scholarly journals Sedimentary pyrite sulfur isotope compositions preserve signatures of the surface microbial mat environment in sediments underlying low‐oxygen cyanobacterial mats

Geobiology ◽  
2021 ◽  
Author(s):  
Maya L. Gomes ◽  
Judith M. Klatt ◽  
Gregory J. Dick ◽  
Sharon L. Grim ◽  
Kathryn I. Rico ◽  
...  
Keyword(s):  
Sulfur Isotope ◽  
Microbial Mat ◽  
Low Oxygen ◽  
Cyanobacterial Mats ◽  
Sedimentary Pyrite

scholarly journals The formation mechanisms of sedimentary pyrite nodules determined by trace element and sulfur isotope microanalysis

2019 ◽  
Vol 259 ◽  
pp. 53-68 ◽  
Author(s):  
Daniel Gregory ◽  
Indrani Mukherjee ◽  
Stephanie L. Olson ◽  
Ross R. Large ◽  
Leonid V. Danyushevsky ◽  
...  
Keyword(s):  
Trace Element ◽  
Sulfur Isotope ◽  
Formation Mechanisms ◽  
Sedimentary Pyrite

scholarly journals Pyrite Textures, Trace Elements and Sulfur Isotope Chemistry of Bijaigarh Shales, Vindhyan Basin, India and Their Implications

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 588
Author(s):  
Indrani Mukherjee ◽  
Mihir Deb ◽  
Ross R. Large ◽  
Jacqueline Halpin ◽  
Sebastien Meffre ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Sulfur Isotope ◽  
Volcanic Rocks ◽  
Central India ◽  
High Energy ◽  
Vindhyan Basin ◽  
Mean Values ◽  
Fine Grained ◽  
Sedimentary Pyrite

The Vindhyan Basin in central India preserves a thick (~5 km) sequence of sedimentary and lesser volcanic rocks that provide a valuable archive of a part of the Proterozoic (~1800–900 Ma) in India. Here, we present an analysis of key sedimentary pyrite textures and their trace element and sulfur isotope compositions in the Bijaigarh Shale (1210 ± 52 Ma) in the Vindhyan Supergroup, using reflected light microscopy, LA-ICP-MS and SHRIMP-SI, respectively. A variety of sedimentary pyrite textures (fine-grained disseminated to aggregates, framboids, lags, and possibly microbial pyrite textures) are observed reflecting quiet and strongly anoxic water column conditions punctuated by occasional high-energy events (storm incursions). Key redox sensitive or sensitive to oxidative weathering trace elements (Co, Ni, Zn, Mo, Se) and ratios of (Se/Co, Mo/Co, Zn/Co) measured in sedimentary pyrites from the Bijaigarh Shale are used to infer atmospheric redox conditions during its deposition. Most trace elements are depleted relative to Proterozoic mean values. Sulfur isotope compositions of pyrite, measured using SHRIMP-SI, show an increase in δ34S as we move up stratigraphy with positive δ34S values ranging from 5.9‰ (lower) to 26.08‰ (upper). We propose limited sulphate supply caused the pyrites to incorporate the heavier isotope. Overall, we interpret these low trace element signatures and heavy sulfur isotope compositions to indicate relatively suppressed oxidative weathering on land during the deposition of the Bijaigarh Shale.

scholarly journals Omics-Inferred Partitioning and Expression of Diverse Biogeochemical Functions in a Low-O 2 Cyanobacterial Mat Community

mSystems ◽  
2021 ◽  
Author(s):  
Sharon L. Grim ◽  
Alexander A. Voorhies ◽  
Bopaiah A. Biddanda ◽  
Sunit Jain ◽  
Stephen C. Nold ◽  
...  
Keyword(s):  
Natural History ◽  
Chemical Evolution ◽  
Bacterial Species ◽  
Low Oxygen ◽  
Cyanobacterial Mats ◽  
Geological Time ◽  
Cyanobacterial Mat ◽  
Oxygen Conditions

Cyanobacterial mats are dense communities of microorganisms that contain photosynthetic cyanobacteria along with a host of other bacterial species that play important yet still poorly understood roles in this ecosystem. Although such cyanobacterial mats were critical agents of Earth’s biological and chemical evolution through geological time, little is known about how they function under the low-oxygen conditions that characterized most of their natural history.

scholarly journals Extant Earthly Microbial Mats and Microbialites as Models for Exploration of Life in Extraterrestrial Mat Worlds

Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 883
Author(s):  
Bopaiah Biddanda ◽  
Anthony Weinke ◽  
Ian Stone ◽  
Scott Kendall ◽  
Phil Hartmeyer ◽  
...  
Keyword(s):  
Microbial Mats ◽  
Life Forms ◽  
Microbial Mat ◽  
Lake Huron ◽  
Low Oxygen ◽  
Extraterrestrial Life ◽  
Microbial Life ◽  
High Carbonate ◽  
Sulfur Oxidizing ◽  
Bodies Of Water

As we expand the search for life beyond Earth, a water-dominated planet, we turn our eyes to other aquatic worlds. Microbial life found in Earth’s many extreme habitats are considered useful analogs to life forms we are likely to find in extraterrestrial bodies of water. Modern-day benthic microbial mats inhabiting the low-oxygen, high-sulfur submerged sinkholes of temperate Lake Huron (Michigan, USA) and microbialites inhabiting the shallow, high-carbonate waters of subtropical Laguna Bacalar (Yucatan Peninsula, Mexico) serve as potential working models for exploration of extraterrestrial life. In Lake Huron, delicate mats comprising motile filaments of purple-pigmented cyanobacteria capable of oxygenic and anoxygenic photosynthesis and pigment-free chemosynthetic sulfur-oxidizing bacteria lie atop soft, organic-rich sediments. In Laguna Bacalar, lithification by cyanobacteria forms massive carbonate reef structures along the shoreline. Herein, we document studies of these two distinct earthly microbial mat ecosystems and ponder how similar or modified methods of study (e.g., robotics) would be applicable to prospective mat worlds in other planets and their moons (e.g., subsurface Mars and under-ice oceans of Europa). Further studies of modern-day microbial mat and microbialite ecosystems can add to the knowledge of Earth’s biodiversity and guide the search for life in extraterrestrial hydrospheres.

scholarly journals Coupled trace element and SIMS sulfur isotope geochemistry of sedimentary pyrite: Implications on pyrite growth of Caixiashan Pb–Zn deposit

2019 ◽  
Vol 10 (6) ◽  
pp. 2177-2188 ◽  
Author(s):  
Dengfeng Li ◽  
Huayong Chen ◽  
Xiaoming Sun ◽  
Yu Fu ◽  
Qiaofen Liu ◽  
...  
Keyword(s):  
Trace Element ◽  
Sulfur Isotope ◽  
Isotope Geochemistry ◽  
Sedimentary Pyrite

scholarly journals Microbial Diversity of a Heavily Polluted Microbial Mat and Its Community Changes following Degradation of Petroleum Compounds

2002 ◽  
Vol 68 (4) ◽  
pp. 1674-1683 ◽  
Author(s):  
Raeid M. M. Abed ◽  
Nimer M. D. Safi ◽  
Jürgen Köster ◽  
Dirk de Beer ◽  
Yasser El-Nahhal ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Diversity ◽  
Significant Role ◽  
Bacterial Communities ◽  
Bacterial Population ◽  
Microbial Mats ◽  
Community Response ◽  
Microbial Mat ◽  
Cyanobacterial Mats ◽  
Community Changes

ABSTRACT We studied the microbial diversity of benthic cyanobacterial mats inhabiting a heavily polluted site in a coastal stream (Wadi Gaza) and monitored the microbial community response induced by exposure to and degradation of four model petroleum compounds in the laboratory. Phormidium- and Oscillatoria-like cyanobacterial morphotypes were dominant in the field. Bacteria belonging to different groups, mainly the Cytophaga-Flavobacterium-Bacteriodes group, the γ and β subclasses of the class Proteobacteria, and the green nonsulfur bacteria, were also detected. In slurry experiments, these communities efficiently degraded phenanthrene and dibenzothiophene completely in 7 days both in the light and in the dark. n-Octadecane and pristane were degraded to 25 and 34% of their original levels, respectively, within 7 days, but there was no further degradation until 40 days. Both cyanobacterial and bacterial communities exhibited noticeable changes concomitant with degradation of the compounds. The populations enriched by exposure to petroleum compounds included a cyanobacterium affiliated phylogenetically with Halomicronema. Bacteria enriched both in the light and in the dark, but not bacteria enriched in any of the controls, belonged to the newly described Holophaga-Geothrix-Acidobacterium phylum. In addition, another bacterial population, found to be a member of green nonsulfur bacteria, was detected only in the bacteria treated in the light. All or some of the populations may play a significant role in metabolizing the petroleum compounds. We concluded that the microbial mats from Wadi Gaza are rich in microorganisms with high biodegradative potential.

