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Electron Shuttles Enhance Anaerobic Ammonium Oxidation Coupled to Iron(III) Reduction
- Source :
- Environmental Science & Technology. 50:9298-9307
- Publication Year :
- 2016
- Publisher :
- American Chemical Society (ACS), 2016.
-
Abstract
- Anaerobic ammonium oxidation coupled to iron(III) reduction, termed Feammox, is a newly discovered nitrogen cycling process. However, little is known about the roles of electron shuttles in the Feammox reactions. In this study, two forms of Fe(III) (oxyhydr)oxide ferrihydrite (ex situ ferrihydrite and in situ ferrihydrite) were used in dissimilatory Fe(III) reduction (DIR) enrichments from paddy soil. Evidence for Feammox in DIR enrichments was demonstrated using the (15)N-isotope tracing technique. The extent and rate of both the (30)N2-(29)N2 and Fe(II) formation were enhanced when amended with electron shuttles (either 9,10-anthraquinone-2,6-disulfonate (AQDS) or biochar) and further simulated when these two shuttling compounds were combined. Although the Feammox-associated Fe(III) reduction accounted for only a minor proportion of total Fe(II) formation compared to DIR, it was estimated that the potentially Feammox-mediated N loss (0.13-0.48 mg N L(-1) day(-1)) was increased by 17-340% in the enrichments by the addition of electron shuttles. The addition of electron shuttles led to an increase in the abundance of unclassified Pelobacteraceae, Desulfovibrio, and denitrifiers but a decrease in Geobacter. Overall, we demonstrated a stimulatory effect of electron shuttles on Feammox that led to higher N loss, suggesting that electron shuttles might play a crucial role in Feammox-mediated N loss from soils.
- Subjects :
- 0301 basic medicine
In situ
Iron
Inorganic chemistry
Oxide
chemistry.chemical_element
Electrons
General Chemistry
010501 environmental sciences
Ferric Compounds
01 natural sciences
Nitrogen
03 medical and health sciences
Denitrifying bacteria
chemistry.chemical_compound
Ferrihydrite
Electron transfer
030104 developmental biology
chemistry
Ammonium Compounds
Biochar
Environmental Chemistry
Ammonium
Oxidation-Reduction
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 15205851 and 0013936X
- Volume :
- 50
- Database :
- OpenAIRE
- Journal :
- Environmental Science & Technology
- Accession number :
- edsair.doi.dedup.....558e6252a9ef04d26480e8fc5d80986a