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Organic matter from redoximorphic soils accelerates and sustains microbial Fe(III) reduction.
Environ. Sci. Technol. 55, 10821-10831 (2021)
Microbial reduction of Fe(III) minerals is a prominent process in redoximorphic soils and is strongly affected by organic matter (OM). We herein determined the rate and extent of microbial reduction of ferrihydrite (Fh) with either adsorbed or coprecipitated OM by Geobacter sulfurreducens. We focused on OM-mediated effects on electron uptake and alterations in Fh crystallinity. The OM was obtained from anoxic soil columns (effluent OM, efOM) and included-unlike water-extractable OM-compounds released by microbial activity under anoxic conditions. We found that organic molecules in efOM had generally no or only very low electron-accepting capacity and were incorporated into the Fh aggregates when coprecipitated with Fh. Compared to OM-free Fh, adsorption of efOM to Fh decelerated the microbial Fe(III) reduction by passivating the Fh surface toward electron uptake. In contrast, coprecipitation of Fh with efOM accelerated the microbial reduction, likely because efOM disrupted the Fh structure, as noted by Mössbauer spectroscopy. Additionally, the adsorbed and coprecipitated efOM resulted in a more sustained Fe(III) reduction, potentially because efOM could have effectively scavenged biogenic Fe(II) and prevented the passivation of the Fh surface by the adsorbed Fe(II). Fe(III)-OM coprecipitates forming at anoxic-oxic interfaces are thus likely readily reducible by Fe(III)-reducing bacteria in redoximorphic soils.
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Anmerkungen
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Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Schlagwörter
Dom ; Mössbauer Spectroscopy ; Dissolved Organic Matter ; Electron-accepting Capacity ; Ferrihydrite ; Iron Oxide ; Mediated Electrochemical Reduction; Humic Substances; Iron(iii) Oxyhydroxides; Mossbauer-spectroscopy; Electron-acceptors; Ferrous Iron; Ferrihydrite; Oxide; Carbon; Reactivity; Exopolysaccharides
Sprache
englisch
Veröffentlichungsjahr
2021
HGF-Berichtsjahr
2021
ISSN (print) / ISBN
0013-936X
e-ISSN
1520-5851
Zeitschrift
Environmental Science & Technology
Quellenangaben
Band: 55,
Heft: 15,
Seiten: 10821-10831
Verlag
ACS
Verlagsort
Washington, DC
Begutachtungsstatus
Peer reviewed
Institut(e)
Institute of Groundwater Ecology (IGOE)
POF Topic(s)
20403 - Sustainable Water Management
Forschungsfeld(er)
Environmental Sciences
PSP-Element(e)
G-504300-004
WOS ID
WOS:000683363600060
Scopus ID
85112361905
PubMed ID
34288663
Erfassungsdatum
2021-09-13