRACTAnoxygenic phototrophic bacteria (APBs) occur in a wide range of aquatic habitats, from hot springs to freshwater lakes and intertidal microbial mats. Here, we report the discovery of a novel niche for APBs: endoliths within marine littoral carbonates. In a study of 40 locations around Isla de Mona, Puerto Rico, and Menorca, Spain, 16S rRNA high-throughput sequencing of endolithic community DNA revealed the presence of abundant phylotypes potentially belonging to well-known APB clades. Anad hocphylogenetic classification of these sequences enabled us to refine the assignments more stringently. Even then, all locations contained such putative APBs, often reaching a significant proportion of all phototrophic sequences. In fact, in some 20% of samples, their contribution exceeded that of oxygenic phototrophs, previously regarded as the major type of endolithic microbe in carbonates. The communities contained representatives of APBs in theChloroflexales, various proteobacterial groups, andChlorobi. The most abundant phylotypes varied with geography: on Isla de Mona,RoseiflexusandChlorothrix-related phylotypes dominated, whereas those related toErythrobacterwere the most common in Menorca. The presence of active populations of APBs was corroborated through an analysis of photopigments: bacteriochlorophylls were detected in all samples, bacteriochlorophyllcandabeing most abundant. We discuss the potential metabolism and geomicrobial roles of endolithic APBs. Phylogenetic inference suggests that APBs may be playing a role as photoheterotrophs, adding biogeochemical complexity to our understanding of such communities. Given the global extent of coastal carbonate platforms, they likely represent a very large and unexplored habitat for APBs.IMPORTANCEEndolithic microbial communities from carbonates, which have been explored for over 2 centuries in predominantly naturalistic studies, were thought to be primarily composed of eukaryotic algae and cyanobacteria. Our report represents a paradigm shift in this regard, at least for the marine environment, demonstrating the presence of ubiquitous and abundant populations of APBs in this habitat. It raises questions about the role of these organisms in the geological dynamics of coastal carbonates, including coral reefs.

Skeletal carbonate productivity and phosphogenesis at the lower–middle Cambrian transition of Scania, southern Sweden

2009 ◽  
Vol 147 (1) ◽  
pp. 59-76 ◽  
Author(s):  
J. JAVIER ÁLVARO ◽  
PER AHLBERG ◽  
NIKLAS AXHEIMER
Keyword(s):  
Primary Productivity ◽  
Microbial Mats ◽  
High Energy ◽  
Nutrient Supply ◽  
Energy Conditions ◽  
Southern Sweden ◽  
Middle Cambrian ◽  
Alum Shale ◽  
Shale Formation ◽  
Reducing Environment

AbstractThe lower–middle Cambrian transitional interval of Scania is largely represented by condensed limestone beds, lithostratigraphically grouped in the Gislöv Formation (1–5.7 m thick), and the Forsemölla and Exsulans Limestone beds (lower part of the Alum Shale Formation, up to 4 m thick). The strata display a combination of skeletal carbonate productivity, episodic nucleation of phosphate hardground nodules, and polyphase reworking recorded on a platform bordering the NW corner of Baltica. The shell accumulations can be subdivided into three deepening-upward parasequences, separated by distinct erosive unconformities. The parasequences correspond biostratigraphically to the Holmia kjerulfi, Ornamentaspis? linnarssoni and Ptychagnostus gibbus zones, the latter two generally being separated by a stratigraphic gap that includes the middle Cambrian Acadoparadoxides oelandicus Superzone. Except for the Exsulans Limestone, the carbonates reflect development of a prolific epibenthic biota, dominated by filter-feeding nonreefal chancelloriid–echinoderm–sponge meadows, rich in trilobites and brachiopods, and which were subjected to high-energy conditions. The absence of microbial mats or veneers encrusting the erosive surfaces of these event-concentration low-relief shoal complexes may be related to long hiatal episodes resulting in microboring proliferation. High levels of nutrient supply resulted in high primary productivity, eutrophic conditions, glauconite precipitation, phosphogenesis (in some case microbially mediated) and microendolithic infestation. An early-diagenetic mildly reducing environment is suggested by the presence of authigenic (subsequently reworked) pyrite, which contrasts with the syndepositional normal oxygenated conditions reflected by macroburrowing and the abundance of benthic fossils.

