Nitrogen transformation mediated by nitrate-dependent iron oxidation in anoxic freshwater
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Fe(III) transformation to Fe(II) via the nitrate-dependent iron oxidation process, occurring in anoxic sediments, has an important role in the nitrogen cycle. In this study, laboratory experiments were performed to investigate the denitrification properties driven by nitrate-dependent iron oxidation.
Materials and methods
A 30-day incubation study of sediments and overlying water from Lake Moshui in Wuhan, China, was conducted in an anoxic condition. The nitrate reduction during the incubation was evaluated by the N2O emission and various forms of nitrogen in the overlying water. The denitrification enzyme activity and abundance of nitrate-dependent Fe(II)-oxidising bacteria were determined periodically, and their correlations with nitrogen and iron were analysed to illustrate the denitrification characteristics linked to Fe(II) oxidation in sediments.
Results and discussion
After the Fe(II) and nitrate input, the decrease of Fe(II) and nitrate concentrations was accompanied by an increase in nitrite and N2O production. The contribution of Fe(II) oxidation to the nitrate reduction accounted for 27.7% at the end of the incubation, and the rate of Fe(II) decrease was significantly correlated (P < 0.05) with the production of N2O. In addition, a positive correlation between denitrification enzyme activity and nitrate concentrations was observed. During incubation, the abundance of nitrate-dependent Fe(II)-oxidising bacteria in the sediment ranged from 1.1 × 105 cell g−1 wet sediment to 1.4 × 106 cell g−1 wet sediment, and increased with the increase of Fe(II) input concentration. The nitrate reduction coupled with Fe(II) oxidation was mainly mediated by microbial processes.
Sediment denitrification was enhanced with increasing Fe(II) concentrations, and Fe(II) may play an important role in regulating nitrogen transformation in freshwater lakes.
KeywordsDenitrification Denitrification enzyme activity Iron oxidation Nitrate-dependent Fe(II)-oxidising bacteria Sediment
This research was supported by National Key R & D Program of China (No. 2017YFC0505305).
- Pyzola S (2013) Nitrate reduction coupled to iron(II) oxidation and manganese(II) in an agricultural soil. Dissertation. University of KentuckyGoogle Scholar
- Rowe AR, Chellamuthu P, Lam B, Okamoto A, Nealson KH (2014) Marine sediments microbes capable of electrode oxidation as a surrogate for lithotrophic insoluble substrate metabolism. Front Microbiol 5:784Google Scholar
- Silva LCF, Lima HS, Sartoratto A, de Sousa MP, Torres APR, de Souza RS, de Paula SO, de Oliveira VM, da Silva CC (2018) Effect of salinity in heterotrophic nitrification/aerobic denitrification performed by acclimated microbiota from oil-produced water biological treatment system. Int Biodeterior Biodegradation 130:1–7CrossRefGoogle Scholar
- State Environmental Protection Administration of the People’s Republic of China (2002) Determination methods for examination of water and wastewater, fourth ed. China Environmental Science Press, BeijingGoogle Scholar
- Straub KL, Buchholz-Cleven BEE (1998) Enumeration and detection of anaerobic ferrous iron-oxidizing, nitrate-reducing bacteria from diverse European sediments. Appl Environ Microbiol 64:4846–4856Google Scholar
- Straub KL, Benz M, Schink B, Widdel F (1996) Anaerobic, nitrate-dependent microbial oxidation of ferrous iron. Appl Environ Microbiol 62:1458–1460Google Scholar
- Tiedje JM (1994) Denitrifiers. In: Bottomley PS, Angle JS, Weaver RW (eds) Methods of soil analysis, Part 2. Microbiological and biochemical properties. Soil Science Society of America Press, Madison, pp 253–254Google Scholar
- Zhang HH, Feng J, Chen SN, Zhao ZF, Li BQ, Wang Y, Jia JY, Li SL, Wang Y, Yan MM, Lu KY, Hao HY (2019) Geographical patterns of nirS gene abundance and nirS-type denitrifying bacterial community associated with activated sludge from different wastewater treatment plants. Microb Ecol 77:304–316CrossRefGoogle Scholar