Lin, Yu-Shih; Heuer, Verena B; Ferdelman, Timothy G; Hinrichs, Kai-Uwe (2010): Biogeochemical processes in anoxic sediment from Lake Plußsee, Germany. PANGAEA, https://doi.org/10.1594/PANGAEA.757369, Supplement to: Lin, Y-S et al. (2010): Microbial conversion of inorganic carbon to dimethyl sulfide in anoxic lake sediment (Plußsee, Germany). Biogeosciences, 7(8), 2433-2444, https://doi.org/10.5194/bg-7-2433-2010
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In anoxic environments, volatile methylated sulfides like methanethiol (MT) and dimethyl sulfide (DMS) link the pools of inorganic and organic carbon with the sulfur cycle. However, direct formation of methylated sulfides from reduction of dissolved inorganic carbon has previously not been demonstrated. When studying the effect of temperature on hydrogenotrophic microbial activity, we observed formation of DMS in anoxic sediment of Lake Plußsee at 55 °C. Subsequent experiments strongly suggested that the formation of DMS involves fixation of bicarbonate via a reductive pathway in analogy to methanogenesis and engages methylation of MT. DMS formation was enhanced by addition of bicarbonate and further increased when both bicarbonate and H2 were supplemented. Inhibition of DMS formation by 2-bromoethanesulfonate points to the involvement of methanogens. Compared to the accumulation of DMS, MT showed the opposite trend but there was no apparent 1:1 stoichiometric ratio between both compounds. Both DMS and MT had negative d13C values of -62 per mil and -55 per mil, respectively. Labeling with NaH**13CO3 showed more rapid incorporation of bicarbonate into DMS than into MT. The stable carbon isotopic evidence implies that bicarbonate was fixed via a reductive pathway of methanogenesis, and the generated methyl coenzyme M became the methyl donor for MT methylation. Neither DMS nor MT accumulation were stimulated by addition of the methyl-group donors methanol and syringic acid or by the methyl-group acceptor hydrogen sulphide. The source of MT was further investigated in a H2**35S labeling experiment, which demonstrated a microbially-mediated process of hydrogen sulfide methylation to MT that accounted for only <10% of the accumulation rates of DMS. Therefore, the major source of the 13C-depleted MT was neither bicarbonate nor methoxylated aromatic compounds. Other possibilities for isotopically depleted MT, such as other organic precursors like methionine, are discussed. This DMS-forming pathway may be relevant for anoxic environments such as hydrothermally influenced sediments and fluids and sulfate-methane transition zones in marine sediments.
Latitude: 54.166700 * Longitude: 10.383300
Date/Time Start: 2006-07-01T00:00:00 * Date/Time End: 2006-07-01T00:00:00
Datasets listed in this publication series
- Lin, Y-S; Heuer, VB; Ferdelman, TG et al. (2010): (Figure 2) Effects of H2 and bicarbonate on the formation of dimethyl sulfide, methanethiol, methane, and acetate in the sediment slurries of Lake Plußsee. https://doi.org/10.1594/PANGAEA.757299
- Lin, Y-S; Heuer, VB; Ferdelman, TG et al. (2011): (Figure 3) Concentrations and stable carbon isotopic values of dimethyl sulfide, methanethiol and methane in sediment slurries under non-labeling and labeling conditions of Lake Plußsee. https://doi.org/10.1594/PANGAEA.757335
- Lin, Y-S; Heuer, VB; Ferdelman, TG et al. (2010): (Figure 4) Distribution of radioactivity in the sediment slurries of Lake Plußsee during incubation with H2, bicarbonate and H235S. https://doi.org/10.1594/PANGAEA.757305
- Lin, Y-S; Heuer, VB; Ferdelman, TG et al. (2010): (Table 1) Concentrations of dimethyl sulfide and methanethiol after 12 days of incubation with inorganic and organic substrates of Lake Plußsee. https://doi.org/10.1594/PANGAEA.757327
- Lin, Y-S; Heuer, VB; Ferdelman, TG et al. (2010): (Table 2) Effects of 20 mmol L**-1 2-bromoethanesulfonate (BES) on formation of dimethyl sulfide, methanethiol, methane and acetate after 12 days of incubation of Lake Plußsee. https://doi.org/10.1594/PANGAEA.757332