Carbon isotope equilibration during sulphate-limited anaerobic oxidation of methane

Yoshinaga, Marcos Y.; Holler, Thomas; Goldhammer, Tobias; Wegener, Gunter; Pohlman, John W.; Brunner, Benjamin; Kuypers, Marcel M. M.; Hinrichs, Kai‐Uwe; Elvert, Marcus

doi:10.1038/ngeo2069

Cited by 162 publications

(179 citation statements)

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“…The seep sediments used in these experiments were selected because they (or adjacent cores) were shown to have active net anaerobic oxidation of methane; however, the methane concentration results from our experiments suggest some additional, if slight, production of methane of about 100 μM in all nonkilled bottles (Fig. 1B), maybe due to back reaction of AOM process, as suggested by Holler et al (47) and Yoshinaga et al (62). It seems also that methane was released by diffusion from the slurries to the headspace in all bottles, explaining the increase in methane concentration after the initial first day measurement also in the killed bottles (63).…”

Section: Resultsmentioning

confidence: 52%

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Sivan

Antler

Turchyn

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

123

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Seep sediments are dominated by intensive microbial sulfate reduction coupled to the anaerobic oxidation of methane (AOM). Through geochemical measurements of incubation experiments with methane seep sediments collected from Hydrate Ridge, we provide insight into the role of iron oxides in sulfate-driven AOM. Seep sediments incubated with 13 C-labeled methane showed cooccurring sulfate reduction, AOM, and methanogenesis. The isotope fractionation factors for sulfur and oxygen isotopes in sulfate were about 40‰ and 22‰, respectively, reinforcing the difference between microbial sulfate reduction in methane seeps versus other sedimentary environments (for example, sulfur isotope fractionation above 60‰ in sulfate reduction coupled to organic carbon oxidation or in diffusive sedimentary sulfate-methane transition zone). The addition of hematite to these microcosm experiments resulted in significant microbial iron reduction as well as enhancing sulfate-driven AOM. The magnitude of the isotope fractionation of sulfur and oxygen isotopes in sulfate from these incubations was lowered by about 50%, indicating the involvement of iron oxides during sulfate reduction in methane seeps. The similar relative change between the oxygen versus sulfur isotopes of sulfate in all experiments (with and without hematite addition) suggests that oxidized forms of iron, naturally present in the sediment incubations, were involved in sulfate reduction, with hematite addition increasing the sulfate recycling or the activity of sulfur-cycling microorganisms by about 40%. These results highlight a role for natural iron oxides during bacterial sulfate reduction in methane seeps not only as nutrient but also as stimulator of sulfur recycling.redox | anaerobic respiration | deep-sea | methanotrophy | ANME archaea M icrobial dissimilatory processes generate energy through the decomposition of substrates, whereas assimilatory processes use substrates for intracellular biosynthesis of macromolecules. The most known and energetically favorable dissimilatory process is the oxidation of organic carbon coupled to oxygen as terminal electron acceptor (Eq. 1). In sediments with a high supply of organic carbon, oxygen can be depleted within the upper few millimeters, leading to anoxic conditions deeper in the sediment column. Under these conditions, microbial dissimilatory processes are coupled to the reduction of a series of other terminal electron acceptors besides oxygen (1). The largest free-energy yields are associated with nitrate reduction (denitrification), followed by manganese and iron oxide reduction, and then sulfate reduction. Due to the high concentration of sulfate in the ocean, dissimilatory bacterial sulfate reduction (Eq. 2) is responsible for the majority of organic matter oxidation in marine sediments (2). Below the depth of sulfate depletion, traditionally the only presumed process is methanogenesis (methane production), where its main pathways are fermentation of organic matter, mainly acetate (Eq. 3), or the reduction of carbon di...

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Section: Resultsmentioning

confidence: 52%

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Sivan

Antler

Turchyn

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

123

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“…However, multiple isotopically discriminating steps/reactions are commonly considered in models and interpretations of isotopic fractionations in other biogeochemical processes. Examples include carbon fixation (e.g., Farquhar et al, 1989); methanogenesis and methanotrophy (e.g., Valentine et al, 2004;Yoshinaga et al, 2014); sulfate reduction (e.g., Rees, 1973;Farquhar et al, 2003); and nitrification (e.g., Casciotti et al, 2010;Buchwald and Casciotti, 2010). To demonstrate the feasibility of these sorts of frameworks to describe our experimental data, we derived a simplified model with two potentially isotopically discriminating steps during O 2 reduction.…”

Section: Multiple Isotopically Discriminating Steps During O 2 Reductionmentioning

confidence: 99%

Effects of temperature and carbon source on the isotopic fractionations associated with O2 respiration for 17O/16O and 18O/16O ratios in E. coli

