scholarly journals Biological and geological characterization of modern biofilms and microbial mats and comparison with similar lithified structures in Colombian Cretaceous formations

2018 ◽  
Vol 22 (3) ◽  
pp. 159-168
Author(s):  
Daniela Osorio-Rodriguez ◽  
Carlos Alberto Sanchez-Quiñónez
Keyword(s):  
Microbial Mats ◽  
Extreme Environments ◽  
Microbial Mat ◽  
Mature Stage ◽  
Saline Environment ◽  
Symbiotic Relationships ◽  
Sedimentary Structures ◽  
Calcareous Rock ◽  
Siliciclastic Rock

Microorganisms may play an important role in the aggregation of sediments and the formation of sedimentary structures. Biofilms are microbial aggregates that, in a mature stage, can develop into microbial mats, fibrillar networks that irreversibly bind filaments of cyanobacteria and sediments, inside which it has been identified a stratification with functional groups of microorganisms that coexist, generate symbiotic relationships and potentially modify the characteristics of sediments and sedimentary rocks, particularly in extreme environments. In this work, filamentous cyanobacteria from biofilms of a lacustrine environment with intervals of flooding/desiccation and a saline environment, and a microbial mat from the Agua Caliente Thermal, El Rosal, Cundinamarca, are identified. In the biofilms, most cyanobacteria were found to belong to the Orden Oscillatoriales, while in the microbial mat cyanobacteria of the order Orden Nostocales were also recognized. Two rock samples isolated from the thermal which genesis was possibly influenced by the activity of cyanobacteria are described and classified. One of them, named R-1, is a calcareous rock inside which it was possible to differentiate biolaminations and an apparent dominance of biomineralization processes. This sample was both classified as a travertine and a microbial framestone with stromatolitic and thrombolytic texture. The second one, called R-2, is a siliciclastic rock classified as a mudstone and a microbial boundstone. Finally, a comparison between the sedimentary structures identified in those rocks with similar structures in the formations La Luna, Paja and Tetuán and the microbially-induced sedimentary structures (MISS) described in the literature is performed. Based on morphological resemblance, fibrillar networks identified locally in those formations are interpreted as possible biolaminations originated from the activity of cyanobacteria.

scholarly journals CARACTERIZAÇÃO DOS ESTROMATÓLITOS DA FORMAÇÃO CAPIRU (PROTEROZÓICO) NAS REGIÕES DE MORRO AZUL E MORRO GRANDE: LESTE DO PARANÁ

2002 ◽  
Vol 51 ◽  
Author(s):  
Sandra B. Guimarães ◽  
José Manoel Dos Reis Neto ◽  
Rossano B. L. Siqueira
Keyword(s):  
Cross Section ◽  
Microbial Mats ◽  
Microbial Control ◽  
Plane Parallel ◽  
Sedimentary Structures ◽  
Subaerial Exposure ◽  
Proterozoic Age

As regiões de Morro Azul e de Morro Grande no leste do Paraná abrigam exposições de estromatólitos, compostos por formas colunares e esteiras microbianas na Formação Capiru do Grupo Açungui de idade Proterozóica. Estes estromatólitos estão associados a metadolomitos e indicam provável controle microbiano na geração de dois diferentes grupos: a) esteiras microbianas na região de Morro Azul e b) estromatólitos colunares na região de Morro Grande. Os estromatólitos colunares possuem até 35 cm de altura por 15 cm de diâmetro, ocorrem em colunas simples ou ramificadas, geralmente associadas a estruturas sedimentares plano-paralelas e a marcas de onda. Em planta, os estromatólitos são elipsoidais a circulares, onde a laminação interna se apresenta de ondulada a moderadamente convexa. As esteiras microbianas são compostas de uma sucessão de lâminas finas associadas a estruturas características de exposição subaérea como tepees e gretas de contração. As características morfológicas das estruturas estromatolíticas, associadas às estruturas sedimentares observadas nas diferentes litofácies, permitem caracterizar distintos ambientes de plataforma para as duas regiões: para a de Morro Azul, um ambiente de supramaré; enquanto para a de Morro Grande, um ambiente variando de entremarés a inframaré. CHARACTERIZATION OF STROMATOLITES IN THE CAPIRU FORMATION (PROTEROZOIC) IN THE MORRO AZUL AND MORRO GRANDE REGIONS: EASTERN PARANÁ Abstract The Morro Azul (região de Morro Azul) and the Morro Grande (região de Morro Grande) regions in eastern Paraná contain columnar stromatolites and microbial mats in the Capiru Formation of the Açungui Group of Proterozoic age. These structures are associated with metadolomites, indicating probable microbial control in the formation of two different groups of stromatolites: a) columnar stromatolites in região de Morro Grande and b) microbial mats in the região de Morro Azul. Columnar stromatolites reach up to 35 cm in height and 15 cm in diameter as columns or branched generally associated with plane-parallel sedimentary structures and wave marks. In cross-section, the stromatolites are elliptical to circular, and the lamination is wavey to moderately convex. The microbial mats are composed of a succession of fine laminal associated with structures characteristic of subaerial exposure, such as tepees and mud cracks. The morphlogic features of the stromatolites and the observed sedimentary structures in the different lithofacies suggest distinct shelf environments for the two regions: for região de Morro Azul, a supratidal facies, while in the região de Morro Grande, an environment varying from intertidal to infratidal.

