Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2018
Sammendrag
I denne rapporten er det fremstilt resultater fra beregninger av erosjon og fosforavrenning fra jordbruksarealer i nedbørfeltet til Rakkestadelva. I tillegg er det laget et kart som kan brukes som utgangspunkt for å vurdere risiko for fure-erosjon. Enkle, empiriske modeller er brukt for å framskaffe estimater for tilførsler under dagens drift (2016) og for ulike scenarier. Slike resultater er forbundet med en rekke usikkerheter, og det anbefales at man fokuserer på relative forskjeller mellom områder og ulike driftsformer, heller enn på absolutte nivåer for jord- og fosfortap. ...
Sammendrag
The report presents results from monitoring of ten rivers and creeks in the Halden Watershed in the period 1 May 2017 to 1 May 2018. Water samples were collected every 14th day and analysed for total phosphorous (TP) and suspended sediments (SS). Every 28th day the samples were also analysed for dissolved phosphate. Results from previous monitoring in the period May 1th 2012 to May 1th 2017 are found in Greipsland (2015), Greipsland (2016) and Greipsland (2017).
Sammendrag
Degradation of organic chemicals in natural soils depends on oxidation-reduction conditions. To protect our groundwater resources we need to understand the degradation processes under anaerobic conditions. Available iron and manganese oxides are used as electron acceptors for anaerobic degradation and are reduced to the dissolved form of metallic cations in pore water. To monitor this process is a challenge, because anaerobic conditions are difficult to sample directly without introducing oxygen. A few studies have shown an impact of iron reduction on spectral induced polarisation (SIP) signature, often associated with bacterial growth. Our objective is to study the impact of iron and manganese oxide dissolution, caused by degradation of an organic compound, with spectral induced polarisation signatures. Twenty-six vertical columns (30 cm high, inner diameter 4.6 cm) were filled with a sand rich in oxides (manganese and iron) with a static water table in the middle. In half of the columns, a 2 cm high contaminated layer was installed just above the water table. As the contaminant degrades, the initial oxygen is consumed and anaerobic conditions form Every three days over a period of one month, spectral induced polarisation (twenty frequencies between 5mHz and 10 kHz) data were collected on six columns: three contaminated replicates and three control replicates. Chemical analysis was done on twenty columns assigned for destructive water sampling, ten contaminated columns and ten control. The results show an increase of the real conductivity associated with the degradation processes, independent of frequency. Compared with the pore water electrical conductivity in the saturated zone, the real conductivity measurement revealed the formation of surface conductivity before iron was released in the pore water. In parallel, we also observed an evolution of the imaginary conductivity in both saturated and unsaturated zones at frequencies below 1 Hz. Overall, the anaerobic reduction of iron and manganese oxide during the organic degradation increased both the conductive and polarisation component of the complex conductivity.
Sammendrag
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Forfattere
Isaiah Nyagumbo Mehreteab Tesfai Sekhar Udaya Nagothu Peter Setimela James K. Karanja Munyaradzi Mutenje Connie MademboSammendrag
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Forfattere
Yanliang Wang Erik Lysøe Tegan Armarego-Marriott Alexander Erban Lisa Paruch Andre van Eerde Ralph Bock Jihong Liu ClarkeSammendrag
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Forfattere
Roland Bol Gerard Gruau Per-Erik Mellander Rémi Dupas Marianne Bechmann Eva Skarbøvik Magdalena Bieroza Faruk Djodjic Miriam Glendell Philip Jordan Bas van der Grift Michael Rode Erik Smolders Mieke Verbeeck Sen Gu Erwin Klumpp Ina Pohle Maelle Fresne Chantal Gascuel-OdouxSammendrag
In this paper, we outline several recent insights for the priorities and challenges for future research for reducing phosphorus (P) based water eutrophication in the agricultural landscapes of Northwest Europe.We highlight that new research efforts best be focused on headwater catchments as they are a key influence on the initial chemistry of the larger river catchments, and here many management interventions are most effectively made. We emphasize the lack of understanding on how climate change will impact on P losses from agricultural landscapes. Particularly, the capability to disentangle current and future trends in P fluxes, due to climate change itself, from climate driven changes in agricultural management practices and P inputs. Knowing that, future climatic change trajectories for Western Europe will accelerate the release of the most bioavailable soil P. We stress the ambiguities created by the large varieties of sources and storage/transfer processes involved in P emissions in landscapes and the need to develop specific data treatment methods or tracers able to circumvent them, thereby helping catchment managers to identify the ultimate P sources that most contribute to diffuse P emissions. We point out that soil and aqueous P exist not only in various chemical forms, but also in range of less considered physical forms e.g., dissolved, nanoparticulate, colloidal and other particulates, all affected differently by climate as well as other environmental factors, and require bespoke mitigation measures. We support increased high resolution monitoring of headwater catchments, to not only help verify the effectiveness of catchments mitigation strategies, but also add data to further develop new water quality models (e.g., those include Fe-P interactions) which can deal with climate and land use change effects within an uncertainty framework. We finally conclude that there is a crucial need for more integrative research efforts to deal with our incomplete understanding of the mechanisms and processes associated with the identification of critical source areas, P mobilization, delivery and biogeochemical processing, as otherwise even highintensity and high-resolution research efforts will only reveal an incomplete picture of the full global impact of the terrestrial derived P on downstream aquatic and marine ecosystems.
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