Dissimilatory reduction of nitrate to ammonium, not denitrification or anammox, dominates benthic nitrate reduction in tropical estuaries

Dong, Lixin; Sobey, Milika Naqasima; Smith, Cindy J.; Rusmana, Iman; Phillips, Wayne; Stott, Andrew; Osborn, A. Mark; Nedwell, David B.

doi:10.4319/lo.2011.56.1.0279

Cited by 212 publications

(142 citation statements)

References 61 publications

(66 reference statements)

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“…Higher water temperatures also enhance bacterial activity, and denitrification and nitrification, which both produce N 2 O, are known to be enhanced when temperature increases (Saad and Conrad, 1993;Van Hulle et al, 2010;Dong et al, 2011). High N 2 O concentrations were observed in summer and spring.…”

Section: Discussionmentioning

confidence: 93%

Emission and oxidation of methane in a meromictic, eutrophic and temperate lake (Dendre, Belgium)

et al. 2017

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h i g h l i g h t sThe studied lake was meromictic and characterized by high methane, nutrients and sulfate concentrations in the water column. High aerobic and anaerobic methane oxidation rates were observed in the water column, and were dependent on the season. Anaerobic methane oxidation was linked to sulfate reduction, and potentially to nitrate reduction. Despite high methane oxidation rates, methane fluxes to the atmosphere were high. a r t i c l e i n f o a b s t r a c tWe sampled the water column of the Dendre stone pit lake (Belgium) in spring, summer, autumn and winter. Depth profiles of several physico-chemical variables, nutrients, dissolved gases (CO 2 , CH 4 , N 2 O), sulfate, sulfide, iron and manganese concentrations and d 13 C-CH4 were determined. We performed incubation experiments to quantify CH 4 oxidation rates, with a focus on anaerobic CH 4 oxidation (AOM), without and with an inhibitor of sulfate reduction (molybdate). The evolution of nitrate and sulfate concentrations during the incubations was monitored. The water column was anoxic below 20 m throughout the year, and was thermally stratified in summer and autumn. High partial pressure of CO 2 and CH 4 and high concentrations of ammonium and phosphate were observed in anoxic waters. Important nitrous oxide and nitrate concentration maxima were also observed (up to 440 nmol L À1 and 80 mmol L À1 , respectively). Vertical profiles of d 13 C-CH 4 unambiguously showed the occurrence of AOM. Important AOM rates (up to 14 mmol L À1 d À1 ) were observed and often co-occurred with nitrate consumption peaks, suggesting the occurrence of AOM coupled with nitrate reduction. AOM coupled with sulfate reduction also occurred, since AOM rates tended to be lower when molybdate was added. CH 4 oxidation was mostly aerobic (~80% of total oxidation) in spring and winter, and almost exclusively anaerobic in summer and autumn. Despite important CH 4 oxidation rates, the estimated CH 4 fluxes from the water surface to the atmosphere were high (mean of 732 mmol m À2 d À1 in spring, summer and autumn, and up to 12,482 mmol m À2 d À1 in winter).

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Section: Discussionmentioning

confidence: 93%

Emission and oxidation of methane in a meromictic, eutrophic and temperate lake (Dendre, Belgium)

et al. 2017

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“…Nonetheless, some studies illustrated that dissimilatory nitrate reduction to ammonia (DNRA) is the dominant pathway when levels of organic carbon input are high and nitrate levels are low (51,52). Organisms using DNRA can outcompete denitrification at low NO 3 Ϫ due to their greater affinity for NO 3 Ϫ ; thus, they can derive more energy from NO 3 Ϫ reduction than denitrifiers (53). However, in our incubation experiments, NO 3 Ϫ was not limiting, since the substrates were added in excess during anaerobic incubation.…”

Section: Figmentioning

confidence: 99%

Potential Contribution of Anammox to Nitrogen Loss from Paddy Soils in Southern China

