Publikasjoner
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2002
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Dan AamlidSammendrag
Extended summary and conclusions The Pechenganikel combine in the Nikel-Zapolyarny area was established in 1933. During the first 30 years of production, 100 000 tons of sulphur dioxide (SO2) were emitted annually. Since 1971, nickel from the Norilsk ores in Siberia have been processed in the smelters. The Norilsk ore contains more sulphur than the Nikel ore. As a result of the processing of this sulphur-rich ore, emissions of SO2 increased rapidly, reaching 400 000 tons in 1979. Current annual emissions are much lower, about 150 000 tons. However, the present emission is still above the critical level for sensitive biota in the Nikel-Pasvik area. Investigations of soils show that the soil layers are contaminated by heavy metals (nickel and copper). The results also indicate an influence on soil fertility expressed as changes in base saturation (BS), cation exchange capacity (CEC) and soil acidity. According to the calculations (critical loads) future sulphur deposition has to be reduced to very low levels in order to stop the ongoing soil acidification. Air pollution influence has had severe effects on forest vegetation in the Nikel-Pasvik area. Trees, vascular plants, mosses and lichens are all affected. In the close vicinity of the smelters forests are dead or severely damaged. Visible injuries to vegetation caused by SO2 have some years been frequent. Symptoms are recognised on Scots pine (Pinus sylvestris) and downy birch (Betula pubescens), which are the dominant tree species in the region, and on other plants, e.g. dwarf birch (Betula nana) and bilberry (Vaccinium myrtillus). The species composition of the ground vegetation in the forest has been influenced, and epiphytic lichen vegetation has been severely influenced over large areas. Critical levels are exceeded on more than 3200 square kilometres of Russian and Norwegian territory. Air pollution has reduced invertebrate and animal diversity due to lack of forest vegetation and contamination of surface soils in the vicinity of the nickel smelters. Small vertebrates are impacted by an increased heavy metal content in the liver. However, no negative health effects to reindeer are foreseen. Long-term monitoring of water chemistry in lakes and rivers has revealed that extensive surface water acidification has taken place, particularly on the Norwegian side of the border. Critical loads are exceeded in large areas of Sør-Varanger municipality, especially in the Jarfjord area, and in areas situated around Nikel and Zapolyarny. However, on the Russian side, the contamination of lakes by the heavy metals (nickel and copper) is more severe than acidification, especially in the vicinity of the smelters, where damage to fish populations as well as phytoplankton and invertebrate communities are observed. Studies of human health in the Nikel-Pasvik area revealed no major health effects that can be ascribed to the air pollution by nickel and sulphur dioxide in the Nikel-Zapolyarny area or in the Pasvik valley. The most severe effects of air pollution in the border areas between Norway and Russia, caused by sulphur dioxide emission from Nikel and Zapolyarny, on the terrestrial and aquatic ecosystems seem to be on vegetation, surface water and soils, and thus also on other compartments of the ecosystem.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Dan AamlidSammendrag
Det er ikke registrert sammendrag
Forfattere
Wim de Vries Gert Jan Reinds H.F. van Dobben D. de Zwart Dan Aamlid P. Neville M. Posch J. Auée J.C.H. Voogd E.M. VelSammendrag
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Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Several strong westerly storms hit Western Norway during the winter of 1986-87. We studied the uptake, loss and visible effects of sea salt aerosols in Scots pine and Norway spruce. Foliage of was sampled at distances 0-100 km from the coastline between 59¢ª and 65¢ª N, and analysed for chloride, sodium and other elements. The range of chloride and sodium concentrations in needles was 0.5-5.0, and 0.1-3.0 mg g-1, respectively. The local variation was very large close to the coast. The relation to distance from the sea was improved by using distance from the nearest fjord rather than from the outer coastline. Other elements were less variable and not related to distance from the sea, or to sea salt concentrations. Only 1-10% of the needles sea salt content could be removed by 2 minutes washing in distilled water, and still much less of other elements. The amount of sea salt removed by washing was less related to distance from the sea than was the total content. Visible damage to the foliage occurred at chloride concentrations above 1 mg g-1 in the needles. Our conclusions are that analysis of the needles chloride or sodium content is a robust method for confirming damage to tree foliage by sea salt aerosols. Fjords as well as the ocean are significant sources of sea salt aerosols. Large local variation in salt deposition and damage will occur at a rugged coast. Nutrients and other elements are not significantly affected by the sea salt deposition. The use of chloride or sodium as a tracer for dry deposition should take into account not only the enrichment of these elements in canopy throughfall, but also the accumulation in the needles.
Forfattere
Håvard EikemoSammendrag
To investigate the variability in Phytophthora cactorum, 44 isolates from different geographic locations were collected. The isolates originated from various plant species, but the majority were crown rot and leather rot isolates from strawberry. DNA was extracted from all isolates, and examined by AFLP using seven different primer combinations. The resulting dendrogram revealed that isolates from crown rot in strawberries from all locations showed a very low degree of variation, and were clearly separated from the more variable leather rot isolates (of strawberry fruits) and isolates from other hosts. The separation of isolates with and without the ability to cause crown rot was confirmed in a pathogenesis test on strawberry plants. Several methods of screening strawberry cultivars for resistance to Phytophthora cactorum were tested and evaluated in this study. The methods involved both fresh and cold stored plants, and either mycelium on agar or a zoospore suspension was used to inoculate wounded or unwounded plants. Also inoculation of detached leaves and inoculation of plants in vitro were tested as possible methods of screening for resistance. Several of these methods discriminated well between cultivars, but they varied in reproducibility and accuracy. The preferred method was inoculation of unwounded, cold stored plants with a zoospore suspension. It was the least laborious method, and the results were reproducible when the same cultivars were tested several times over several years. Sammendraget er redigert.