caa a22 4500 605517266 CHVBK 20210128100718.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s10533-014-0052-5 doi (NATIONALLICENCE)springer-10.1007/s10533-014-0052-5 Solid phases as important electron acceptors in freshwater organic sediments [Elektronische Daten] [Maximilian Lau, Michael Sander, Jörg Gelbrecht, Michael Hupfer] Ferric iron in particulate iron (oxyhydr-) oxides and quinone moieties in dissolved organic matter (DOM) are well-established terminal electron acceptors (TEA) in heterotrophic anaerobic microbial respiration. The importance of particulate organic matter (POM) as TEA is, however, much less studied and understood despite the fact that POM is more abundant than DOM in many soils and sediments. Here, we studied the microbial reduction of POM and Fe(III)-containing phases in freshwater sediments. We present an electrochemical approach that can be used to assess the combined contributions of POM and Fe(III) to the TEA pools of soils and sediments. Following oxidation and drying of sediments from two carbonate-buffered freshwater lakes in air, wetting re-initiated anaerobic microbial respiration in thesediment samples as evidenced from electron transfer to solid-phase electron acceptors over three weeks of anoxic incubations. The microbial reduction of POM and mineral-associated ferric iron was directly quantified by mediated electrochemical analysis. We estimate that the POM from the analyzed sediments provided a capacity to accept or donate electrons of about 650µmol e− (g organic carbon)−1. Our work substantiates earlier studies that suggested that the reduction of redox-active moieties in POM is an important contributor to anaerobic microbial respiration and might be responsible for the competitive suppression of methanogenesis in organicmatter rich wetland soils. Our results further indicate that microbial reduction of POM must be accounted for to close respiration balances in (temporary) anoxic freshwater systems and peatlands. Springer International Publishing Switzerland, 2014 Particulate organic matter nationallicence Electron acceptor nationallicence Anaerobic respiration nationallicence Electrochemistry nationallicence Lau Maximilian Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany aut Sander Michael Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland aut Gelbrecht Jörg Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany aut Hupfer Michael Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany aut Biogeochemistry Springer International Publishing 123/1-2(2015-03-01), 49-61 0168-2563 123:1-2<49 2015 123 10533 https://doi.org/10.1007/s10533-014-0052-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-014-0052-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lau Maximilian Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany aut NATIONALLICENCE 700 1- Sander Michael Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland aut NATIONALLICENCE 700 1- Gelbrecht Jörg Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany aut NATIONALLICENCE 700 1- Hupfer Michael Department of Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 123/1-2(2015-03-01), 49-61 0168-2563 123:1-2<49 2015 123 10533