Barite (BaSO4) biomineralization at Flybye Springs, a cold sulphur spring system in Canada's Northwest Territories

2007 ◽  
Vol 44 (6) ◽  
pp. 835-856 ◽  
Author(s):  
Sandy M Bonny ◽  
Brian Jones
Keyword(s):  
Northwest Territories ◽  
Extracellular Polymeric Substances ◽  
Microbial Mats ◽  
Outer Cell ◽  
Flow Paths ◽  
Average Temperature ◽  
Passive Adsorption ◽  
Spring System ◽  
Sulphur Spring ◽  
Reducing Bacteria

The Flybye Springs, Northwest Territories, consist of 10 active vents and numerous small seeps that discharge sulphide- and barium-rich spring waters at an average temperature 8.5 °C. Oxidation of sulphide to sulphate drives precipitation of stellate and platy barite microcrystals in the proximal flow paths. Downstream, and in vent- and tributary-fed ponds, barite is precipitated among streamer and mat forming colonies of sulphur-tolerant microbes, including Thiothrix, Beggiatoa, Thioploca, Chromatium, Oscillatoria, fungi (dominantly Penicillium), and unicellular sulphate reducing bacteria. These microbes mediate barite saturation by adjusting redox gradients and via passive adsorption of barium ions to cell surfaces and extracellular polymeric substances. Passive biomineralization produces barite laminae in floating microbial mats, nanometric coatings, and micrometric encrustations around microbial cells and filaments, and local permineralization of Thiothrix, Beggiatoa, and Oscillatoria outer cell walls. Intracellular barium enrichment and (or) metabolic sulphur oxidation may be important to "active biomineralization" that produces nanometric barite globules on the tips of fungal hyphae, barite-filled cell cavities in Beggiatoa and Thiothrix, and baritized sulphur globules. Degradation of biomineralized cells generates detrital "microfossils," including barite tunnels, layered cylinders, solid cylindrical grains and chains of barite beads. The diversity of inorganic and biomineralized barite in the Flybye Springs flow path highlights the influence of ambient chemistry, microbial metabolism, and cellular structure on barite solubility and on the taphonomy of microfossils preserved in barite.

scholarly journals The influence of microbial mats on travertine precipitation in active hydrothermal systems (Central Italy)

2020 ◽  
Author(s):  
Giovanna Della Porta ◽  
Joachim Reitner
Keyword(s):  
Microbial Communities ◽  
Extracellular Polymeric Substances ◽  
Microbial Mats ◽  
Central Italy ◽  
Hydrothermal Systems ◽  
Crystal Nucleation ◽  
Anoxygenic Phototrophic Bacteria ◽  
Physico Chemical ◽  
Slope System ◽  
Aluminium Silicates

ABSTRACTThe study of hydrothermal travertines contributes to the understanding of the interaction between physico-chemical processes and the role played by microbial mats and biofilms in influencing carbonate precipitation. Three active travertine sites were investigated in Central Italy to identify the types of carbonate precipitates and the associated microbial mats at varying physico-chemical parameters. Carbonate precipitated fabrics at the decimetre- to millimetre-scale and microbial mats vary with decreasing water temperature: a) at high temperature (55-44°C) calcite or aragonite crystals precipitate on microbial mats of sulphide oxidizing, sulphate reducing and anoxygenic phototrophic bacteria forming filamentous streamer fabrics, b) at intermediate temperature (44-40°C), rafts, coated gas bubbles and dendrites are associated with Spirulina cyanobacteria and other filamentous and rod-shaped cyanobacteria, c) low temperature (34-33°C) laminated crusts and oncoids in a terraced slope system are associated with diverse Oscillatoriales and Nostocales filamentous cyanobacteria, sparse Spirulina and diatoms. At the microscale, carbonate precipitates are similar in the three sites consisting of prismatic calcite (40-100 μm long, 20-40 μm wide) or acicular aragonite crystals organized in radial spherulites, overlying or embedded within biofilm EPS (Extracellular Polymeric Substances). Microsparite and sparite crystal size decreases with decreasing temperature and clotted peloidal micrite dominates at temperatures < 40°C, also encrusting filamentous microbes. Carbonates are associated with gypsum and Ca-phosphate crystals; EPS elemental composition is enriched in Si, Al, Mg, Ca, P, S and authigenic aluminium-silicates form aggregates on EPS.This study confirms that microbial communities in hydrothermal travertine settings vary as a function of temperature. Carbonate precipitate types at the microscale do not vary considerably, despite different microbial communities suggesting that travertine precipitation, driven by CO2 degassing, is influenced by biofilm EPS acting as template for crystal nucleation (EPS-mediated mineralization) and affecting the fabric types, independently from specific microbial metabolism.

scholarly journals Botryoidal and Spherulitic Aragonite in Carbonates Associated with Microbial Mats: Precipitation or Diagenetic Replacement Product?