Revisiting Ediacaran sulfur isotope chemostratigraphy with in situ nanoSIMS analysis of sedimentary pyrite

Geology ◽  
2021 ◽  
Author(s):  
Wei Wang ◽  
Yongliang Hu ◽  
A. Drew Muscente ◽  
Huan Cui ◽  
Chengguo Guan ◽  
...  
Keyword(s):  
Sulfur Isotope ◽  
Secondary Ion Mass Spectrometry ◽  
Size Change ◽  
Seawater Chemistry ◽  
Carbonate Associated Sulfate ◽  
Seawater Sulfate ◽  
Nanosims Analysis ◽  
Secondary Ion ◽  
Sedimentary Pyrite

Reconstructions of ancient sulfur cycling and redox conditions commonly rely on sulfur isotope measurements of sedimentary rocks and minerals. Ediacaran strata (635–541 Ma) record a large range of values in bulk sulfur isotope difference (Δ34S) between carbonate-associated sulfate (δ34SCAS) and sedimentary pyrite (δ34Spy), which has been interpreted as evidence of marine sulfate reservoir size change in space and time. However, bulk δ34Spy measurements could be misleading because pyrite forms under syngenetic, diagenetic, and metamorphic conditions, which differentially affect its isotope signature. Fortunately, these processes also impart recognizable changes in pyrite morphology. To tease apart the complexity of Ediacaran bulk δ34Spy measurements, we used scanning electron microscopy and nanoscale secondary ion mass spectrometry to probe the morphology and geochemistry of sedimentary pyrite in an Ediacaran drill core of the South China block. Pyrite occurs as both framboidal and euhedral to subhedral crystals, which show largely distinct negative and positive δ34Spy values, respectively. Bulk δ34Spy measurements, therefore, reflect mixed signals derived from a combination of syndepositional and diagenetic processes. Whereas euhedral to subhedral crystals originated during diagenesis, the framboids likely formed in a euxinic seawater column or in shallow marine sediment. Although none of the forms of pyrite precisely record seawater chemistry, in situ framboid measurements may provide a more faithful record of the maximum isotope fractionation from seawater sulfate. Based on data from in situ measurements, the early Ediacaran ocean likely contained a larger seawater sulfate reservoir than suggested by bulk analyses.

HIF1-α-Mediated Gene Expression Induced by Vitamin B1 Deficiency

2013 ◽  
Vol 83 (3) ◽  
pp. 188-197 ◽  
Author(s):  
Rebecca L. Sweet ◽  
Jason A. Zastre
Keyword(s):  
Gene Expression ◽  
Thiamine Deficiency ◽  
Glucose Transporter ◽  
Neuroblastoma Cell ◽  
Hypoxia Inducible Factor ◽  
Clinical Manifestations ◽  
Vitamin B1 ◽  
Low Oxygen ◽  
Glucose Transporter 1 ◽  
Metabolic Intermediates

It is well established that thiamine deficiency results in an excess of metabolic intermediates such as lactate and pyruvate, which is likely due to insufficient levels of cofactor for the function of thiamine-dependent enzymes. When in excess, both pyruvate and lactate can increase the stabilization of the hypoxia-inducible factor 1-alpha (HIF-1α) transcription factor, resulting in the trans-activation of HIF-1α regulated genes independent of low oxygen, termed pseudo-hypoxia. Therefore, the resulting dysfunction in cellular metabolism and accumulation of pyruvate and lactate during thiamine deficiency may facilitate a pseudo-hypoxic state. In order to investigate the possibility of a transcriptional relationship between hypoxia and thiamine deficiency, we measured alterations in metabolic intermediates, HIF-1α stabilization, and gene expression. We found an increase in intracellular pyruvate and extracellular lactate levels after thiamine deficiency exposure to the neuroblastoma cell line SK-N-BE. Similar to cells exposed to hypoxia, there was a corresponding increase in HIF-1α stabilization and activation of target gene expression during thiamine deficiency, including glucose transporter-1 (GLUT1), vascular endothelial growth factor (VEGF), and aldolase A. Both hypoxia and thiamine deficiency exposure resulted in an increase in the expression of the thiamine transporter SLC19A3. These results indicate thiamine deficiency induces HIF-1α-mediated gene expression similar to that observed in hypoxic stress, and may provide evidence for a central transcriptional response associated with the clinical manifestations of thiamine deficiency.

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