Blar i NIVA Open Access Archive på forfatter "de Wit, Heleen"
-
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 ... -
Improved Environmental Status: 50 Years of Declining Fish Mercury Levels in Boreal and Subarctic Fennoscandia
Braaten, Hans Fredrik Veiteberg; Åkerblom, Staffan; Kahilainen, Kimmo Kalevi; Rask, Martti; Vuorenmaa, Jussi; Mannio, Jaakko; Malinen, Tommi; Lydersen, Espen; Poste, Amanda; Amundsen, Per-Arne; Kashulin, Nikolai; Kashulina, Tatiana; Terentjev, Petr; Christensen, Guttorm; de Wit, Heleen (Journal article; Peer reviewed, 2019)Temporally (1965–2015) and spatially (55°–70°N) extensive records of total mercury (Hg) in freshwater fish showed consistent declines in boreal and subarctic Fennoscandia. The database contains 54 560 fish entries (n: pike ... -
Long-term rise in riverine dissolved organic carbon concentration is predicted by electrolyte solubility theory
Monteith, Donald T.; Henrys, Peter A.; Hruška, Jakub; de Wit, Heleen; Krám, Pavel; Moldan, Filip; Posch, Maximilian; Räike, Antti; Stoddard, John L.; Shilland, Ewan M.; Gloria Pereira, Pereira; Evans, Chris D. (Peer reviewed; Journal article, 2023)The riverine dissolved organic carbon (DOC) flux is of similar magnitude to the terrestrial sink for atmospheric CO2, but the factors controlling it remain poorly determined and are largely absent from Earth system models ... -
Long-term rise in riverine dissolved organic carbon concentration is predicted by electrolyte solubility theory
Monteith, Donald T.; Henrys, Peter A.; Hruška, Jakub; de Wit, Heleen; Krám, Pavel; Moldan, Filip; Posch, Maximilian; Räike, Antti; Stoddard, John L.; Shilland, Ewan M.; Pereira, M. Gloria; Evans, Chris D. (Peer reviewed; Journal article, 2023)The riverine dissolved organic carbon (DOC) flux is of similar magnitude to the terrestrial sink for atmospheric CO2, but the factors controlling it remain poorly determined and are largely absent from Earth system models ... -
Mercury in fish from Norwegian lakes: The complex influence of aqueous organic carbon
Braaten, Hans Fredrik Veiteberg; de Wit, Heleen; Larssen, Thorjørn; Poste, Amanda (Journal article; Peer reviewed, 2018)Mercury (Hg) concentrations in water and biota are often positively correlated to organic matter (OM), typically measured as total or dissolved organic carbon (TOC/DOC). However, recent evidence suggests that higher OM ... -
Natural organic matter fractions and their removal in full-scale drinking water treatment under cold climate conditions in Nordic capitals
Krzeminski, Pawel; Vogelsang, Christian; Meyn, Thomas; Köhler, Stephan; Poutanen, Heikki; de Wit, Heleen; Uhl, Wolfgang (Journal article; Peer reviewed, 2019)Drinking water treatment plants (DWTPs) designed to remove natural organic matter (NOM) are challenged as concentrations of NOM in raw waters are increasing. Here, we assess seasonal differences in NOM quality and quantity, ... -
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 ... -
Oxygen dynamics in a boreal lake responds to long-term changes in climate, ice phenology, and DOC inputs
Couture, Raoul-Marie; de Wit, Heleen; Tominaga, Koji; Kiuru, Petri; Markelov, Igor (Journal article; Peer reviewed, 2015)Boreal lakes are impacted by climate change, reduced acid deposition, and changing loads of dissolved organic carbon (DOC) from catchments. We explored, using the process-based lake model MyLake, how changes in these ... -
Potential impacts of a future Nordic bioeconomy on surface water quality
Marttila, Hannu; Lepistö, Ahti; Tolvanen, Anne; Bechmann, Marianne; Kyllmar, Katarina; Juutinen, Artti; Wenng, Hannah Tabea; Skarbøvik, Eva; Futter, Martyn; Kortelainen, Pirkko; Rankinen, Katri; Hellsten, Seppo; Kløve, Bjørn; Kronvang, Brian; Kaste, Øyvind; Solheim, Anne Lyche; Bhattacharjee, Joy; Rakovic, Jelena; de Wit, Heleen (Peer reviewed; Journal article, 2020)Nordic water bodies face multiple stressors due to human activities, generating diffuse loading and climate change. The ‘green shift’ towards a bio-based economy poses new demands and increased pressure on the environment. ... -
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. -
Proceedings of the 33rd Task Force meeting of the ICP Waters Programme in Uppsala, May 9-11, 2017
Garmo, Øyvind Aaberg; de Wit, Heleen; Fölster, Jens; Garmo, Øyvind - Project manager (NIVA-rapport;7178, Research report, 2017)Proceedings of the 33rd Task Force meeting of the ICP Waters Programme in Uppsala, May 9-11, 2017. National contributions from Russia, Switzerland, and Moldova. -
Proceedings of the 34th Task Force meeting of the ICP Waters Programme in Warsaw, May 7-9, 2018
Garmo, Øyvind Aaberg; Ulańczyk, Rafał; de Wit, Heleen (NIVA-rapport;7298, Research report, 2018)Proceedings of the 34th Task Force meeting of the ICP Waters Programme in Warsaw, May 7-9, 2018. National contributions from Russia and Armenia.