Sulphur diagenesis in the sediments of the Kiel Bight, SW Baltic Sea, as reflected by multiple stable sulphur isotopes

Abstract

In this work, the biogeochemistry of marine sediments from the Kiel Bight, coastal SW Baltic Sea, is studied based on the abundance and isotopic composition of organic carbon and different forms of sedimentary sulphur. Active bacterial sulphate reduction, partly under sulphate-limiting conditions, is evident from paired δ(34)S and δ(18)O values of pore water sulphate. The resulting pore water sulphide is partly precipitated as acid-volatile iron sulphide and subsequently forms sedimentary pyrite, partly serves in later diagenetic sulphurisation of organic matter, or remains dissolved in the pore water, all evident from the respective δ(34)S values. Microbial sulphate turnover is associated with an apparent isotopic fractionation between dissolved sulphate and dissolved sulphide (Δ(34)S) that varies between 46 and 66‰.

Multiple sulfur isotopes in methane seep carbonates track unsteady sulfur cycling during anaerobic methane oxidation

“…2a & f). Lin et al, 2017, Pellerin et al, 2015, Strauss et al, 2012, Materson et al, 2018 as well as methane seep barite (Gong et al, 2018) and sedimentary pyrite influenced by OSR and AOM-SR (Lin et al, 2018(Lin et al, , 2017. Analytical uncertainty (1s) on Δ 33 S values are shown as vertical bars.…”

Coupled C–S–Fe geochemistry in a rapidly accumulating marine sedimentary system: Diagenetic and depositional implications

“…CRS contents in this work represent the pyrite‐bound sulfur content in the sediment samples. H 2 S produced by reduction of sulfides was trapped as ZnS in zinc acetate solution (pH > 11) and subsequently reprecipitated as Ag 2 S by addition of AgNO 3 [ Canfield et al ., ; Strauss et al ., ]. δ 34 S, δ 18 O of BaSO 4 , and δ 34 S of Ag 2 S were measured with a Thermo Delta‐V‐plus isotope ratio mass spectrometer in continuous flow mode coupled with an elemental analyzer (Thermo EA‐1112).…”

“…CRS contents in this work represent the pyrite-bound sulfur content in the sediment samples. H 2 S produced by reduction of sulfides was trapped as ZnS in zinc acetate solution (pH > 11) and subsequently reprecipitated as Ag 2 S by addition of AgNO 3 [Canfield et al, 1986;Strauss et al, 2012] Total inorganic carbon (TIC) contents were determined by a carbon coulometer (UIC-CM5130). Total carbon (TC) content was measured by elemental analyzer (Thermo EA1112).…”

The Biogeochemical Sulfur Cycle of Marine Sediments

“…MSI have been measured in a variety of modern marine sediments, for example the Baltic Sea (Strauss et al, 2012), Mangrove Lake (Pellerin et al, 2015b), Alfonso Basin (Masterson et al, 2018), and South China Sea (Lin et al, 2017, 2018). In a sapropel sediment of Mangrove Lake, Bermuda, the Δ 33 S of pore water sulfate was inconsistent with only sulfate reduction.…”