Sulphur isotope fractionation in modern microbial mats and the evolution of the sulphur cycle

Nature ◽  
1996 ◽  
Vol 382 (6589) ◽  
pp. 342-343 ◽  
Author(s):  
Kirsten S. Habicht ◽  
Donald E. Canfield
Keyword(s):  
Isotope Fractionation ◽  
Microbial Mats ◽  
Sulphur Isotope ◽  
Sulphur Cycle

Heterogeneity in the Ediacaran–Cambrian coastal oceans: a sulphur isotope perspective

2019 ◽  
Vol 157 (7) ◽  
pp. 1112-1120
Author(s):  
Ying Lin ◽  
Nanping Wu ◽  
Da Li ◽  
Hong-Fei Ling
Keyword(s):  
Global Scale ◽  
Continental Margins ◽  
Early Cambrian ◽  
Sulphur Isotope ◽  
Coastal Oceans ◽  
First Order ◽  
Sulphur Cycle ◽  
Sulphur Cycling ◽  
Cas A ◽  
Depositional Setting

AbstractMultiple sulphur isotope compositions of sedimentary pyrites across the Ediacaran–Cambrian (Ed–C) transition and into the early Cambrian from the Xiaotan section, Yunnan, South China, are presented to explore the evolution of the sulphur cycle. The values of δ34Spy range from 13.5 ‰ to 35.8 ‰, and the values of Δ33Spy range from −0.044 ‰ to 0.063 ‰. The first-order observation of highly positive δ34Spy is consistent with sulphur isotope records from other sedimentary successions (with various degrees of enrichment in 34S), reflecting a common feature in cycling of sulphur among ocean basins. The positive values suggest that pyrite was formed in a depositional setting with limiting availability of sulphate that suppressed the expression of microbial fractionations. The first-order observation of a 10-million-year period of negative Δ33Spy beginning around the Ed–C boundary likely reflects changes in isotopic compositions of sulphur influx to the oceans. Such changes are suggested to be linked to a pulse of preferred weathering of sulphides (with negative Δ33S) relative to sulphate, which may reflect enhanced exposure of pyrites in continental margins due to reorganization of continents at this time. Both δ34Spy and Δ33Spy data imply low seawater sulphate levels, and possibly heterogeneity in sulphate concentrations in the world’s coastal oceans. The predictions about sulphur isotope signatures of evolved seawater (with highly positive δ34S and negative Δ33S) at the Xiaotan section are testable with future measurements of carbonate-associated sulphate (CAS), a proxy of ancient oceanic sulphate that carries information about the operation of sulphur cycling on a global scale.

Sulphur isotope fractionation during transformation of AVS to pyrite

1998 ◽  
Vol 43 (S1) ◽  
pp. 35-35
Author(s):  
W. M. Duan ◽  
K. Pye ◽  
M. Coleman
Keyword(s):  
Isotope Fractionation ◽  
Sulphur Isotope

scholarly journals Trimethylamine and Organic Matter Additions Reverse Substrate Limitation Effects on the δ13C Values of Methane Produced in Hypersaline Microbial Mats

2014 ◽  
Vol 80 (23) ◽  
pp. 7316-7323 ◽  
Author(s):  
Cheryl A. Kelley ◽  
Brooke E. Nicholson ◽  
Claire S. Beaudoin ◽  
Angela M. Detweiler ◽  
Brad M. Bebout
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Natural Organic Matter ◽  
Methane Production ◽  
Isotope Fractionation ◽  
Microbial Mats ◽  
Hypersaline Environments ◽  
Substrate Limitation ◽  
Main Substrate ◽  
Isotope Measurements

ABSTRACTMethane production has been observed in a number of hypersaline environments, and it is generally thought that this methane is produced through the use of noncompetitive substrates, such as the methylamines, dimethylsulfide and methanol. Stable isotope measurements of the produced methane have also suggested that the methanogens are operating under conditions of substrate limitation. Here, substrate limitation in gypsum-hosted endoevaporite and soft-mat hypersaline environments was investigated by the addition of trimethylamine, a noncompetitive substrate for methanogenesis, and dried microbial mat, a source of natural organic matter. The δ13C values of the methane produced after amendments were compared to those in unamended control vials. At all hypersaline sites investigated, the δ13C values of the methane produced in the amended vials were statistically lower (by 10 to 71‰) than the unamended controls, supporting the hypothesis of substrate limitation at these sites. When substrates were added to the incubation vials, the methanogens within the vials fractionated carbon isotopes to a greater degree, resulting in the production of more13C-depleted methane. Trimethylamine-amended samples produced lower methane δ13C values than the mat-amended samples. This difference in the δ13C values between the two types of amendments could be due to differences in isotope fractionation associated with the dominant methane production pathway (or substrate used) within the vials, with trimethylamine being the main substrate used in the trimethylamine-amended vials. It is hypothesized that increased natural organic matter in the mat-amended vials would increase fermentation rates, leading to higher H2concentrations and increased CO2/H2methanogenesis.

Diagenetic pyrite formation and sulphur isotope fractionation associated with a Westphalian marine incursion, northern England

1983 ◽  
Vol 74 (3) ◽  
pp. 165-182 ◽  
Author(s):  
L. G. Love ◽  
M. L. Coleman ◽  
C. D. Curtis
Keyword(s):  
Fresh Water ◽  
Isotope Fractionation ◽  
Sediment Deposition ◽  
Sulphur Isotope ◽  
Isotope Data ◽  
Pyrite Formation ◽  
Relationship Of ◽  
Coal Measures ◽  
The Relationship ◽  
S Isotope

ABSTRACTPyrite textures are described and illustrated and stable S-isotope data are presented from the Alton (Gastrioceras listen) marine horizon of the Westphalian Lower Coal Measures, from sections near Penistone in central northern England, with the object of relating the paragenetic sequence of pyrite formation to the conditions of sediment deposition and diagenesis. The earliest diagenetic pyrite is dispersed as framboidal and related textures. It is followed in the marine shale, coal and ganister by more localised but more intense pyrite deposition and replacement in a variety of textures. Most of this is precompactional in age, but some, together with pyrite in veinlets and cleat, is postcompactional. Marcasite is rare and mainly late. δ34S ratios range between −35·31‰ and +20·39‰. There is a definite trend from lighter values (−1·15 ± 6·47‰) in the marine part of the sequence to much heavier values (+12·73 ± 7·66‰) in the sediment below the coal. This allows the relationship of the earliest pyrite deposition in the coal-peat and ganister to the chemistry of their own depositional fresh water to be seen but then relates the main pyrite deposition to the influx of the marine-water sulphate of the Alton horizon, and shows the penetration of this influence downward into the coal-peat and its seat-bed.

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