Yang

Nie

et al. 2015

Appl Environ Microbiol

125

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eThe anaerobic oxidation of ammonium (anammox) process has been observed in diverse terrestrial ecosystems, while the contribution of anammox to N 2 production in paddy soils is not well documented. In this study, the anammox activity and the abundance and diversity of anammox bacteria were investigated to assess the anammox potential of 12 typical paddy soils collected in southern China. Anammox bacteria related to "Candidatus Brocadia" and "Candidatus Kuenenia" and two novel unidentified clusters were detected, with "Candidatus Brocadia" comprising 50% of the anammox population. The prevalence of the anammox was confirmed by the quantitative PCR results based on hydrazine synthase (hzsB) genes, which showed that the abundance ranged from 1.16 ؋ 10 4 to 9.65 ؋ 10 4 copies per gram of dry weight. The anammox rates measured by the isotope-pairing technique ranged from 0.27 to 5.25 nmol N per gram of soil per hour in these paddy soils, which contributed 0.6 to 15% to soil N 2 production. It is estimated that a total loss of 2.50 ؋ 10 6 Mg N per year is linked to anammox in the paddy fields in southern China, which implied that ca. 10% of the applied ammonia fertilizers is lost via the anammox process. Anammox activity was significantly correlated with the abundance of hzsB genes, soil nitrate concentration, and C/N ratio. Additionally, ammonia concentration and pH were found to be significantly correlated with the anammox bacterial structure.

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“…Studies that link seasonally 63 changing temperatures to DNRA and denitrification rates suggest that warming may influence 64 the balance of N cycling (Jørgensen 1989 Higher temperatures may increase sediment O 2 consumption and thus be linked to lowersediment redox potentials that favor DNRA (Giblin et al 2013). Furthermore, DNRA has been 67 found to be dominant in warmer tropical ecosystems, and negligible in cold, deep sediments 68 (Dong et al 2011;Crowe et al 2012). If warming sediments have a similar effect as seasonally 69 or spatially changing temperatures, climate change could increase the relative importance of 70 DNRA to NO 3 -reduction.…”

Section: Introduction 44mentioning

confidence: 99%

Effects of experimental warming and carbon addition on nitrate reduction and respiration in coastal sediments

2015

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higher effects of C addition compared to warming. Combined warming and C addition had the 30 strongest effect on nitrate flux across the sediment water interface, with a complete switch early 31 in the experiment from influx to sustained efflux. Supporting this result, vial incubations with 32 added 15 N-nitrate indicated that C addition stimulated potential rates of dissimilatory nitrate 33 reduction to ammonium (DNRA), but not denitrification. Overall capacity for both 34 denitrification and DNRA was reduced in warmed treatments, possibly reflecting C losses due to 35 increased respiration with warming. Anammox potential rates were much lower than DNRA or 36 denitrification, and were slightly negatively affected by warming or C addition. Overall, results 37 indicate that warming and C addition increased ammonium production through remineralization 38 and possibly DNRA. This stimulated nitrate production through nitrification, but without a 39 comparable increase in nitrate consumption through denitrification. The response to C of 40 potential DNRA rates over denitrification, along with a switch to nitrate efflux, raises the 41 possibility that DNRA is an important and previously overlooked source of internal N cycling in 42 shelf sediments. 43Nitrate reduction in coastal sediments 3 Introduction 44

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Dissimilatory reduction of nitrate to ammonium, not denitrification or anammox, dominates benthic nitrate reduction in tropical estuaries

Cited by 212 publications

References 61 publications

Emission and oxidation of methane in a meromictic, eutrophic and temperate lake (Dendre, Belgium)

Emission and oxidation of methane in a meromictic, eutrophic and temperate lake (Dendre, Belgium)

Potential Contribution of Anammox to Nitrogen Loss from Paddy Soils in Southern China

Effects of experimental warming and carbon addition on nitrate reduction and respiration in coastal sediments

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