Modern and Holocene microbial mats and associated microbially induced sedimentary structures (MISS) on the southeastern coast of Tunisia (Mediterranean Sea)

2020 ◽  
pp. 1-21
Author(s):  
Rached Lakhdar ◽  
Mohamed Soussi ◽  
Rachida Talbi
Keyword(s):  
Spatial Distribution ◽  
High Frequency ◽  
Depositional Environment ◽  
Microbial Mats ◽  
Coastal Environment ◽  
Tidal Dynamics ◽  
Very High Frequency ◽  
Intertidal Zones ◽  
Sedimentary Structures ◽  
Very High

Abstract On the southeastern Tunisian coastline, very diverse living microbial mats colonize the lower supratidal and intertidal zones, and locally may extend into the upper infratidal zone. The interaction between the benthic cyanobacteria and their siliciclastic substratum leads to the development of several types of microbially induced sedimentary structures (MISS). The mapping of the microbial mats has allowed the identification of the types of MISS that characterize the different segments of the coastal environment. The modern microbial mats have been compared with those recorded at the top of the Holocene deposits, which are composed of biodegraded microbial black mats alternating with white laminae made of clastic and evaporitic sediments, indicative of very high frequency cycles of flood and drought. A hypothetic profile showing their occurrences along the different areas bordering the coastline is proposed as a guide for the reconstruction of the ancient depositional environment. The roles of tidal dynamics, storms, and climate in controlling their genesis and spatial distribution, are discussed and highlighted. The modern MISS of southeastern Tunisia are compared with their equivalents that are well documented through the different geological eras.

Combined Statistical-Mechanical Characterization of a Next Generation Textured PTFE for Extreme Environments

2018 ◽  
Author(s):  
Sannmit Shinde ◽  
Ali P. Gordon ◽  
Zachary Poust ◽  
Steve Pitolaj ◽  
Jim Drago ◽  
...  
Keyword(s):  
Extreme Environments ◽  
Viscoelastic Behavior ◽  
Ceramic Particle ◽  
Operating Conditions ◽  
Operating Environments ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Statistical Mechanical ◽  
Relaxation Responses

Pressurized vessels that transfer media from one location to another often contain a bolted connection. Gaskets are essential for these systems since they confer high levels of leak mitigation across of range of operating environments (i.e., internal pressure and temperature). The balance of both sealability and compressibility must be displayed in candidate gasket materials to be subjected to aggressive operating conditions. Historically, thin gauge gasket (i.e., 1/16” thick) confer high sealability while thick gaskets offer superior compressibility (i.e., 1/8”). Fabricated with skive cut, ceramic particle-reinforced PTFE, these materials display linear viscoelastic behavior that allow consolidation to occur. For example, GYLON® 3504 is filled with Aluminosilicate Microspheres, GYLON®3510 is filled with barium sulfate, respectively, to efficiently fill crevices along the surfaces of the flange. Novel textured PTFE gasket (3504 EPX and 3510 EPX) have been developed to simultaneously confer sealability and compressibility compared to flat products. A design of experiments (DoE) approach is applied to characterize the factors that influence load relaxation responses of the both candidate textured PTFE (dual-face honeycomb) and existing (flat) gasket styles. Using an instrumented test platform analyzed. A new parameter is presented to quantify gasket efficiency. The collection of efficiency measurement methods and approach to re-torque optimization convey a novel framework that designers can invoke to facilitate improved flange performance.

