Download or read book Physiology of Multiple Sulfur Isotope Fractionation During Microbial Sulfate Reduction written by Min Sub Sim and published by . This book was released on 2012 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial sulfate reduction (MSR) utilizes sulfate as an electron acceptor and produces sulfide that is depleted in heavy isotopes of sulfur relative to starting sulfate. The fractionation of S-isotopes is commonly used to trace the biogeochemical cycling of sulfur in nature, but a mechanistic understanding of factors that control the range of isotope fractionation is still lacking. This thesis investigates links between the physiology of sulfate reducing bacteria in pure cultures and multiple sulfur isotope (32, 33, 3434S, and 36S) fractionation during MSR in batch and continuous culture experiments. Experiments address the influence of nutrient and electron donor conditions, including organic carbon, nitrogen, and iron, in cultures of a newly isolated marine sulfate reducing bacterium (DMSS-1). An actively growing culture of DMSS-1 produced sulfide depleted in 34S by 6 to 66%o, depending on the availability and chemistry of organic electron donors. The magnitude of isotope effect correlated well with the cell specific sulfate reduction rate (csSRR), and the largest isotope effects occurred when cultures grew slowly on glucose, a recalcitrant organic substrate. These findings bridge the long-standing discrepancy between the upper limit for S-isotope effect in laboratory cultures and the corresponding observations in nature and indicate that the large (>46 %o) fractionation of S-isotopes does not unambiguously record the oxidative sulfurrecycling. When the availability of iron was limited, the increase in S-isotope fractionation was accompanied by a decrease in the cytochrome c content as well as csSRR. In contrast, growth in nitrogenlimited cultures increased both csSRR and S-isotope fractionation. The influence of individual enzymes and electron carriers involved in sulfate respiration on the fractionation of S-isotopes was also investigated in cultures of mutant strains of Desulfovibrio vulgaris Hildenborough. The mutant lacking Type I tetraheme cytochrome c3 fractionated 34S/32S ratio 50% greater relative to the wild type. The increasing S-isotope fractionation accompanied the evolution of H2 in the headspace and the decreasing csSRR. These results further demonstrate that the flow of electrons to terminal reductases imparts the primary control on the magnitude of the fractionation of S-isotopes, suggested by culture experiments using DMSS-1.
Download or read book The Consequences of Evolutionary Adaptation on the Sulfur Isotope Fractionation of Sulfate Reducing Microorganisms written by André Pellerin and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Sulfur metabolisms leave behind a record of their activity in the sulfur they utilize. This thesis seeks to advance our understanding of some of these processes with a particular focus on dissimilatory sulfate reduction. The multiple sulfur isotope composition of two porewater sulfate profiles in the anoxic marine sapropel of Mangrove Lake, Bermuda was investigated. The porewater sulfate profiles exhibit the distinct isotopic signatures of microbial sulfate reduction and sulfur reoxidation which simple diagenetic models can reproduce. The reoxidative cycle includes sulfide oxidation to elemental sulfur followed by the disproportionation of the elemental sulfur to sulfate and sulfide, and this process turns over from 50 to 80% of the sulfide produced by sulfate reduction. We suggest that the reoxidative S cycle in any environment can best be identified within two regions of the multiple sulfur isotope fractionation spectrum. Paper 1 is titled Mass-dependent sulfur isotopefractionation during reoxidative sulfur cycling: A case study from Mangrove Lake, Bermuda. The process of evolutionary adaptation has largely been assumed inconsequential on the sulfur isotopic fractionation produced during dissimilatory sulfate reduction and recorded in the isotope rock record. Yet, the diversity of sulfur isotope phenotypes displayed by species of sulfate reducing microorganisms isolated from modern environments amounts to strong evidence that evolutionary adaptation does matter. If this is the case, important information about the evolutionary history of DSR may be preserved in the rock record. However, the relationship between evolutionary adaptation and isotope phenotype is unexplored. To begin addressing this gap in knowledge, the impact of evolutionary adaptation on the fitness and sulfur isotopic phenotype of the dissimilatory sulfate reducer Desulfovibrio vulgaris Hildenborough (DvH) was investigated. The increases in fitness that were observed did not result in a change of the isotopephenotype. At least in the conditions of the experiment this result indicates that the isotopephenotype is not very sensitive to evolutionary adaptation on the hundreds of generations timescale. This suggests that lengthier timescales are necessary for