Denitrification coupled to pyrite oxidation and changes in groundwater quality in a shallow sandy aquifer

Zhang, Yan-Chun; Slomp, Caroline P.; Broers, Hans Peter; Passier, Hilde F.; Cappellen, Philippe Van

doi:10.1016/j.gca.2009.08.026

Cited by 119 publications

(95 citation statements)

References 26 publications

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“…The importance of DOC as an electron donor in aquifers depends on the subsurface setting [35]. Where solid phase components, such as organic matter and pyrite in the aquifer matrix are dominant [36], the electron donors are not replenished and can gradually be depleted with time [7]. Recent studies confirm the important role of pyrite for NO 3 2 removal in groundwater [35].…”

Section: Discussionmentioning

confidence: 99%

“…As O 2 becomes limiting in the saturated zone, heterotrophic microorganisms increasingly switch to NO 3 2 as an electron acceptor for the oxidation of organic C. This organic C may be present in either dissolved form or as part of the sediment matrix. If pyrite is present in subsurface sediments, denitrification coupled to pyrite oxidation may become the dominant removal process [7]. Pyrite is a common iron disulfide mineral, and is often found in association with unconsolidated marine deposits in the terrestrial subsurface and in association with coal and shale deposits.…”

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confidence: 99%

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Global trends and uncertainties in terrestrial denitrification and N ₂ O emissions

Bouwman

Beusen

Griffioen

et al. 2013

Phil. Trans. R. Soc. B

244

188

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Soil nitrogen (N) budgets are used in a global, distributed flow-path model with 0.5° × 0.5° resolution, representing denitrification and N 2 O emissions from soils, groundwater and riparian zones for the period 1900–2000 and scenarios for the period 2000–2050 based on the Millennium Ecosystem Assessment. Total agricultural and natural N inputs from N fertilizers, animal manure, biological N 2 fixation and atmospheric N deposition increased from 155 to 345 Tg N yr −1 (Tg = teragram; 1 Tg = 10 12 g) between 1900 and 2000. Depending on the scenario, inputs are estimated to further increase to 408–510 Tg N yr −1 by 2050. In the period 1900–2000, the soil N budget surplus (inputs minus withdrawal by plants) increased from 118 to 202 Tg yr −1 , and this may remain stable or further increase to 275 Tg yr −1 by 2050, depending on the scenario. N 2 production from denitrification increased from 52 to 96 Tg yr −1 between 1900 and 2000, and N 2 O–N emissions from 10 to 12 Tg N yr −1 . The scenarios foresee a further increase to 142 Tg N 2 –N and 16 Tg N 2 O–N yr −1 by 2050. Our results indicate that riparian buffer zones are an important source of N 2 O contributing an estimated 0.9 Tg N 2 O–N yr −1 in 2000. Soils are key sites for denitrification and are much more important than groundwater and riparian zones in controlling the N flow to rivers and the oceans.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Global trends and uncertainties in terrestrial denitrification and N ₂ O emissions

Bouwman

Beusen

Griffioen

et al. 2013

Phil. Trans. R. Soc. B

244

188

View full text Add to dashboard Cite

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“…However, a growing body of research suggests that denitrification in most aquifers depends on matrix-derived, solid-phase electron donors (e.g. Fe 2+ , H 2 S) rather than surface-derived solutes (Green et al, 2008;Schwientek et al, 2008;Zhang et al, 2009;Torrento et al, 2010Torrento et al, , 2011. As a result, concentrations of dissolved organic matter and other electron donors may be a poor indicator of denitrification rates across aquifers, and spatial patterns within aquifers may reflect the distribution of these reactants within the aquifer matrix rather than substrate depletion along advective flowpaths.…”

Section: Introductionmentioning

confidence: 99%

Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

et al. 2012

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Abstract. Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N 2 gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N 2 is highly variable in space and inversely correlated with dissolved oxygen (O 2 ). Negative relationships between O 2 and δ 15 N NO3 across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong 15 N: 18 O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32 % of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source δ 15 N NO3 based on denitrification progression suggest that isotopically-enriched nitrate (NO − 3 ) in many springs of the UFA reflects groundwater denitrification rather than urban-or animal-derived inputs.

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“…A potential source of carbon that may have helped support continued denitrification is dead biomass produced from die-off of bacterial populations that increased during the initial period when ethanol was present in high concentrations. Additionally, given the observed reduction of resident sulfate to sulfide during the tests, the reoxidation of sulfide back to sulfate (and attendant use of nitrate as an electron acceptor) as redox conditions reverted to natural conditions may have helped sustain the low nitrate concentrations (e.g., Robertson et al 1996;Pauwels et al 1998;Tesoriero et al 2000;Schwientek et al 2008;Zhang et al 2009). …”

Section: Resultsmentioning

confidence: 99%

Ethanol Addition for Enhancing Denitrification at the Uranium Mill Tailing Site in Monument Valley, AZ

Borden

Brusseau

Carroll

et al. 2011

Water Air Soil Pollut

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Past mining and processing of uranium ore at a former uranium mining site near Monument Valley, AZ has resulted in nitrate contamination of groundwater. The objective of this study was to investigate the potential of ethanol addition for enhancing the reduction of nitrate in groundwater. The results of two pilot-scale field tests showed that the concentration of nitrate decreased, while the concentration of nitrous oxide (a product of denitrification) increased. In addition, changes in aqueous concentrations of sulfate, iron, and manganese indicated that the ethanol amendment caused a change in prevailing redox conditions. The results of compound-specific stable isotope analysis for nitrate-nitrogen indicated that the nitrate concentration reductions were biologically mediated. Denitrification rate coefficients estimated for the pilot tests were approximately 50 times larger than resident-condition (non-enhanced) values obtained from prior characterization studies conducted at the site. The nitrate concentrations in the injection zone have remained at levels three orders of magnitude below the initial values for many months, indicating that the ethanol amendments had a long-term impact on the local subsurface environment.

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Denitrification coupled to pyrite oxidation and changes in groundwater quality in a shallow sandy aquifer

Cited by 119 publications

References 26 publications

Global trends and uncertainties in terrestrial denitrification and N ₂ O emissions

Global trends and uncertainties in terrestrial denitrification and N ₂ O emissions

Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

Ethanol Addition for Enhancing Denitrification at the Uranium Mill Tailing Site in Monument Valley, AZ

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Denitrification coupled to pyrite oxidation and changes in groundwater quality in a shallow sandy aquifer

Cited by 119 publications

References 26 publications

Global trends and uncertainties in terrestrial denitrification and N 2 O emissions

Global trends and uncertainties in terrestrial denitrification and N 2 O emissions

Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

Ethanol Addition for Enhancing Denitrification at the Uranium Mill Tailing Site in Monument Valley, AZ

Contact Info

Product

Resources

About

Global trends and uncertainties in terrestrial denitrification and N ₂ O emissions

Global trends and uncertainties in terrestrial denitrification and N ₂ O emissions