scholarly journals Sterol preservation in hypersaline microbial mats

2020 ◽  
Vol 17 (3) ◽  
pp. 649-666
Author(s):  
Yan Shen ◽  
Volker Thiel ◽  
Pablo Suarez-Gonzalez ◽  
Sebastiaan W. Rampen ◽  
Joachim Reitner
Keyword(s):  
Microbial Mats ◽  
Abiotic Factors ◽  
Total Sterol ◽  
Microbial Transformation ◽  
Microbial Mat ◽  
Hypersaline Lake ◽  
Central Pacific ◽  
Significant Drop ◽  
Subaerial Exposure ◽  
Benthic Ecosystems

Abstract. Microbial mats are self-sustaining benthic ecosystems composed of highly diverse microbial communities. It has been proposed that microbial mats were widespread in Proterozoic marine environments, prior to the emergence of bioturbating organisms at the Precambrian–Cambrian transition. One characteristic feature of Precambrian biomarker records is that steranes are typically absent or occur in very low concentrations. This has been explained by low eukaryotic source inputs, or degradation of primary produced sterols in benthic microbial mats (“mat-seal effect”). To better understand the preservational pathways of sterols in microbial mats, we analyzed freely extractable and carbonate-bound lipid fractions as well as decalcified extraction residues in different layers of a recent calcifying mat (∼1500 years) from the hypersaline Lake 2 on the island of Kiritimati, central Pacific. A variety of C27–C29 sterols and distinctive C31 4α-methylsterols (4α-methylgorgosterol and 4α-methylgorgostanol, biomarkers for dinoflagellates) were detected in freely extractable and carbonate-bound lipid pools. These sterols most likely originated from organisms living in the water column and the upper mat layers. This autochthonous biomass experienced progressive microbial transformation and degradation in the microbial mat, as reflected by a significant drop in total sterol concentrations, up to 98 %, in the deeper layers, and a concomitant decrease in total organic carbon. Carbonate-bound sterols were generally low in abundance compared to the freely extractable portion, suggesting that incorporation into the mineral matrix does not play a major role in the preservation of eukaryotic sterols in this mat. Likewise, pyrolysis of extraction residues suggested that sequestration of steroid carbon skeletons into insoluble organic matter was low compared to hopanoids. Taken together, our findings argue for a major mat-seal effect affecting the distribution and preservation of steroids in the mat studied. This result markedly differs from recent findings made for another microbial mat growing in the nearby hypersaline Lake 22 on the same island, where sterols showed no systematic decrease with depth. The observed discrepancies in the taphonomic pathways of sterols in microbial mats from Kiritimati may be linked to multiple biotic and abiotic factors including salinity and periods of subaerial exposure, implying that caution has to be exercised in the interpretation of sterol distributions in modern and ancient microbial mat settings.

scholarly journals Current Progress towards the Integration of Thermocouple and Chipless RFID Technologies and the Sensing of a Dynamic Stimulus

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1019
Author(s):  
Kevin Mc Gee ◽  
Prince Anandarajah ◽  
David Collins
Keyword(s):  
Radio Frequency Identification ◽  
Extreme Environments ◽  
Proof Of Concept ◽  
Rfid Technology ◽  
Barium Strontium ◽  
Chipless Rfid ◽  
Dynamic Stimulus ◽  
Frequency Identification ◽  
Scattering Response

To date, no printable chipless Radio Frequency Identification (RFID) sensor-related publications in the current literature discuss the possibility of thermocouple integration, particularly for the use in extreme environments. Furthermore, the effects of a time-dependent stimulus on the scattering parameters of a chipless RFID have never been discussed in the known literature. This work includes a review of possible methods to achieve this goal and the design and characterization of a Barium Strontium Titanate (BST) based VHF/UHF voltage sensing circuit. Proof-of-concept thermocouple integration was attempted, and subsequent testing was performed using a signal generator. These subsequent tests involved applying ramp and sinusoid voltage waveforms to the circuit and the characteristics of these signals are largely extracted from the scattering response. Overall conclusions of this paper are that thermocouple integration into chipless RFID technology is still a significant challenge and further work is needed to identify methods of thermocouple integration. With that being said, the developed circuit shows promise as being capable of being configured into a conventional chipless RFID DC voltage sensor.

