Iron oxides impact sulfate-driven anaerobic oxidation of methane in diffusion-dominated marine sediments

Microbial iron (Fe) reduction by naturally abundant minerals has been observed in many anoxic aquatic sediments the sulfidic and methanic zones, deeper than it is expected based on its energetic yield. However, potential consequence of this “deep” microbial elemental cycles still unclear where diffusion dominant transport process. In contribution, we experimentally quantify impact oxides sulfate-driven anaerobic oxidation methane (S-AOM) within sulfate transition zone (SMTZ) marine diffusive controlled sediments. Sediments were collected from oligotrophic Southeastern (SE) Mediterranean continental shelf incubated with 13 C-labeled methane. We followed conversion as a proxy S-AOM monitored sediment response to hematite addition. Our study shows significant process SMTZ, which appears be co-occurring S-AOM. Based combined evidence sulfur carbon isotopes functional gene analysis, seems slow down This contrasts seep environments, appear stimulate hence attenuate release greenhouse gas deep zone, addition inhibits methanogenesis production. The inhibition effect not related Fe-AOM competing substrate, since was throughout several additions.