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dc.contributor.authorMcAleer, E.B.
dc.contributor.authorCoxon, C.E.
dc.contributor.authorRichards, Karl G.
dc.contributor.authorJahangir, M.M.R.
dc.contributor.authorGrant, Jim
dc.contributor.authorMellander, Per-Erik
dc.date.accessioned2017-06-19T15:52:14Z
dc.date.available2017-06-19T15:52:14Z
dc.date.issued20/02/2017
dc.identifier.citationE.B. McAleer, C.E. Coxon, K.G. Richards, M.M.R Jahangir, J. Grant, Per.E. Mellander, Groundwater nitrate reduction versus dissolved gas production: A tale of two catchments, Science of The Total Environment, 2017, 586, 372-389, https://doi.org/10.1016/j.scitotenv.2016.11.083en_GB
dc.identifier.issn0048-9697
dc.identifier.urihttp://hdl.handle.net/11019/1155
dc.descriptionpeer-revieweden_GB
dc.description.abstractAt the catchment scale, a complex mosaic of environmental, hydrogeological and physicochemical characteristics combine to regulate the distribution of groundwater and stream nitrate (NO3−). The efficiency of NO3− removal (via denitrification) versus the ratio of accumulated reaction products, dinitrogen (excess N2) & nitrous oxide (N2O), remains poorly understood. Groundwater was investigated in two well drained agricultural catchments (10 km2) in Ireland with contrasting subsurface lithologies (sandstone vs. slate) and landuse. Denitrification capacity was assessed by measuring concentration and distribution patterns of nitrogen (N) species, aquifer hydrogeochemistry, stable isotope signatures and aquifer hydraulic properties. A hierarchy of scale whereby physical factors including agronomy, water table elevation and permeability determined the hydrogeochemical signature of the aquifers was observed. This hydrogeochemical signature acted as the dominant control on denitrification reaction progress. High permeability, aerobic conditions and a lack of bacterial energy sources in the slate catchment resulted in low denitrification reaction progress (0–32%), high NO3− and comparatively low N2O emission factors (EF5g1). In the sandstone catchment denitrification progress ranged from 4 to 94% and was highly dependent on permeability, water table elevation, dissolved oxygen concentration solid phase bacterial energy sources. Denitrification of NO3 − to N2 occurred in anaerobic conditions, while at intermediate dissolved oxygen; N2O was the dominant reaction product. EF5g1 (mean: 0.0018) in the denitrifying sandstone catchment was 32% less than the IPCC default. The denitrification observations across catchments were supported by stable isotope signatures. Stream NO3− occurrence was 32% lower in the sandstone catchment even though N loading was substantially higher than the slate catchment.en_GB
dc.description.sponsorshipTeagasc Walsh Fellowship Programmeen_GB
dc.language.isoenen_GB
dc.publisherElsevieren_GB
dc.relation.ispartofseriesScience of the Total Environment;vol 586
dc.subjectDenitrificationen_GB
dc.subjectExcess N2en_GB
dc.subjectN2Oen_GB
dc.subjectDissolved oxygenen_GB
dc.subjectPollutant swappingen_GB
dc.subjectAgricultureen_GB
dc.subjectNitrous oxideen_GB
dc.subjectDinitrogenen_GB
dc.titleGroundwater nitrate reduction versus dissolved gas production: A tale of two catchmentsen_GB
dc.typeArticleen_GB
dc.identifier.rmisMTMC-0328-6300
dc.identifier.doihttps://doi.org/10.1016/j.scitotenv.2016.11.083
dc.contributor.sponsorTeagasc Walsh Fellowship Programme
refterms.dateFOA2018-01-12T09:01:14Z


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