evolutionary-driven divergence of the isotope phenotype. Paper 2 is titled Evolutionary adaptation of a sulfate reducing bacterium and its sulfur isotope phenotype. To address the issues raised in paper 2, pure cultures of Desulfomicrobium baculatm were evolved in batch culture for 300 generations. A greater than two fold increase in growth rate over the course of the experiment was measured as well as a change in isotope phenotype (??) from 15 to 12 %. The response of ?? to evolutionary adaptation resembles in some ways the isotopic response of physiological adaptations to changing environmental conditions. While in the narrow context of the environment where the evolutionary adaptation took place, the change in isotope phenotype is incontestable, it remains to be seen if this difference in isotope phenotype ismaintained across different growth environments. Paper 3 is titled "Evolutionary response of S isotope fractionation is predicted by phenotypic plasticity"." --
Download or read book On the Mechanisms of Sulfur Isotope Fractionation During Microbial Sulfate Reduction written by William Davie Leavitt and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underlying all applications of sulfur isotope analyses is our understanding of isotope systematics. This dissertation tests some fundamental assumptions and assertions, drawn from equilibrium theory and a diverse body of empirical work on biochemical kinetics, as applied to the multiple sulfur isotope systematics of microbial sulfate reduction. I take a reductionist approach, both in the questions addressed and experimental approaches employed. This allows for a mechanistic, physically consistent interpretation of geological and biological sulfur isotope records. The goal of my work here is to allow interpreters a more biologically, chemically and physically parsimonious framework to decipher the signals coded in modern and ancient sulfur isotope records.
Download or read book Microbial Connections Between the Subsurface Sulfur Cycle and Other Elemental Cycles written by Alexandra V. Turchyn and published by Frontiers Media SA. This book was released on 2018-11-16 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sulfur has many redox states and is a major metabolite in suboxic and anaerobic environments including, but not restricted to, marine and marginal marine sediments, the water column of oxygen minimum zones, salt marshes and oil wells. Microbially mediated redox cycling of sulfur typically comprises dissimilatory sulfate reduction (MSR), sulfide reoxidation, disproportionation and the oxidation and reduction of sulfur redox intermediates. These processes contribute to the degradation of organic matter, link the cycles of sulfur and carbon, control the production and consumption of methane and are critical for the long term budget of O2 in the atmosphere. Microbial and abiotic processes at redox interfaces also connect the sulfur cycle to the redox cycles of nitrogen, iron and other elements, producing distinctive geochemical and molecular signatures. Studies that couple microbiology with stable isotope geochemistry have informed interpretations of microbial sulfur cycling in modern and past environments. Laboratory-based studies and models of MSR have sought to understand the physiological and environmental controls of the magnitude of sulfur isotope fractionation. The fractionations of stable sulfur and oxygen isotopes during MSR are also used to track enzymatic activity during MSR and processes that oxidize sulfide in the presence of environmental oxidants. Outstanding questions in the field concern the importance of oxidative processes within the natural environment, the delivery of oxidants and carbon sources to the zones of sulfate reduction and the ability to detect or reconstruct oxidative processes from the chemical, isotopic, metagenomic, transcriptomic, proteomic and metabolomics profiles in the environment. Recent studies have emphasized the complex connections between sulfur and methane, iron, nitrogen and other elements. These links may involve the redox cycling of species that occur at concentrations difficult to detect by standard geochemical techniques or that are cycled at very rapid rates (cryptic cycles). Of particular interest is the use of isotope geochemistry to quantify links among various electron acceptors, including sulfate, ferric iron, and nitrate, during the anaerobic methane oxidation. For example, recent geochemical measurements have hinted that microbial sulfate reduction coupled to organic matter oxidation is mechanistically different to when sulfate reduction is coupled to methane oxidation. Recent studies have also suggested a possible contribution of a number of previously uncultured microbial groups in sulfur cycling in sulfidic environments, inspiring further studies of these organisms and their partnerships in anaerobic environments. This Research Topic highlights studies of microbial interactions, processes and communities that couple the sulfur cycle to the cycles of other elements in aphotic environments.
