Browsing NIVA-rapporter by Author "de Wit, Heleen"
Now showing items 1-20 of 28
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Atmospheric deposition and lateral transport of mercury in Norwegian drainage basins: A mercury budget for Norway
Braaten, Hans Fredrik Veiteberg; Gundersen, Cathrine Brecke; Sample, James Edward; Selvik, John Rune; de Wit, Heleen (NIVA-rapport;7310, Research report, 2018)Reduced atmospheric loading of mercury (Hg) can improve the environmental status of freshwaters and coastal ecosystems. Sparse data limit impact assessments of changes in atmospheric Hg on aquatic ecosystems. Here, a Hg ... -
Biodiversity in freshwaters: temporal trends and response to water chemistry (ICP Waters report 114/2013)
Velle, Gaute; Telford, Richard J.; Curtis, Chris; Eriksson, Lars; Fjellheim, Arne; Frolova, Marina; Fölster, Jens; Grudule, Natalja; Halvorsen, Godtfred A.; Hildrew, Alan; Hoffmann, Andreas; Indriksone, Iveta; Kamasová, Lenka; Kopáèek, Jiøí; Orton, Stuart; Krám, Pavel; Monteith, Don T.; Senoo, Takaaki; Shilland, Ewan M.; Stuchlík, Evžen; Wiklund, Magda-Lena; de Wit, Heleen; Skjelkvaale, Brit Lisa (NIVA-rapport;6580, Research report, 2013-10)This report describes trends in biological diversity of benthic invertebrates from acid-sensitive lakes and rivers sampled between 1982 and 2011 in the Czech Republic, Germany, Latvia, Norway, Sweden and the UK. The results ... -
Biodiversity of macro-invertebrates in acid-sensitive waters: trends and relations to water chemistry and climate. ICP Waters report 127/2016
Velle, Gaute; Mahlum, Shad; Monteith, Don T.; de Wit, Heleen; Arle, Jens; Eriksson, Lars; Fjellheim, Arne; Frolova, Marina; Fölster, Jens; Grudule, Natalja; Halvorsen, Godtfred A.; Hildrew, Alan; Hruška, Jakub; Indriksone, Iveta; Kamasová, Lenka; Kopáček, Jiří; Krám, Pavel; Orton, Stuart; Senoo, Takaaki; Shilland, Ewan M.; Stuchlík, Evžen; Telford, Richard J.; Ungermanová, Lenka; Wiklund, Magda-Lena; Wright, Richard F. (NIVA-rapport;7077, Research report, 2016-09)This is a study of the international impact of acid emission reductions on vulnerable freshwater biodiversity of benthic macroinvertebrates. In order to properly attribute impacts it is necessary to also incorporate the ... -
Biological intercalibration: Invertebrates 1713 (ICP Waters report 118/2014)
Fjellheim, Arne; Johannessen, Arne; Landås, Torunn Svanevik; de Wit, Heleen (NIVA-rapport;6662, Research report, 2014-04)The 17th intercalibration of invertebrates in the ICP Waters programme had contribution from four laboratories. The laboratories identified a very high portion of the individuals in the test samples, usually > 95% of the ... -
Biological intercalibration: Invertebrates 1814
Fjellheim, Arne; Johannessen, Arne; Landås, Torunn Svanevik (NIVA-rapport;6761, Research report, 2014)The 18th intercalibration of invertebrates in the ICP Waters programme had contribution from three laboratories. The laboratories identified a very high portion of the individuals in the test samples, > 95% of the total ... -
Chemical and biological recovery in acid-sensitive waters: trends and prognosis (ICP Waters report 119/2015)
Garmo, Øyvind Aaberg; de Wit, Heleen; Fjellheim, A (NIVA-rapport;6847, Research report, 2015)We present a trend analysis of surface water chemistry in in acid-sensitive lakes and rivers in Europe and North America, for the period 2000 to 2011, combined with a prognosis for water chemistry in Europe in 2020. Also, ... -