Stolper

Fischer

Bender

2018

Geochimica et Cosmochimica Acta

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Effects

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“…Previously, it was found that as the reversibility of methanogenesis decreased (controlled in part by levels of bioavailable H 2 ), both the δD and ∆ 13 CH 3 D values of the generated methane became lower or more negative ; similar behavior was found in ∆ 18 (Stolper et al, 2014a;Stolper et al, 2015). Because of the demonstrated high levels of reversibility of AOM (Holler et al, 2011) and the re-equilibration of 13 C/ 12 C ratios between methane and inorganic carbon at the sulfate-methane transition zone (Yoshinaga et al, 2014), it seems reasonable to speculate that AOM may produce clumped isotope signatures distinct from those of methanogenesis (Stolper et al, 2015). In particular, the expression of a combination of kinetic and equilibrium isotope effects may be observed, such that the observed ∆ 13 (Table 4.2) suggests that potentially, microbially-mediated oxidation of methane produces only a small and predictable range of clumped isotopologue fractionations.…”

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confidence: 83%

“…Thus, clumped isotopologue data also assist in diagnosing presence or absence of isotope exchange during enzymatic abstraction of H from methane by MMO, and are consistent with a minor (not detectable) degree of reversibility for this process. The minor degree of reversibility indicated by the data for aerobic methane oxidation here contrasts sharply with the anaerobic oxidation of methane (AOM), an oxidation process in which much greater degrees of reversibility 4For example, when methane effuses through a small orifice, γ (when defined as the ratio of the isotopologue fractionation factor for have been demonstrated using carbon and hydrogen isotopes (Holler et al, 2011;Yoshinaga et al, 2014). The environmental implications are discussed in § 4.4.2.2.…”

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confidence: 92%

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The geochemistry of methane isotopologues

Wang¹

2017

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This thesis documents the origin, distribution, and fate of methane and several of its isotopic forms on Earth. Using observational, experimental, and theoretical approaches, I illustrate how the relative abundances of 12 CH 4 , 13 CH 4 , 12 CH 3 D, and 13 CH 3 D record the formation, transport, and breakdown of methane in selected settings.Chapter 2 reports precise determinations of 13 CH 3 D, a "clumped" isotopologue of methane, in samples collected from various settings representing many of the major sources and reservoirs of methane on Earth. The results show that the information encoded by the abundance of 13 CH 3 D enables differentiation of methane generated by microbial, thermogenic, and abiogenic processes. A strong correlation between clumped-and hydrogen-isotope signatures in microbial methane is identified and quantitatively linked to the availability of H 2 and the reversibility of microbially-mediated methanogenesis in the environment. Determination of 13 CH 3 D in combination with hydrogen-isotope ratios of methane and water provides a sensitive indicator of the extent of C-H bond equilibration, enables fingerprinting of methane-generating mechanisms, and in some cases, supplies direct constraints for locating the waters from which migrated gases were sourced. Chapter 3 applies this concept to constrain the origin of methane in hydrothermal fluids from sediment-poor vent fields hosted in mafic and ultramafic rocks on slow-and ultraslow-spreading mid-ocean ridges. The data support a hypogene model whereby methane forms abiotically within plutonic rocks of the oceanic crust at temperatures above ca. 300• C during respeciation of magmatic volatiles, and is subsequently extracted during active, convective hydrothermal circulation. Chapter 4 presents the results of culture experiments in which methane is oxidized in the presence of O 2 by the bacterium Methylococcus capsulatus strain Bath. The results show that the clumped isotopologue abundances of partially-oxidized methane can be predicted from knowledge of 13 C/ 12 C and D/H isotope fractionation factors alone.: Shuhei Ono, Ph.D. Acknowledgments I fear that this section will not do justice to the people I have not the space to thank individually. Alas, here goes. To those whose names are not specifically listed here, thank you too. I wish first to thank Shuhei Ono. The work this thesis represents could not have happened without his bold vision and the license to explore and question that working in his lab afforded. His unbridled optimism, breadth of scientific curiosity, personal integrity, and accessibility to his personnel are traits I one day hope to emulate. I thank him for his nonjudgmental yet appropriately measured support of many of my ideas-even those that led nowhere-, for believing in me even when I found it difficult to do so myself, and for teaching me to change pump oil, build vacuum lines, and drink Icelandic vodka.I also wish to thank my thesis committee members Jeff Seewald, Roger Summons, and John Pohlman, for their in...

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Carbon isotope equilibration during sulphate-limited anaerobic oxidation of methane

Cited by 162 publications

References 27 publications

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Effects of temperature and carbon source on the isotopic fractionations associated with O2 respiration for 17O/16O and 18O/16O ratios in E. coli

The geochemistry of methane isotopologues

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