Download or read book Mechanisms of Sulfur Isotope Fractionation During Thermochemical Sulfate Reduction by Amino Acids written by Andrew Chorney and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The understanding of the evolution of the earth's early atmosphere has largely been based on the behavior of the multiple isotopes of sulfur. However experiments designed to mimic fractionation in both an oxygen poor atmosphere through SO2 photolysis and a presumably oxygen rich atmosphere though thermochemical sulfate reduction (TSR) have thus far been unable to confirm a mechanism capable of creating the mass independent fractionation of sulfur (MIF-S) signatures observed in Archean age rocks. This has created much controversy in how the MIF-S record is used to determine Archean environments. However large amounts of geochemical evidence suggest at least appreciable amounts of oxygen in the atmosphere and ocean at different stages through the Archean. This has motivated us to further explore TSR as a source of MIF-S through a rigorous investigation of how chemical speciation, experimental conditions, time, and rate effect sulfur isotope fractionation. Our results show the importance of initial sulfur redox state and chemistry, temperature, and organic reductant type in creating characteristic mass dependent and independent fractionations. Including previous TSR results (Watanabe et. al., 2009 and Oduro et. al., 2011) we report increased [delta]34S and [delta]36S fractionation in TSR products to 15.50[per mille symbol] and 1.5[per mille symbol] respectively and increased [delta]33S range from -.22 to 2.30[per mille symbol] in H2S largely through the use of mixtures of glycine and alanine. In sulfate we observe [delta]34S fractionation between 0.00 and 7.85[per mille symbol] and [delta]33S fractionation between -.15[per mille symbol] and 0.0[per mille symbol]. By quantifying fractionation amongst different sulfur bearing products produced during experiments and collected at experiment conclusions in addition to characterizing the effects due to various experimental conditions we are also able describe a schematic framework for the isotope effects during various steps of TSR. Fractionation from the magnetic isotope effect (MIE), the vibrational energy discontinuity effect (VEDE), first described for heterogeneous reactions by Lasaga et. al, 2008, and normal stable isotope mass dependently driven kinetic isotope effects (KIE) are utilized in this schematic to describe the experimental results. The MIE and VEDE are responsible for the MIF-S signatures observed in organic polysulfides and H2S at high temperatures. Additionally the effects of these mechanisms are greatly influenced by amino acid type, specifically in experiments that use a mixture of glycine and alanine. The VEDE and KIE are responsible for [delta]34S fractionation with the overall effect of producing sulfide depleted in 34S at lower temperatures. The interplay of these mechanisms is responsible for [delta]33S and [delta]34S trends observed in sulfides and sulfate samples. Based on this proposed schematic for sulfur isotope fractionation during TSR major trends and features in the Archean [delta]33S vs. [delta]34S and [delta]36S vs. [delta]33S record can be interpreted. Our results confirm that MIF-S signatures observed in natural samples are a product of depositional environment and possibly reflect characteristics of reactions specific to sedimentary basin conditions and early earth's tectonic regime.
Download or read book A Revised Monod type Rate Law Predicting Variable Sulfur Isotope Fractionation Factors as a Function of Microbial Sulfate Reduction Rate written by Max Greene Giannetta and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microbial Sulfur Metabolism written by Christiane Dahl and published by Springer Science & Business Media. This book was released on 2007-09-09 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: This revealing book details recent developments in the study of the relationship between sulfur and the microbial agents that affect its metabolism. In recent years, new methods have been applied to study the biochemistry and molecular biology of reactions of the global sulfur cycle, the microorganisms involved and their physiology, metabolism and ecology. These activities have uncovered fascinating new insights for the understanding of aerobic and anaerobic sulfur metabolism.
Download or read book Influence of Sulfate Concentration on Stable Isotope Fractionation During Sulfate Reduction by Natural Populations of Sulfate Reducing Bacteria written by Michael B. Gade and published by . This book was released on 2002 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stable Isotope Geochemistry written by John W. Valley and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 43 of Reviews in Mineralogy and Geochemistry follows the 1986 Reviews in Mineralogy (Vol. 16) in approach but reflects significant changes in the field of Stable Isotope Geochemistry. In terms of new technology, new sub-disciplines, and numbers of researchers, the field has changed more in the past decade than in any other since that of its birth. Unlike the 1986 volume, which was restricted to high temperature fields, this book covers a wider range of disciplines. However, it would not be possible to fit a comprehensive review into a single volume. Our goal is to provide state-of-the-art reviews in chosen subjects that have emerged or advanced greatly since 1986. This volume was prepared for Short Course on Stable Isotope Geochemistry presented November 2-4, 2001 in conjunction with the annual meetings of the Geological Society of America in Boston, Massachusetts.
