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.
2008
Forfattere
Knut G Berdal Jihong Liu Clarke Merethe Aasmo Finne Helge Klungland Casper Linnestad Arne Mikalsen Anne Ingeborg Myhr Audun Helge Nerland Ingolf Nes Kaare Magne Nielsen Hilde-Gunn Opsahl Sorteberg Odd Egil Stabbetorp Vibeke ThraneSammendrag
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Sammendrag
Arthropods were collected by fogging the canopy of Scots pine Pinus sylvestris selected from a 2 km2 boreal forest area in Sigdal, Norway with the overall purpose to examine whether there were faunal differences in the representation of arthropods among mature and old trees, and specifically for this paper, the biting midges (Ceratopogonidae). Target trees were chosen as pairs, one mature (70-110 years) and one old (250 years or older) tree from six different stands. All knock-down treatments were performed in June and July 1999, before dawn and after a dry and windless night. Knocked-down arthropods were collected in plastic funnels placed systematically on the ground. Funnels remained in place for circa one hour after treatment. Among the 61 species records new to Norway, the most frequently encountered taxon of invertebrates was Diptera, and the family of biting midges, Ceratopogonidae, comprised 30 of 61 (49%) of all new records, compared with the overall species numbers showing 40 biting midges of 193 recorded species (21%). Among the Ceratopogonidae new to Norway, two species new to science and two first records from Europe were found. Coleman rarefaction curves were constructed by running 500 iterations without replacements using EstimateS and showed that there were significantly more new records of Diptera in old trees in comparison with mature trees. A similar pattern of significance (by comparing standard deviations estimated by EstimateS) was found for Diptera when Ceratopogonidae was excluded. New species records of Ceratopogonidae were more common in old trees than in mature trees, although not significantly so. No predominance of new records in old trees was found for arthropods other than Diptera. Old trees are rare and may provide a variety of resources (e.g. resting sites, places to over-winter, hiding places, sites for oviposition, larval habitat, etc.) that are rarely found in younger trees. Thus, the high number of new species records probably result from studying a whole arthropod taxon (Diptera) in a part of a forest ecosystem (canopies) with a suite of microhabitats (old pine trees) that in combination has been poorly investigated earlier.
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A major challenge in studies on the environmental fate of nanoparticles is to detect their presence and distinguish them from natural nanoparticles and the large variety of amorphous materials present in environmental media. Neutron activation of mineral particles enables the production of radio-labelled NPs without surface modification, and enabling both localisation and quantification within a matrix or organism. The method is extremely sensitive, allowing detection at parts per billion or lower. Thus, any such labelled NP can be detected in individual fractions or compartments in soil or sediments (associated to clay, colloids, humic material, etc) or localized within organisms and their specific tissues following dissection (fish gills, digestive tract, liver, brain, etc) or by autoradiography. An added advantage of gamma-emitting radionuclides is that they do not need separation from the matrix for counting, thus uptake and extraction can be followed on live animals. Thus time-course experiments in vivo may be conducted to study metabolism and exposure, two aspects that are currently lacking in the body of ecotoxicological knowledge about ENPs. This paper will report some of the conditions, advantages and experimental opportunities of using neutron activation as a tool to study ENPs in environmental samples, with demonstration of the application of the technique in studies on Ag and Co nanoparticle uptake and metabolism in the earthworm Eisenia fetida.
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Based on data from published nitrogen balances at the farm level, it is shown that fams combining grazing with own silage/hay production for the winter period are highly nitrogen efficient
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Forfattere
Adam ParuchSammendrag
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Lise GrøvaSammendrag
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