Using isotope fractionation of nitrate-nitrogen and nitrate-oxygen for evaluation of microbial denitrification in a sandy aquifer

Böttcher, Jürgen; Strebel, O.; Voerkelius, S.; Schmidt, Hanns‐Ludwig

doi:10.1016/0022-1694(90)90068-9

Cited by 704 publications

(498 citation statements)

References 6 publications

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“…5). This trend cannot result from denitrification (dashed arrow; Böttcher et al, 1990;Kendall,1998;Granger et al, 2010), but might be explained by an impact of NO (Table 1; Kendall and Doctor, 2004;Michalski et al, 2004a;Thiemens, 2001). In Fig.…”

Section: Stable Isotopes Of Nitrate Origin and Potential Overprintsmentioning

confidence: 97%

“…In modern groundwater the isotope composition of NO Böttcher et al, 1990;Zhang et al, 2010Zhang et al, , 2012Saccon et al, 2013). This overprint can be followed by a characteristic superimposition of the sulfur and oxygen isotope composition of dissolved SO 2− 4 (e.g.…”

Section: Stable Isotopes Of Nitrate Origin and Potential Overprintsmentioning

confidence: 99%

“…In addition, a reaction of NO − 3 with pyrite (FeS 2 ) minerals in the aquifers can act as a potential NO − 3 sink, which has already been shown for European shallow aquifers (e.g. Böttcher et al, 1990;Zhang et al, 2012). This requires the analyses of the stable isotope signatures of dissolved SO 2− 4 .…”

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confidence: 98%

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<sup>17</sup>O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert

et al. 2014

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Section: Stable Isotopes Of Nitrate Origin and Potential Overprintsmentioning

confidence: 97%

Section: Stable Isotopes Of Nitrate Origin and Potential Overprintsmentioning

confidence: 99%

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<sup>17</sup>O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert

et al. 2014

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“…Such an isotopic signature could theoretically be sourced from NO 3 -containing mineral fertilizers (Kendall, 1998) but in this case elevated nitrate concentrations would be expected. During denitrification in a closed system, it is expected that as nitrate concentrations decrease the remaining nitrate becomes progressively enriched in 15 N and 18 O (Mariotti et al, 1988;Böttcher et al, 1990). Plotting nitrate concentrations vs. δ 15 N values of nitrate containing samples provides some evidence that these samples may have been affected by denitrification (Fig.…”

Section: Nitrogen and Oxygen Isotope Ratios Of Nitratesmentioning

confidence: 98%

Redox controls on methane formation, migration and fate in shallow aquifers

Humez¹,

Mayer²,

Nightingale³

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract. Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish (a) natural in situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. This study combines aqueous and gas (dissolved and free) geochemical and isotope data from 372 groundwater samples obtained from 186 monitoring wells of the provincial Groundwater Observation Well Network (GOWN) in Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. We investigated whether methane occurring in shallow groundwater formed in situ, or whether it migrated into the shallow aquifers from elsewhere in the stratigraphic column. It was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of biogenic methane ( > 0.01 mM or > 0.2 mg L −1 ), characterized by δ 13 C CH 4 values < −55 ‰, occurred in anoxic Na-Cl, Na-HCO 3 , and Na-HCO 3 -Cl type groundwaters with negligible concentrations of nitrate and sulfate suggesting that methane was formed in situ under methanogenic conditions for 39.1 % of the samples. In only a few cases (3.7 %) was methane of biogenic origin found in more oxidizing shallow aquifer portions suggesting limited upward migration from deeper methanogenic aquifers. Of the samples, 14.1 % contained methane with δ 13 C CH 4 values > −54 ‰, potentially suggesting a thermogenic origin, but aqueous and isotope geochemistry data revealed that the elevated δ 13 C CH 4 values were caused by microbial oxidation of biogenic methane or postsampling degradation of low CH 4 content samples rather than migration of deep thermogenic gas. A significant number of samples (39.2 %) contained methane with predominantly biogenic C isotope ratios (δ 13 C CH 4 < −55 ‰) accompanied by elevated concentrations of ethane and sometimes trace concentrations of propane. These gases, observed in 28.1 % of the samples, bearing both biogenic (δ 13 C) and thermogenic (presence of C 3 ) characteristics, are most likely derived from shallow coal seams that are prevalent in the Cretaceous Horseshoe Canyon and neighboring formations in which some of the groundwater wells are completed. The remaining 3.7 % of samples were not assigned because of conflicting parameters in the data sets or between replicates samples. Hence, despite quite variable gas concentrations and a wide range of δ 13 C CH 4 values in baseline groundwater samples, we found no conclusive evidence for deep thermogenic gas migration into shallow aqu...

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“…The enrichment factor is negative for most of the nitrogen transformation processes, and in the case of denitrification it has been defined with a range from −40‰ to −3.5‰, which reveals a variety of environmental and experimental conditions [34][35][36]. The enrichment factor can be estimated from the evolution of the isotopic composition of the residual reactant [18] defined as:…”

Section: Stable Isotope Calculationsmentioning

confidence: 99%

Tracing Nitrate-Nitrogen Sources and Modifications in a Stream Impacted by Various Land Uses, South Portugal

Yevenes

Soetaert

Mannaerts

2016

Water

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Abstract:The identification of nitrate-nitrogen (NO 3 -N) origin is important in the control of surface and ground water quality. These are the main sources of available drinking water. Stable isotopes ( 15 N and 18 O) for NO 3 -N and along with a 1-D reactive transport model were used to study the origin and processes that lead to nitrogen transformation and loss in a major stream that flows into a reservoir within an intensively cultivated catchment area (352 km 18 O values in surface water samples from the stream and wells indicated that the dominant NO 3 -N sources were derived mainly from the soil and fertilizers. There was also significant nitrification in surface water at the head of the stream. Sediment pore waters showed high NO 3 -N values near the sediment-water interface (reaching 25 mg·N·L −1 ) and NO 3 -N concentrations sharply decreasing with sediment depth, suggesting significant NO 3 -N consumption. Denitrification was also detected using the 15 N signature in upstream waters, but not downstream where very low NO 3 -N levels were measured. In the stream, the calculated isotopic enrichment factor for NO 3 -N was −2.9‰ for 15 N and −1.78 for 18 O, this indicates that denitrification accounts for 7.8% to 48% of nitrate removal.

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Using isotope fractionation of nitrate-nitrogen and nitrate-oxygen for evaluation of microbial denitrification in a sandy aquifer

Cited by 704 publications

References 6 publications

<sup>17</sup>O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert

<sup>17</sup>O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert

Redox controls on methane formation, migration and fate in shallow aquifers

Tracing Nitrate-Nitrogen Sources and Modifications in a Stream Impacted by Various Land Uses, South Portugal

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Using isotope fractionation of nitrate-nitrogen and nitrate-oxygen for evaluation of microbial denitrification in a sandy aquifer

Cited by 704 publications

References 6 publications

&lt;sup&gt;17&lt;/sup&gt;O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert

&lt;sup&gt;17&lt;/sup&gt;O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert

Redox controls on methane formation, migration and fate in shallow aquifers

Tracing Nitrate-Nitrogen Sources and Modifications in a Stream Impacted by Various Land Uses, South Portugal

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<sup>17</sup>O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert

<sup>17</sup>O excess traces atmospheric nitrate in paleo-groundwater of the Saharan desert