dc.contributor.author | Thrane, Jan-Erik | |
dc.contributor.author | de Wit, Heleen | |
dc.contributor.author | Blakseth, Tomas Adler | |
dc.contributor.author | Skancke, Liv Bente | |
dc.contributor.author | Garmo, Øyvind Aaberg | |
dc.date.accessioned | 2020-10-19T06:57:06Z | |
dc.date.available | 2020-10-19T06:57:06Z | |
dc.date.created | 2020-10-16T14:36:05Z | |
dc.date.issued | 2020 | |
dc.identifier.isbn | 978-82-577-7273-4 | |
dc.identifier.issn | 1894-7948 | |
dc.identifier.uri | https://hdl.handle.net/11250/2683478 | |
dc.description | Project manager Øyvind Garmo | en_US |
dc.description.abstract | Concentrations of total nitrogen (TotN) in freshwater monitoring programs were unreliable for a limited period, probably because of inadequate sample digestion when using a modified version of method NS 4743 (“method A”) for TotN analysis. The method resulted in underestimation of TotN, especially for humus-rich surface waters. Where re-analysis of samples with the original NS 4743 method (“method B”) is not possible, TotN may be corrected using a regression model fitted to ca. 1000 freshwater samples with analytical results from both method A (likely resulting in biased TotN concentrations; TotNold) and method B (resulting in presumably correct values; TotNnew). Here we present the dataset, the correction model, and a validation of the model using independent datasets. The regression model used TotNold and TOC and their interaction as predictors, and had an R2 of 0.956 and a root mean squared error (RMSE) of 31.87 μg N/L. The model predicted TotNnew well when tested on independent datasets from lakes and headwater streams. We recommend that the function is used to estimate TotN in long-term monitoring programs of lakes and headwater streams (1-3 order streams) where TotN was analysed with the modified standard method (method A), but not for rivers (>6-order streams) since the difference between TotN from the two methods was not significant for these water types. | en_US |
dc.language.iso | eng | en_US |
dc.publisher | Norsk institutt for vannforskning | en_US |
dc.relation.ispartof | NIVA-rapport | |
dc.relation.ispartofseries | NIVA-rapport;7538 | |
dc.rights | Navngivelse-Ikkekommersiell-DelPåSammeVilkår 4.0 Internasjonal | * |
dc.rights.uri | http://creativecommons.org/licenses/by-nc-sa/4.0/deed.no | * |
dc.subject | Total nitrogen | en_US |
dc.subject | Total nitrogen | en_US |
dc.subject | Analysemetoder | en_US |
dc.subject | Analytical methods | en_US |
dc.subject | Overvåking | en_US |
dc.subject | Monitoring | en_US |
dc.subject | Regresjon | en_US |
dc.subject | Regression | en_US |
dc.title | Correcting for bias in freshwater total nitrogen concentrations obtained with a modified standard (NS4743) method | en_US |
dc.title.alternative | Korrigering av skjevhet i konsentrasjoner av total nitrogen målt med en modifisert standard (NS4743) metode. | en_US |
dc.type | Research report | en_US |
dc.description.version | publishedVersion | en_US |
dc.rights.holder | © Norsk institutt for vannforskning/Norwegian Institute for Water Research.
The publication can be cited freely if the source is stated. | en_US |
dc.subject.nsi | VDP::Matematikk og naturvitenskap: 400 | en_US |
dc.subject.nsi | VDP::Mathematics and natural scienses: 400 | en_US |
dc.source.pagenumber | 22 | en_US |
dc.source.issue | 7538 | en_US |
dc.identifier.cristin | 1840208 | |
cristin.ispublished | true | |
cristin.fulltext | original | |