scholarly journals Cultivation and Genomic, Nutritional, and Lipid Biomarker Characterization of Roseiflexus Strains Closely Related to Predominant In Situ Populations Inhabiting Yellowstone Hot Spring Microbial Mats

2010 ◽  
Vol 192 (12) ◽  
pp. 3033-3042 ◽  
Author(s):  
Marcel T. J. van der Meer ◽  
Christian G. Klatt ◽  
Jason Wood ◽  
Donald A. Bryant ◽  
Mary M. Bateson ◽  
...  
Keyword(s):  
National Park ◽  
Microbial Mats ◽  
Hot Spring ◽  
Small Subunit ◽  
Small Subunit Rrna ◽  
Anoxygenic Phototrophs ◽  
Lipid Biomarker ◽  
Genes Encoding

ABSTRACT Roseiflexus sp. strains were cultivated from a microbial mat of an alkaline siliceous hot spring in Yellowstone National Park. These strains are closely related to predominant filamentous anoxygenic phototrophs found in the mat, as judged by the similarity of small-subunit rRNA, lipid distributions, and genomic and metagenomic sequences. Like a Japanese isolate, R. castenholzii, the Yellowstone isolates contain bacteriochlorophyll a, but not bacteriochlorophyll c or chlorosomes, and grow photoheterotrophically or chemoheterotrophically under dark aerobic conditions. The genome of one isolate, Roseiflexus sp. strain RS1, contains genes necessary to support these metabolisms. This genome also contains genes encoding the 3-hydroxypropionate pathway for CO2 fixation and a hydrogenase, which might enable photoautotrophic metabolism, even though neither isolate could be grown photoautotrophically with H2 or H2S as a possible electron donor. The isolates exhibit temperature, pH, and sulfide preferences typical of their habitat. Lipids produced by these isolates matched much better with mat lipids than do lipids produced by R. castenholzii or Chloroflexus isolates.

scholarly journals Precipitation of Mn Oxides in Quaternary Microbially Induced Sedimentary Structures (MISS), Cape Vani Paleo-Hydrothermal Vent Field, Milos, Greece

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 536
Author(s):  
Stephanos P. Kilias ◽  
Magnus Ivarsson ◽  
Ernest Chi Chi Fru ◽  
Jayne E. Rattray ◽  
Håkan Gustafsson ◽  
...  
Keyword(s):  
Low Temperature ◽  
Hydrothermal Vent ◽  
Microbial Mats ◽  
Paramagnetic Resonance ◽  
Sedimentary Structures ◽  
Mn Oxide ◽  
Bedding Planes ◽  
Transmission Electron ◽  
Aerobic Methanotrophs ◽  
Hydrothermal Vent Field

Understanding microbial mediation in sediment-hosted Mn deposition has gained importance in low-temperature ore genesis research. Here we report Mn oxide ores dominated by todorokite, vernadite, hollandite, and manjiroite, which cement Quaternary microbially induced sedimentary structures (MISS) developed along bedding planes of shallow-marine to tidal-flat volcaniclastic sandstones/sandy tuffs, Cape Vani paleo-hydrothermal vent field, Milos, Greece. This work aims to decipher the link between biological Mn oxide formation, low-T hydrothermalism, and, growth and preservation of Mn-bearing MISS (MnMISS). Geobiological processes, identified by microtexture petrography, scanning and transmission electron microscopy, lipid biomarkers, bulk- and lipid-specific δ13Corganic composition, and field data, and, low-temperature hydrothermal venting of aqueous Mn2+ in sunlit shallow waters, cooperatively enabled microbially-mediated Mn (II) oxidation and biomineralization. The MnMISS biomarker content and δ13Corg signatures strongly resemble those of modern Mn-rich hydrothermal sediments, Milos coast. Biogenic and syngenetic Mn oxide precipitation established by electron paramagnetic resonance (EPR) spectroscopy and petrography, combined with hydrothermal fluid flow-induced pre-burial curing/diagenesis, may account for today’s crystalline Mn oxide resource. Our data suggests that MISS are not unique to cyanobacteria mats. Furthermore, microbial mats inhabited by aerobic methanotrophs may have contributed significantly to the formation of the MnMISS, thus widening the spectrum of environments responsible for marine Mn biometallogenesis.

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