Source of the oxygen atoms of nitrate in the oxidation of nitrite by Nitrobacter agilis and evidence against a PON anhydride mechanism in oxidative phosphorylation

Hollocher, Thomas C.

doi:10.1016/0003-9861(84)90499-5

Cited by 164 publications

(96 citation statements)

References 18 publications

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“…2) (32,33). During ammonification of soil organic matter followed by nitrification, three new atoms of oxygen are incorporated into the newly formed nitrate molecule, two of which are derived from water resulting in low δ…”

Section: Resultsmentioning

confidence: 99%

Long-term fate of nitrate fertilizer in agricultural soils

Sébilo

Mayer

Nicolardot

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

566

308

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Increasing diffuse nitrate loading of surface waters and groundwater has emerged as a major problem in many agricultural areas of the world, resulting in contamination of drinking water resources in aquifers as well as eutrophication of freshwaters and coastal marine ecosystems. Although empirical correlations between application rates of N fertilizers to agricultural soils and nitrate contamination of adjacent hydrological systems have been demonstrated, the transit times of fertilizer N in the pedosphere-hydrosphere system are poorly understood. We investigated the fate of isotopically labeled nitrogen fertilizers in a three-decade-long in situ tracer experiment that quantified not only fertilizer N uptake by plants and retention in soils, but also determined to which extent and over which time periods fertilizer N stored in soil organic matter is rereleased for either uptake in crops or export into the hydrosphere. We found that 61-65% of the applied fertilizers N were taken up by plants, whereas 12-15% of the labeled fertilizer N were still residing in the soil organic matter more than a quarter century after tracer application. Between 8-12% of the applied fertilizer had leaked toward the hydrosphere during the 30-y observation period. We predict that additional exports of 15 N-labeled nitrate from the tracer application in 1982 toward the hydrosphere will continue for at least another five decades. Therefore, attempts to reduce agricultural nitrate contamination of aquatic systems must consider the long-term legacy of past applications of synthetic fertilizers in agricultural systems and the nitrogen retention capacity of agricultural soils.nitrogen cycle | nitrate leaching | isotopic biogeochemistry

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Section: Resultsmentioning

confidence: 99%

Long-term fate of nitrate fertilizer in agricultural soils

Sébilo

Mayer

Nicolardot

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

566

308

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“…4-7) emanating from the Sacramento-San Joaquin Delta region deserve some attention, as the origin of the d 18 O NO 3 in marine systems is the subject of some recent debate (Casciotti et al 2002). Earlier studies showed that the oxygen atoms of NO 2 3 formed during the process of nitrification originate from both water and dissolved oxygen (Hollocher et al 1981;Andersson and Hooper 1983;Hollocher 1984 (Quay et al 1995;Brandes and Devol 1997). Thus, the contribution of dissolved O 2 atoms to NO 2 3 isotopic composition should be +24% or higher.…”

Section: Northern Sf Baymentioning

confidence: 99%

“…There is currently some uncertainty surrounding the controls of the oxygen isotopic composition of nitrate (d 18 O NO 3 ). Although several decades of freshwater research has shown that NO 2 3 oxygen originates both from dissolved oxygen (O 2 ) and from water during nitrification (Hollocher et al 1981;Andersson and Hooper 1983;Hollocher 1984), recent evidence has implied that the process of nitrification in an open-water marine environment incorporates oxygen atoms almost entirely from water (Casciotti et al 2002). Hence, the factors determining the d 18 O signature of NO 2 3 may actually vary between freshwater and marine systems and may be even more complex in an estuary.…”

mentioning

confidence: 99%

Nitrogen sources and cycling in the San Francisco Bay Estuary: A nitrate dual isotopic composition approach

Wankel

Kendall

Francis

et al. 2006

Limnology & Oceanography

131

114

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We used the dual isotopic composition of nitrate (d 15 N and d 18 O) within the estuarine system of San Francisco (SF) Bay, California, to explore the utility of this approach for tracing sources and cycling of nitrate (NO 2 3 ). Surface water samples from 49 sites within the estuary were sampled during July-August 2004. Spatial variability in the isotopic composition suggests that there are multiple sources of nitrate to the bay ecosystem including seawater, several rivers and creeks, and sewage effluent. The spatial distribution of nitrate from these sources is heavily modulated by the hydrodynamics of the estuary. Mixing along the estuarine salinity gradient is the main control on the spatial variations in isotopic composition of nitrate within the northern arm of SF Bay. However, the nitrate isotopic composition in the southern arm of SF Bay exhibited a combination of source mixing and phytoplankton drawdown due mostly to the long residence time during the summer study period.

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“…O values reportedly produced by nitrification in freshwater lakes and aquifers span a contended range of 30‰, from −15‰ to 15‰ (2,25), attributed to the origin of the oxygen atoms appended to NH 3 during the two-step process of nitrification: the biological oxidation of NH 3 to NO 2 − incorporates one oxygen atom from molecular O 2 and one from water (7,26,27); the subsequent oxidation of NO 2 − to NO 3 − incorporates an O atom derived from water (28). Recent work, however, has revealed kinetic isotope effects associated with enzymatic incorporation of each of the three O atoms into the product NO 3 − (5, 6), as well an inverse kinetic isotope effect on the reactant NO 2 − during oxidation to NO 3 − (4) and the isotopic equilibration of O atoms between NO 2 − and water (29,30).…”

mentioning

confidence: 99%