Correcting for bias in freshwater total nitrogen concentrations obtained with a modified standard (NS4743) method
Thrane, Jan-Erik; de Wit, Heleen; Blakseth, Tomas Adler; Skancke, Liv Bente; Garmo, Øyvind Aaberg (NIVA-rapport;7538, Research report, 2020)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”) ... -
Effects of nitrogen on nutrient-limitation in oligotrophic northern surface waters
Thrane, Jan-Erik; de Wit, Heleen; Austnes, Kari (NIVA-rapport;7680, Research report, 2021)Nitrogen deposition has a potentially eutrophying impact on oligotrophic freshwaters. Here we present a data analysis and a literature review with a joint focus on nitrogen (N) limitation in oligotrophic lakes and rivers. ... -
Evaluation of the IKEU programme. An evaluation of the programme’s organization, its organs, financing and contributions
Kaste, Øyvind; Schartau, Ann Kristin; de Wit, Heleen; Vogt, Rolf David (NIVA-rapport;7895-2023, Research report, 2023)IKEU (Integrated Studies of the Effects of Liming Acidified Waters) is the national monitoring programme for long-term effects of liming in Sweden. The main focus of IKEU is to study the long-term effects of liming on lakes ... -
Gjødsling av skog - vurdering av eksisterende hensynssone og tak for nitrogengjødsling på bakgrunn av ny kunnskap
Kaste, Øyvind; Skarbøvik, Eva; Clarke, Nicholas; de Wit, Heleen (NIVA-rapport;7663, Research report, 2021)I 2014 ble det utgitt en rapport om skoggjødsling som klimatiltak, hvor det ut fra hensyn til vannmiljø ble stipulert en hensynssone for nitrogengjødsling av skog og et arealmessig tak for gjødsling innenfor denne sonen. ... -
The impact of the spring 2020 snowmelt floods on physicochemical conditions in three Norwegian river-fjord-coastal systems
Poste, Amanda; Kaste, Øyvind; Frigstad, Helene; de Wit, Heleen; Harvey, Therese; Valestrand, Louise; Deininger, Anne; Bryntesen, Tina; Delpech, Lisa-Marie; Christensen, Guttorm (NIVA-rapport;7651, Research report, 2021)Due to very high snow accumulation in the winter of 2019/2020, the Norwegian Water Resources and Energy Directorate (NVE) in late May 2020 issued flood forecasts predicting extremely high flood risk for parts of northern ... -
Nitrogen in surface waters: time trends and geographical patterns explained by deposition levels and catchment characteristics
Austnes, Kari; Hjermann, Dag Øystein; Sample, James Edward; Wright, Richard Frederic; Kaste, Øyvind; de Wit, Heleen (NIVA-rapport;7728-2022, Research report, 2022)The report presents a statistical analysis of controls (deposition, land cover, climate) on spatial variability and long-term trends (1992-2016) in surface water concentrations of nitrate (NO3) and carbon to nitrogen (C/N) ... -
Overvåking av referanseelver - Utprøving av klassifiseringssystemet for basisovervåking i referansevassdrag
Sandin, Leonard; Thrane, Jan-Erik; Persson, Jonas; Kile, Maia Røst; Bækkelie, Knut Andreas; Myrvold, Knut Marius; Garmo, Øyvind Aaberg; Grung, Merete; Calidonio, Jose-Luis; de Wit, Heleen; Moe, Therese Fosholt (NIVA-rapport;7640, Research report, 2021)Overvåkingsprogrammet for referanseelver har pågått siden 2017, og 2020 var andre år med undersøkelser i de 33 vannforekomstene som første gang ble undersøkt i 2018. Vannforekomstene dekker mange ulike elvetyper i flere ... -
