scholarly journals Role ofGeitlerinemasp. DE2011 andScenedesmussp. DE2009 as Bioindicators and Immobilizers of Chromium in a Contaminated Natural Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Laia Millach ◽  
Antoni Solé ◽  
Isabel Esteve
Keyword(s):  
Metal Concentration ◽  
Natural Environment ◽  
Extracellular Polymeric Substances ◽  
Microbial Mats ◽  
Ebro Delta ◽  
Phototrophic Microorganisms ◽  
High Viability

The aim of this work was to study the potential of the two phototrophic microorganisms, both isolated from Ebro Delta microbial mats, to be used as bioindicators and immobilizers of chromium. The results obtained indicated that (i) the Minimum Metal Concentration (MMC) significantly affecting Chlorophyllaintensity inGeitlerinemasp. DE2011 andScenedesmussp. DE2009 was 0.25 µM and 0.75 µM, respectively, these values being lower than those established by current legislation, and (ii)Scenedesmussp. DE2009 was able to immobilize chromium externally in extracellular polymeric substances (EPS) and intracellularly in polyphosphate (PP) inclusions. Additionally, this microorganism maintained high viability, including at 500 µM. Based on these results, we postulate thatGeitlerinemasp. DE2011 andScenedesmussp. DE2009 are good chromium-indicators of cytotoxicity and, further, thatScenedesmussp. DE2009 plays an important role in immobilizing this metal in a contaminated natural environment.

Morphological responses to nitrogen stress deficiency of a new heterotrophic isolated strain of Ebro Delta microbial mats

PROTOPLASMA ◽  
2018 ◽  
Vol 256 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Eduard Villagrasa ◽  
Neus Ferrer-Miralles ◽  
Laia Millach ◽  
Aleix Obiol ◽  
Jordi Creus ◽  
...  
Keyword(s):  
Microbial Mats ◽  
Ebro Delta ◽  
Nitrogen Stress ◽  
Morphological Responses

Distribution of types of microbial mats at the Ebro Delta, Spain

Biosystems ◽  
1993 ◽  
Vol 31 (2-3) ◽  
pp. 135-144 ◽  
Author(s):  
Ricardo Guerrero ◽  
Jordi Urmeneta ◽  
Giorgio Rampone
Keyword(s):  
Microbial Mats ◽  
Ebro Delta

Oxygenic Photosynthesis and Respiratory Activity in Microbial Mats of the Ebro Delta, Spain, by Oxygen Exchange Method

1998 ◽  
Vol 37 (3) ◽  
pp. 151-155 ◽  
Author(s):  
Jordi Urmeneta ◽  
Óscar Alcoba ◽  
Efrén Razquín ◽  
Elena Tarroja ◽  
Antoni Navarrete ◽  
...  
Keyword(s):  
Microbial Mats ◽  
Respiratory Activity ◽  
Oxygen Exchange ◽  
Ebro Delta ◽  
Oxygenic Photosynthesis ◽  
Exchange Method

Fatty acids, hydrocarbons, sterols and alkenones of microbial mats from coastal ecosystems of the ebro delta

Ophelia ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 189-194 ◽  
Author(s):  
Tirso García de Oteyza ◽  
Jordi F. Lopez ◽  
Joan O. Grimalt
Keyword(s):  
Fatty Acids ◽  
Microbial Mats ◽  
Coastal Ecosystems ◽  
Ebro Delta

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 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.

Isolation and Characterization of Cyanobacteria from Microbial Mats of the Ebro Delta, Spain

2003 ◽  
Vol 46 (3) ◽  
pp. 199-204 ◽  
Author(s):  
Jordi Urmeneta ◽  
Antoni Navarrete ◽  
Javier Huete ◽  
Ricardo Guerrero
Keyword(s):  
Microbial Mats ◽  
Ebro Delta ◽  
Isolation And Characterization

The sabkhas of Qatar: modern analogues for studying early life on Earth and on Mars

2020 ◽  
Author(s):  
Tomaso Bontognali ◽  
Franziska Blattmann ◽  
Zulfa Al Disi ◽  
Hamad Al Saad Al Kuwari ◽  
Zach DiLoreto ◽  
...  
Keyword(s):  
Early Life ◽  
Extracellular Polymeric Substances ◽  
Microbial Mats ◽  
Natural Environments ◽  
Intertidal Zones ◽  
Anoxygenic Phototrophs ◽  
Nucleation Sites ◽  
Uppermost Layer ◽  
Upper Intertidal ◽  
Life On Earth

&lt;p&gt;The study of early life on Earth and the search for life on Mars often includes investigations of modern analogues: natural environments that share similarities to what we hypothesize may have existed on the early Earth and early Mars. The study of modern analogues provides key information on how biosignatures are formed and preserved, which is essential for interpreting the geological record. Research conducted in recent years in various modern sabkhas located along the coast of Qatar have demonstrated that these extreme evaporitic environments represent an inspirational gold mine for the field of geobiology and astrobiology.&lt;/p&gt;&lt;p&gt;The intertidal zones of the Qatari sabkhas are typically colonized by microbial mats. Their presence leads to the formation of Microbially Influenced Sedimentary Structures (MISS). Examples of studied MISS include polygonal, domical, blistered, tufted and crinkled microbial mats. We discuss biological vs. physiochemical factors responsible for their formation, as well as their fossilization potential. These MISS often occur in a precise sequence along a transect from the lower to the upper intertidal zone. We propose that a MISS sequence represents a stronger morphological biosignature than a single MISS. The community composition of some of the studied mats revealed an uppermost layer dominated by anoxygenic phototrophs. We propose that such mats represent a particularly good analogue for studying life in the Early Archean, a time when the cyanobacteria that usually dominate the uppermost photo-oxic layer of most modern mats probably did not exist.&lt;/p&gt;&lt;p&gt;Besides influencing sediment morphology, the extracellular polymeric substances (EPS) constituting the mats serve as nucleation sites for the precipitation of authigenic minerals. Among these possible precipitates, our research focused on microbially influenced Mg-rich carbonates and Mg-rich silicates. Linking these minerals to a microbial process is of particular interest in view of the forthcoming rover missions to Mars (i.e., ExoMars and Mars 2020). Indeed, orbital spectral analyses revealed the presence of Mg-rich clays and Mg-rich carbonates in the surroundings of the proposed landing sites. It will be exciting to test the hypothesis that, on Mars, some of these minerals may have formed at low temperatures from liquid water and may, therefore, represent a target phase for the investigation of biosignatures.&lt;/p&gt;

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