Distribution and isotopic composition of trimethylamine, dimethylsulfide and dimethylsulfoniopropionate in marine sediments of Aarhus Bay, supplement to: Zhuang, Guang-Chao; Lin, Yu-Shih; Bowles, Marshall W; Heuer, Verena B; Lever, Mark A; Elvert, Marcus; Hinrichs, Kai-Uwe (2017): Distribution and isotopic composition of trimethylamine, dimethylsulfide and dimethylsulfoniopropionate in marine sediments. Marine Chemistry, 196, 35-46

DOI

Methylated amines and sulfides are ubiquitous organic nitrogen and sulfur compounds in the marine environment and could serve as important energy substrates to methanogens inhabiting anoxic sediments. However, their abundance and isotopic values remain largely unconstrained in marine sediments. In this study, we investigated the distribution of trimethylamine (TMA), dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in Aarhus Bay, Denmark and provided the first report for their stable carbon isotopic composition. Simultaneous measurement of those two compounds in small volumes of pore waters and sediments was accomplished with gas chromatography in combination with either a purge and trap system for quantification or a headspace method for carbon isotopic analysis. TMA in the solid phase (exchangeable pool, 0.3-6.6 µmol/kg wet sediment; base-extractable pool, 2-18 µmol/kg) was much more abundant than the dissolved pool (< 20 nM), indicating strong adsorption of TMA to sediments. Likewise, total base-hydrolyzable DMS(P)t (including DMS and base-released DMS from DMSP) in sediment was at least three orders of magnitude higher (11-65 µmol/kg) than the dissolved pool of DMS(P)d in the pore water (including DMS and dissolved DMSP; 1-12 nM). TMA and DMS(P) contents in the solid phase peaked in the surface sediment, consistent with their phytodetrital origin. TMA was more 13C-depleted than DMS(P) (TMA: -36.4 per mil to -39.2 per mil; DMS: -18.6 per mil to -23.4 per mil), presumably due to different biological or biosynthetic origins of the respective methyl groups. Both compounds showed a downcore decrease in their solid-phase concentration, a feature that was attributed to microbial degradation, but progressive enrichment in 13C (up to 4 per mil) with depth was observed only for DMS(P). The considerable pool size of TMA and DMS(P) outlined in this study and geochemical evidence of their degradability suggested these two compounds could be potentially important substrates for methane production in sulfate-reducing environments.

Identifier
DOI https://doi.org/10.1594/PANGAEA.888371
Related Identifier https://doi.org/10.1016/j.marchem.2017.07.007
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.888371
Provenance
Creator Zhuang, Guang-Chao; Lin, Yu-Shih; Bowles, Marshall W; Heuer, Verena B; Lever, Mark A; Elvert, Marcus; Hinrichs, Kai-Uwe
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2018
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Representation
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Size 2 datasets
Discipline Earth System Research
Spatial Coverage (10.347W, 56.103S, 10.458E, 56.118N)