Unraveling the role of sulfide-natural organic matter interplay on methane cycling in anoxic environments
Por:
Valenzuela, I, Edgardo, Bryce, Casey, Forberg, Judith, Planer-Friedrich, Britta, Kappler, Andreas, Cervantes, Francisco J.
Publicada:
1 nov 2022
Resumen:
Redox-active natural organic matter (NOM) possesses great potential to
fuel chemical and biological reactions due to its electron-transferring
capacity. Chemical sulfide oxidation with redox-active NOM as the
terminal electron acceptor (TEA) has been shown to determine the extent
to which organic matter degradation produces CO2 or CH4 by suppressing
methanogenesis. However, the effect that such S cycling reactions
potentially have on CH4-consuming processes, such as sulfate- and
NOM-dependent anaerobic oxidation of methane (AOM), is yet to be
disclosed. In this study, bulk Pahokee Peat humic substances (PPHS) were
employed as a model source of redox-active NOM to test their role as TEA
for the chemical oxidation of dissolved sulfide. While elemental sulfur
was the dominant product of sulfide oxidation (similar to 50 to 75% of
oxidized sulfur), thiosulfate was the second most abundant product
accounting for similar to 20% of the oxidized sulfide. The
incorporation of S into PPHS' organic structure was revealed by the
formation of methylthio, ethylthio, thiol, and
aromatic-disulfide/polysulfide moieties after the reaction, which may
compromise the availability of NOM to act as TEA for the oxidation of
organic matter or methane. Wetland sediment incubations amended with
sulfate and PPHS revealed that PPHS were the preferential TEA for
catalyzing AOM (NOM-AOM) while sulfate suppressed methanogenic
activities. Considering this and several novel findings concerning
sulfate- and NOM-driven AOM, we discuss novel mechanisms by which
sulfur/organic matter interactions could impact the microbial processes
of CH4 production and consumption.
Filiaciones:
Bryce, Casey:
Univ Bristol, Sch Earth Sci, Bristol, Avon, England
Forberg, Judith:
Univ Bayreuth, Bayreuth Ctr Ecol & Environm Res BayCEER, Environm Geochem, D-95447 Bayreuth, Germany
Planer-Friedrich, Britta:
Univ Bayreuth, Bayreuth Ctr Ecol & Environm Res BayCEER, Environm Geochem, D-95447 Bayreuth, Germany
Kappler, Andreas:
Univ Tubingen, Dept Appl Geosci, Geomicrobiol, Tubingen, Germany
Cervantes, Francisco J.:
Valenzuela, Edgardo, I , Univ Nacl Autonoma Mexico, Engn Inst, Lab Res Adv Proc Water Treatment, Campus Juriquilla,Blvd Juriquilla 2001, Queretaro 76230, Mexico
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