Investigating pathways of diagenetic organic matter sulfurization using compound-specific sulfur isotope analysis

Werne, Josef P.; Lyons, Timothy W.; Hollander, David J.; Schouten, Stefan; Hopmans, Ellen C.; Damsté, Jaap S. Sinninghe

doi:10.1016/j.gca.2008.04.033

Cited by 96 publications

(56 citation statements)

References 108 publications

(150 reference statements)

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“…at m/z 380. HBI thiolanes have been observed in Cariaco Basin sediments (Werne et al, 2000) and were isolated for conventional sulfurisotopic analysis (Werne et al, 2008). Similar to the C 20 isoprenoid thiophenes, identical HBI thiolanes were observed in both the apolar (F1) and polar (F3) fractions, with a higher abundance in F3 (5 to 63 nmol/g OC) than in F1 (2 to 18 nmol/g OC).…”

Section: Osc Identification and Abundancementioning

confidence: 79%

“…As these results apply to the same compounds, both cannot be correct. Given the improved specificity of our GC-ICPMS technique, the LC-EA-IRMS results probably described a mixture of the target OSC and some other coeluting (on LC) or background sulfur species, though there was no indication of additional compounds in the fraction when analyzed with GC-FPD (Werne et al, 2008). Nevertheless, the presence of a sulfur blank in the isolated fractions could potentially explain the high δ 34 S values for OSCs in Werne et al (2008), as these sulfur isotope compositions were determined via EA-IRMS.…”

Section: Variety Of Cleanup and Fractionation Schemes And Different Imentioning

confidence: 99%

“…2A. The sulfur isotopic compositions of HBI thiolanes in F1 and the triterpenoid thiane were measured in a previous study of Cariaco Basin sediment extracts by Werne et al (2008). Using preparative liquid chromatography (LC) followed by EA-IRMS, they obtained δ 34 S values between -21‰ and -5‰ for depths between 240 and 580 cm, an enrichment of ca.…”

Section: Variety Of Cleanup and Fractionation Schemes And Different Imentioning

confidence: 99%

“…The phenomenon has been difficult to explain on the basis of experimental (Amrani and Aizenshtat, 2004) and initial compound-specific δ 34 S results (Werne et al, 2008). Moreover, only a subset of available functionalized organic compounds are affected by sulfurization, while others persist in sediments without experiencing sulfurization.…”

Section: Introductionmentioning

confidence: 99%

“…The sulfur isotopic composition of bulk pools has been used to constrain the timing of kerogen and extractable OSC formation relative to pyrite and other sedimentary sulfur sinks. However, because OSCs form at different rates and during various stages of early diagenesis ( Vairavamurthy and Mopper, 1987;Vairavamurthy et al, 1994;Sinninghe Damsté et al, 2007;Werne et al, 2008), bulk OS potentially represents a mixture of OSCs with diverse δ 34 S values.…”

Section: Introductionmentioning

confidence: 99%

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Sulfur isotopic composition of individual organic compounds from Cariaco Basin sediments

Raven

Adkins

Werne

et al. 2015

Organic Geochemistry

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Reactions between reduced inorganic sulfur and organic compounds are thought to be important for the preservation of organic matter (OM) in sediments, but the sulfurization process is poorly understood. Sulfur isotopes are potentially useful tracers of sulfurization reactions, which often occur in the presence of a strong porewater isotopic gradient driven by microbial sulfate reduction. Prior studies of bulk sedimentary OM indicate that sulfurized products are 34 Senriched relative to coexisting sulfide, and experiments have produced 34 S-enriched organosulfur compounds. However, analytical limitations have prevented the relationship from being tested at the molecular level in natural environments. Here we apply a new method, coupled gas chromatography -inductively coupled plasma mass spectrometry, to measure the compoundspecific sulfur isotopic compositions of volatile organosulfur compounds over a 6 m core of anoxic Cariaco Basin sediments. In contrast to current conceptual models, nearly all extractable organosulfur compounds were substantially depleted in 34 S relative to coexisting kerogen and 2 porewater sulfide. We hypothesize that this 34 S depletion is due to a normal kinetic isotope effect during the initial formation of a carbon-sulfur bond and that the source of sulfur in this relatively irreversible reaction is most likely the bisulfide anion in sedimentary pore water. The 34 Sdepleted products of irreversible bisulfide addition alone cannot explain the isotopic composition of total extractable or residual OM. Therefore, at least two different sulfurization pathways must operate in the Cariaco Basin, generating isotopically distinct products. Compound-specific sulfur isotope analysis thus provides new insights into the timescales and mechanisms of OM sulfurization.3

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Section: Osc Identification and Abundancementioning

confidence: 79%

Section: Variety Of Cleanup and Fractionation Schemes And Different Imentioning

confidence: 99%

Section: Variety Of Cleanup and Fractionation Schemes And Different Imentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%