|Appears in Collections:||Biological and Environmental Sciences Journal Articles|
|Peer Review Status:||Refereed|
|Title:||Organic matter from redoximorphic soils accelerates and sustains microbial Fe(III) reduction|
Byrne, James M
Meckenstock, Rainer U
Totsche, Kai U
mediated electrochemical reduction
dissolved organic matter
|Citation:||Fritzsche A, Bosch J, Sander M, Schroeder C, Byrne JM, Ritschel T, Joshi P, Maisch M, Meckenstock RU, Kappler A & Totsche KU (2021) Organic matter from redoximorphic soils accelerates and sustains microbial Fe(III) reduction. Environmental Science and Technology, 55 (15), pp. 10821-10831. https://doi.org/10.1021/acs.est.1c01183|
|Abstract:||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 towards 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, adsorbed and co-precipitated 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 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.|
|Rights:||This item has been embargoed for a period. During the embargo please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science and Technology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.est.1c01183|
|es-2021-01183k-R2_SI.pdf||Supporting Information||1.49 MB||Adobe PDF||Under Embargo until 2022-07-22 Request a copy|
|es-2021-01183k.R3_Proof_hi.pdf||Fulltext - Accepted Version||912.61 kB||Adobe PDF||Under Embargo until 2022-07-22 Request a copy|
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