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuzhu Ge ◽  
Giovanna Della Porta ◽  
Chelsea L. Pederson ◽  
Stephen W. Lokier ◽  
René Hoffmann ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Microbial Mats ◽  
Salt Lake ◽  
Pore Space ◽  
Depositional Environments ◽  
Formation Mechanisms ◽  
Microbial Biofilms ◽  
Marine Carbonate ◽  
Fluid Properties ◽  
Underlying Mechanisms

Similar carbonate fabrics may result from different pathways of precipitation and diagenetic replacement. Distinguishing the underlying mechanisms leading to a given carbonate fabric is relevant, both in terms of an environmental and diagenetic interpretation. Prominent among carbonate fabrics are aragonite botryoids and spherulites, typically interpreted as direct seawater precipitates and used as proxies for fluid properties and depositional environments. This study investigated μm to mm-scale Holocene botryoidal and spherulitic aragonite from marine and non-marine carbonate settings associated with microbial mats, and reports two distinct formation mechanisms: 1) early diagenetic replacement, and 2) primary precipitation via nanocrystal aggregation. In the intertidal microbial mats of Khawr Qantur (Abu Dhabi), botryoidal and spherulitic aragonite are replacement products of heavily micritized bioclasts. To form the botryoidal and spherulitic aragonite, skeletal rods and needles, resulting from disintegration of micritized bioclasts, recrystallize into nanocrystals during early marine diagenesis. These nanocrystals then grow into fibrous crystals, forming botryoidal and spherulitic aragonite. In the lacustrine microbial bioherms of the hypersaline Great Salt Lake (United States) and in the hydrothermal travertines of Bagni San Filippo (Italy), botryoidal and spherulitic aragonite evolve from nanocrystals via precipitation. The nanocrystals are closely associated with extracellular polymeric substances in microbial biofilms and aggregate to form fibrous crystals of botryoidal and spherulitic aragonite. The studied fabrics form a portion of the bulk sediment and show differences in terms of their formation processes and petrological features compared to the often larger (few mm to over 1 m) botryoidal and spherulitic aragonite described from open-marine reefal cavities. Features shown here may represent modern analogues for ancient examples of carbonate depositional environments associated with microbialites. The implication of this research is that botryoidal and spherulitic aragonite associated with microbial mats are relevant in paleoenvironmental interpretations, but must be combined with a detailed evaluation of their formation process. Care must be taken as the term “botryoidal and spherulitic aragonite” may in fact include, from the viewpoint of their nucleation and formation mechanism, similar fabrics originated from different pathways. At present, it seems unclear to which degree the μm to mm-scale botryoids and spherulites described here are comparable to their cm-to dm-size counterparts precipitated as cements in the open pore space of reefal environments. However, it is clear that the investigation of ancient botryoidal and spherulitic aragonite must consider the possibility of an early diagenetic replacement origin of these precipitates.

scholarly journals The Messinian stromatolites of the Sierra del Colmenar (Western Mediterranean): facies characterization and sedimentological interpretation

2018 ◽  
Author(s):  
Patricio Guillermo Villafañe ◽  
Hugo Corbí ◽  
Carlos Cónsole-Gonella ◽  
Francisco Javier Ruiz-Sánchez
Keyword(s):  
Physical Environment ◽  
Environmental Changes ◽  
Western Mediterranean ◽  
Carbonate Complex ◽  
Se Spain ◽  
Internal Morphology ◽  
Facies Characterization ◽  
Bajo Segura Basin ◽  
Terminal Carbonate Complex ◽  
Northern Sector

The Messinian stromatolites belonging to the Terminal Carbonate Complex unit, from the northern sector of the Bajo Segura Basin (CAM section, Sierra del Colmenar, SE Spain) have been studied. To understand the direct relationship between the morphologies of the stromatolites and their deposition context in order to reconstruct the environmental conditions for their growth, a detailed study of their architecture, external morphology and internal morphology was carried out (macrofabric and microfabric). The stromatolites are made up of domic bodies laterally linked to each other, generating a macrostructure (bioherms) with lateral continuity. This stromatolitic macrostructure presents variations in its internal morphology, giving rise to seven subfacies product of the environmental changes experienced during the growth of the microbial bushes. The stromatolites are arranged parallel of coastline acting as paleogeographic barriers to reduce the physical stress of the environment. Although in general lines suggests a coastal environment, restricted and shallow for the formation of the whole level, the variation in internal morphology is evidence of minor changes in the physical environment.

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