Overvåking av referanseelver 2017. Basisovervåking i henhold til vannforskriften
Moe, Therese Fosholt; Thrane, Jan-Erik; Bækkelie, Knut Andreas Eikland; Myrvold, Knut Marius; Olstad, Kjetil; Garmo, Øyvind Aaberg; Grung, Merete; de Wit, Heleen (NIVA-rapport;7259, Research report, 2018)Overvåking av referanseelver startet opp i 2017, og 47 antatte referansevannforekomster ble undersøkt. Vannforekomstene dekket alle økoregioner og mange ulike elvetyper, men det er knyttet relativt stor usikkerhet til en ... -
Overvåking av referanseelver 2017. Basisovervåking i henhold til vannforskriften
Moe, Therese Fosholt; Thrane, Jan-Erik; Persson, Jonas; Bækkelie, Knut Andreas Eikland; Myrvold, Knut Marius; Olstad, Kjetil; Garmo, Øyvind Aaberg; Grung, Merete; de Wit, Heleen (NIVA-rapport;7259, Research report, 2018)Overvåking av referanseelver startet opp i 2017, og 47 antatte referansevannforekomster ble undersøkt. Vannforekomstene dekket alle økoregioner og mange ulike elvetyper, men det er knyttet relativt stor usikkerhet til en ... -
Overvåking av referanseelver 2018. Basisovervåking i henhold til vannforskriften
Moe, Therese Fosholt; Persson, Jonas; Bækkelie, Knut Andreas Eikland; Myrvold, Knut Marius; Garmo, Øyvind Aaberg; Grung, Merete; Hindar, Atle; Guerrero Calidonio, Jose-Luis; de Wit, Heleen (NIVA-rapport;7378, Research report, 2019)Overvåking av referanseelver har vært gjennomført over to år, og i andre år (2018) ble 34 antatte referansevannforekomster undersøkt. Vannforekomstene dekket mange ulike elvetyper i økoregionene Finnmark, Vestlandet og ... -
Overvåking av referanseelver 2019. Basisovervåking i henhold til vannforskriften
Thrane, Jan-Erik; Persson, Jonas; Kile, Maia Røst; Bækkelie, Knut Andreas; Myrvold, Knut Marius; Garmo, Øyvind Aaberg; Grung, Merete; Calidonio, Jose-Louis Guerrero; de Wit, Heleen; Moe, Therese Fosholt (NIVA-rapport;7485, Research report, 2020)Rapporten presenterer resultatene fra 2019, som var andre år med overvåking i 40 vannforekomster. Vannforekomstene dekket alle økoregioner og mange ulike elvetyper, men det er knyttet relativt stor usikkerhet til en del ... -
Proceedings of the 29th Task Force meeting of the ICP Waters Programme in Český Krumlov, Czech Republic 1st –3rd October, 2013 (ICP Waters report 117/2014)
de Wit, Heleen; Wathne, Bente Margrethe; Hruska, Jakub (NIVA-rapport; 6643, Research report, 2014-03)The report contains Proceedings of the 29th Task Force meeting of the ICP Waters Programme in Český Krumlov, Czech Republic, October 1 – 3, 2013, including national contributions from Armenia, Canada, the Czech Republic, ... -
Proceedings of the 30th Task Force meeting of the ICP Waters Programme in Grimstad, Norway 14th –16th October, 2014
de Wit, Heleen; Wathne, Bente Margrethe; de Wit, Heleen (NIVA-rapport;6793, Research report, 2015)Proceedings of the 30th Task Force meeting of the ICP Waters Programme in Grimstad, Norway, October 14 – 16, 2014. National contributions from Russia, Finland, Canada, Sweden, and Norway. -
Proceedings of the 32nd Task Force meeting of the ICP Waters Programme in Asker, Oslo, May 24-26, 2016. ICP Waters report 128/2016
Valinia, Salar; de Wit, Heleen; de Wit, Heleen - Project manager (NIVA-rapport;7090, Research report, 2016-11)Proceedings of the 32nd Task Force meeting of the ICP Waters Programme in Asker, Norway, May 24-26, 2016. National contributions from Russia and Norway.