Stable isotope fractionation during bacterial sulfate reduction is controlled by reoxidation of intermediates

Mangalo, Muna; Stichler, Willibald; Einsiedl, Florian

doi:10.1016/j.gca.2007.06.058

Cited by 76 publications

(76 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Oxygen isotopes in sulfate, however, have been shown to be strongly influenced by the oxygen isotope composition of water in which the bacteria are grown (41)(42)(43)(44)(45). The consensus is that, within the cell, sulfur compounds, such as sulfite, and water exchange oxygen atoms; some of these isotopically equilibrated molecules return to the extracellular sulfate pool.…”

Section: Significancementioning

confidence: 99%

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Sivan

Antler

Turchyn

et al. 2014

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

123

View full text Add to dashboard Cite

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...

show abstract

Section: Significancementioning

confidence: 99%

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Sivan

Antler

Turchyn

et al. 2014

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

123

View full text Add to dashboard Cite

show abstract

“…During bacterial sulphate reduction, the light sul− phur isotope ( 32 S) is preferentially metabolized causing the generated hydrogen sulphide to be isotopically light compared to the source sulphate (Kaplan and Rittenberg 1963). Laboratory and field studies show that a common sulphur iso− tope fractionation during this process ranges between 20 ‰ and 40 ‰ (Butler et al 2004;Mangalo et al 2007). The d 34 S values of pyrite in the Mount Wawel Forma− tion fall in a narrow range from −30 ‰ to −25 ‰, suggesting that the source sul− phate had isotopic composition roughly between 0 ‰ and +20 ‰.…”

Section: Discussionmentioning

confidence: 99%

Authigenic pyrite framboids in sedimentary facies of the Mount Wawel Formation (Eocene), King George Island, West Antarctica

Mozer¹

2010

Polish Polar Research

View full text Add to dashboard Cite

Pyrite framboids occur in loose blocks of plant−bearing clastic rocks related to volcano−sedimentary succession of the Mount Wawel Formation (Eocene) in the Dragon and Wanda glaciers area at Admiralty Bay, King George Island, West Antarctica. They were investigated by means of optical and scanning electron microscopy, energy−dispersive spectroscopy, X−ray diffraction, and isotopic analysis of pyritic sulphur. The results suggest that the pyrite formed as a result of production of hydrogen sulphide by sulphate reducing bacteria in near surface sedimentary environments. Strongly negative d 34 S VCDT values of pyrite (−30 -−25 ‰) support its bacterial origin. Perfect shapes of framboids resulted from their growth in the open pore space of clastic sediments. The abundance of framboids at cer− tain sedimentary levels and the lack or negligible content of euhedral pyrite suggest pulses of high supersaturation with respect to iron monosulphides. The dominance of framboids of small sizes (8-16 μm) and their homogeneous distribution at these levels point to recurrent development of a laterally continuous anoxic sulphidic zone below the sediment surface. Sedimentary environments of the Mount Wawel Formation developed on islands of the young magmatic arc in the northern Antarctic Peninsula region. They embraced stagnant and flowing water masses and swamps located in valleys, depressions, and coastal areas that were covered by dense vegetation. Extensive deposition and diagenesis of plant detritus in these environments promoted anoxic conditions in the sediments, and a supply of marine and/or volcanogenic sulphate enabled its bacterial reduction, precipitation of iron mono− sulphides, and their transformation to pyrite framboids.

show abstract

“…The statistical method and output are detailed in the Supplementary Material along with the compiled data (http://dx. doi.org/10.6084/m9.figshare.1436115), where all compiled values are from the following sources: (Thode et al, 1951;Ford, 1957;Thode, 1957, 1958;Jones and Starkey, 1957;Kaplan and Rittenberg, 1964;Kemp and Thode, 1968;Krouse et al, 1968;McCready, 1975;McCready et al, 1975;Smock et al, 1998;Bottcher et al, 1999;Bolliger et al, 2001;Detmers et al, 2001;Farquhar et al, 2003;Kleikemper et al, 2004;Habicht et al, 2005;Johnston, 2005;Canfield, 2006;Hoek et al, 2006;Knöller et al, 2006;Johnston et al, 2007;Mangalo et al, 2007Mangalo et al, , 2008Pallud et al, 2007;Davidson et al, 2009;Sim et al, 2011aSim et al, ,b, 2012Sim et al, , 2013Leavitt et al, 2013Leavitt et al, , 2014). …”

Section: Fractionation At the Cellular Scalementioning

confidence: 99%

“…However, evidence against ApsR as the rate-limiting step is shown by studies indicating reversibility of the ApsR (Peck, 1960) and the sulfate reduction pathway Holler et al, 2011). Recent studies using oxygen isotopes as tracers have demonstrated that some intracellular sulfite is oxidized in vivo back to sulfate (Mangalo et al, 2007(Mangalo et al, , 2008Einsiedl, 2008;Farquhar et al, 2008;Turchyn et al, 2010). These studies demonstrate that sulfite re-oxidation is commonplace in MSR and often quantitatively significant (Antler et al, 2013).…”

Section: A Bmentioning

confidence: 99%

Sulfur Isotope Effects of Dissimilatory Sulfite Reductase

Leavitt

Bradley

Santos

et al. 2015

Preprint

View full text Add to dashboard Cite

The precise interpretation of environmental sulfur isotope records requires a quantitative understanding of the biochemical controls on sulfur isotope fractionation by the principle isotope-fractionating process within the S cycle, microbial sulfate reduction (MSR). Here we provide the only direct observation of the major ( 34 S/ 32 S) and minor ( 33 S/ 32 S, 36 S/ 32 S) sulfur isotope fractionations imparted by a central enzyme in the energy metabolism of sulfate reducers, dissimilatory sulfite reductase (DsrAB). Results from in vitro sulfite reduction experiments allow us to calculate the in vitro DsrAB isotope effect in 34 S/ 32 S (hereafter, 34 ε ‰ DsrAB ) to be 15.3 ± 2 , 2σ. The accompanying minor isotope effect in 33 S, described as 33 λ DsrAB , is calculated to be 0.5150 ± 0.0012, 2σ. These observations facilitate a rigorous evaluation of the isotopic fractionation associated with the dissimilatory MSR pathway, as well as of the environmental variables that govern the overall magnitude of fractionation by natural communities of sulfate reducers. The isotope effect induced by DsrAB upon sulfite reduction is a factor of 0.3-0.6 times prior indirect estimates, which have ranged from 25 to 53‰ in 34 ε DsrAB . The minor isotope fractionation observed from DsrAB is consistent with a kinetic or equilibrium effect. Our in vitro constraints on the magnitude of 34 ε DsrAB is similar to the median value of experimental observations compiled from all known published work, where 34 ε r−p = 16.1 (r-p indicates reactant vs. product, n = 648). This value closely matches those of MSR operating at high sulfate reduction rates in both laboratory chemostat experiments ( 34 ε SO4− = H2S17.3 ± 1.5 , 2σ) and in modern marine sediments ( 34 ε SO4− = H2S17.3 ± 3.8 ). Targeting the direct isotopic consequences of a specific enzymatic processes is a fundamental step toward a biochemical foundation for reinterpreting the biogeochemical and geobiological sulfur isotope records in modern and ancient environments.

show abstract

Stable isotope fractionation during bacterial sulfate reduction is controlled by reoxidation of intermediates

Cited by 76 publications

References 39 publications

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

Authigenic pyrite framboids in sedimentary facies of the Mount Wawel Formation (Eocene), King George Island, West Antarctica

Sulfur Isotope Effects of Dissimilatory Sulfite Reductase

Contact Info

Product

Resources

About