Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2000
Sammendrag
No abstract has been registered
Forfattere
Dan Aamlid Natalya Vassilieva Per Arild Aarrestad Michael L. Gytarsky S. Lindmo Rodion Karaban Vladimir Korotkov Tord K. Rindal V. Kuzmicheva Kåre Olav VennSammendrag
Six sites for forest ecosystem monitoring were established to perform a long-term study of effects of air pollution on pine forest ecosystems along a pollution gradient in the border areas between Norway and Russia. The main pollution source is a nickel smelter.Several methods and analyses were used to investigate different compartments of this northern boreal forest ecosystem. The differences in ecological condition and diversity observed among the research sites are probably due to the air pollution load in the area. The elevated concentrations of Ni and Cu detected in plant tissues, the reduced lichen vegetation on stems and on the forest floor, and the reduced or absent moss vegetation are the most obvious impacts in the investigated area.
Forfattere
Åke LindelöwSammendrag
No abstract has been registered
Sammendrag
No abstract has been registered
Forfattere
Torbjørn OkstadSammendrag
No abstract has been registered
Sammendrag
Nitrogen is among the most important plant nutrients, and the effects on forest trees of changes in the concentrations and fluxes of both inorganic and organic nitrogen need to be known. In Norway, much of the nitrogen present in natural waters is organic (Mulder et al., 2000), therefore this fraction can not be neglected. Work using glycine has shown that forest plants can take up some forms of organic nitrogen directly, without preliminary mineralisation (Nsholm et al., 1998).Amino acids and amino sugars appear to be the most important organic sources of nitrogen for plants, including Norway spruce (Picea abies (L.) Karst.) (Johnsson et al., 1999). Organic nitrogen occurs in different forms. In soils, the most important are heterocyclic compounds and amino acids (35 % and 40 % respectively, Schulten and Schnitzer, 1998). In soil waters, amino sugars may also be important (Michalzik and Matzner, 1999).At present, organic nitrogen is normally determined as the difference between total nitrogen and the sum of nitrogen in nitrate and ammonium. This is not entirely satisfactory, as there will be a certain amount of uncertainty in each of the three determinations required. The total uncertainty involved in the determination of organic nitrogen may then be quite large compared to the actual concentration, especially when most nitrogen is present as inorganic nitrogen.A method for the direct determination of organic nitrogen is therefore desirable. Because organic nitrogen generally has a higher molecular weight than inorganic nitrogen, it might be possible to separate organic from inorganic nitrogen using size fractionation methods. In 1998, we worked on the setting up of methods for the determination of amino acids and amino sugars in soil waters, and on the direct determination of organic nitrogen using equilibrium dialysis.
Forfattere
V.R. Nsolomo Halvor Solheim Kåre Olav VennSammendrag
No abstract has been registered
Forfattere
Erik Christiansen Alan A. Berryman Vincent R. Franceschi Trygve Krekling Paal Krokene Nina Elisabeth Nagy Halvor SolheimSammendrag
No abstract has been registered
Forfattere
Staffan Jacobson Mikko Kukkola E. Mälkönen Bjørn TveiteSammendrag
No abstract has been registered
Sammendrag
No abstract has been registered