Download or read book Deconstructing the Dissimilatory Sulfate Reduction Pathway written by Emma Bertran and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Dissimilatory sulfate reduction plays a significant role in shaping the sulfur isotope composition of sedimentary sulfides. These, in turn, record the evolution of Earth's surface redox state. The fractionation produced by this microbial metabolism is controlled by the flux of sulfur through the respiratory reaction network and the isotopic effect associated with each component reaction. Although the net isotope fractionations of this metabolism have been well studied, unraveling the isotopic influence of each component of its pathway is still a challenge. The sulfite to sulfide reduction step is a particularly complicated one. Its biochemistry is not fully understood and the associated isotope effect is inferred from fractionations associated with the entire metabolic pathway or from in-vitro experiments with cell-free extracts.
Download or read book Fractionation of the Stable Isotopes of Sulfur by Microorganisms with Particular Reference to the Sulfate reducing Bacteria written by Galen Everts Jones and published by . This book was released on 1955 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biochemical Adaptation written by Pater W. Hochachka and published by Princeton University Press. This book was released on 2014-07-14 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses biochemical adaptation to environments from freezing polar oceans to boiling hot springs, and under hydrostatic pressures up to 1,000 times that at sea level. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.
Download or read book Calculation of Equilibrium Constants for Isotopic Exchange Reactions written by Jacob Bigeleisen and published by . This book was released on 1947 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Isotopic Constraints on Earth System Processes written by Kenneth W. W. Sims and published by John Wiley & Sons. This book was released on 2022-04-20 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using isotopes as a tool for understanding Earth processes From establishing the absolute age of the Earth to providing a stronger understanding of the nexus between geology and life, the careful measurement and quantitative interpretation of minor variations in the isotopic composition of Earth’s materials has provided profound insight into the origins and workings of our planet. Isotopic Constraints on Earth System Processes presents examples of the application of numerous different isotope systems to address a wide range of topical problems in Earth system science. Volume highlights include: examination of the natural fractionation of non-traditional stable isotopes utilizing isotopes to understand the origin of magmas and evolution of volcanic systems application of isotopes to interrogate and understand Earth’s Carbon and Oxygen cycles examination of the geochemical and hydrologic processes that lead to isotopic fractionation application of isotopic reactive transport models to decipher hydrologic and biogeochemical processes The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.
Download or read book Isotope Fractionation by Sulfate reducing Bacteria written by Renata C. Cummins and published by . This book was released on 2011 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sulphur Isotope Fractionation in Modern and Ancient Sediments written by Thi Hao Bui and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Modern and ancient sediments are complex biogeochemical systems where multiple sulphur isotopes may be useful in tracing previously unseen processes. Multiple sulphur isotope signatures of pore water sulphate from methane-rich marine sediments indicate different microbial pathways involved in the overall sulphur cycling. Particularly in chapter 2, we found that sulphate reduction is the only microbial process controlling the sulphur cycling at station 12 but at station 5 up to 60% of sulphide produced from sulphate reduction re-oxidizes back to sulphate. We are only able to tell this difference with multiple sulphur isotopes. (Chapter 2- Hidden sulphur cycle stimulates the microbial methane biofilter in deep marine sediments)Beside biological processes, transport of material may cause isotope fractionation. We analyze multiple sulphur isotope composition of dissolved sulphate and sulphide when these ions diffused through an acrylamide gel column. The experimental results showed that the diffusion-associated isotope fractionation of ion sulphate is insignificant within the study size (~20 cm length) but the diffusion-associated isotope fractionation of ion sulphide is clearly observable (34[alpha] = 0.9990±0.0005). With that fractionation factor, when sulphide diffuses 1 meter away from the source, it is at least 10[per mil] lighter than the original isotope composition. (Chapter 3 - Sulphur isotope effects of [("SO")]_4^(2-) and [("HS")]_^- diffusion in water). In chapter 4, we apply multiple sulphur isotope techniques to study the sulphur cycling during the end-Permian mass extinction. Minor sulphur isotope signature suggests the mixing of at least two distinct sulphur sources during that time period. We have proposed possible sulphur sources even though further studies are required in order to identify exactly which sources contributed to the sulphur enrichment at Permian-Triassic period (Chapter 4 - Sulphur and carbon isotope records across the terrestrial Permian-Triassic (P-T) boundary)." --
Download or read book Sulfur Biogeochemistry written by Jan P. Amend and published by Geological Society of America. This book was released on 2004 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
