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| 3. |
- Larsson, Per, et al.
(författare)
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An attempt to measure the flow of chlorinated hydrocarbons, such as PCBs, from water to air in the field
- 1987
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 44:3, s. 219-225
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Tidskriftsartikel (refereegranskat)abstract
- A field sampling device to study the transport of aromatic, persistent chlorinated hydrocarbons from water to air was constructed. It was tested in large, outdoor artificial ponds contaminated with polychlorinated biphenyls (PCBs). The PCB compounds volatilised to air at a rate of 0·9 to 9·6 ng m−2 h−1 depending on levels of PCBs in the water and water temperature.
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| 4. |
- Larsson, Per, et al.
(författare)
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Atmospheric transport of chlorinated hydrocarbons to Sweden 1985 compared to 1973
- 1989
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844 .- 0004-6981. ; 23:8, s. 1699-1711
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Tidskriftsartikel (refereegranskat)abstract
- The atmospheric fallout of DDT and DDE (ΣDDT) over Sweden has decreased during the last decade. Today long-range transport from southern sources outside the country dominates the inflow. This was reflected in a decreasing south-to-north gradient of the compounds in atmospheric deposition and in the lower atomosphere. The fallout of PCBs was similar in 1984–1985 and 1972–1973, and today local contamination by combustion is more prominent than it was 10 years ago, even though PCB restrictions have been in force during the interim. Since PCB deposition is higher in the coastal areas than in the inland regions, other sources, such as volatilization from the seas and long-range transport also contribute to PCBs in fallout. The levels of PCB and ΣDDT in the lower atmosphere were positively correlated with temperature. Consequently, the compounds tended to be in the gas phase during the warmer summer period whereas during winter they were more liable to be adsorbed to particles, partition to airborne water and contribute in fallout. From each sampling station a chromatographic 'fingerprint' of pollutants in airborne fallout and in the lower atmosphere was obtained. The fingerprint was the combined result of the station's location and climate. The results show that considerable amounts of chlorinated pollutants are being transported to and within Sweden via the atmosphere.
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| 5. |
- Larsson, Per, et al.
(författare)
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Microbial degradation of xenobiotic, aromatic pollutants in humic water
- 1988
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 54:7, s. 1864-1867
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Tidskriftsartikel (refereegranskat)abstract
- The microbial degradation of a number of 14C-labeled, recalcitrant,aromatic pollutants, including trichloroguaiacol and di-, tri-,and pentachlorophenol, was investigated in aquatic model systemsin the laboratory. Natural, mixed cultures of microorganismsin the water from a brown-water lake with a high content ofhumic compounds mineralized all of the tested substances toa higher degree than did microorganisms in the water from aclear-water lake. Dichlorophenol was the most rapidly degradedpollutant.
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| 6. |
- Okla, Lennart, et al.
(författare)
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Day-night differences in volatilization rates of polychlorinated biphenyls from water to to air
- 1987
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 6:9, s. 659-662
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Tidskriftsartikel (refereegranskat)abstract
- The transport rate of polychlorinated biphenyls (PCBs) from water to air was followed in a large (50-m3) artificial pond. The transport rate across the water/air interface during the day exceeded the rate at night and was positively correlated to air temperature. Volatilization is probably responsible for the PCB transfer.
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| 7. |
- Weich, R G, et al.
(författare)
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Extracellular alkaline phosphatase activity in Ulva lactuca L
- 1989
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981 .- 1879-1697. ; 129:1, s. 33-44
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular alkaline phosphatase activity (APA) was detected in the marine macroalga Ulva lactuca, cultivated in laboratory conditions under phosphate limitation. Algal discs were grown in continuous light and in darkness for a maximum of 205 h in sterilized seawater supplied with ammonium nitrate and various phosphate concentrations. APA and phosphate uptake in U. lactuca was stimulated in light whereas inhibition was detected in darkness. APA increased significantly during the cultivation in a phosphate-deficient medium but was suppressed at high external phosphate concentrations. In addition, pretreatment in penicillin over 48 h markedly enhanced enzyme activity during P limitation. The pretreatment in penicillin reduced the number of surface-associated bacteria. Our results indicate that APA in U. lactuca was dependent on the external phosphate concentration, energy from photophosphorylation and bacteria. Since intracellular polyphosphates and an orthophosphate pool still were displayed in 31P NMR spectra after cultivation at phosphate-limiting conditions, P deficiency was not suggested. Unfortunately, NMR spectra reflect total amounts of P compounds and local differences in the P status of the multicellular tissue could not be distinguished. Postulating a negative correlation between the P status and APA, a lower P status in meristematic areas during P limitation was suggested. Alkalisation of the growth medium during algal growth in light, and/or intracellular pH changes may additionally have affected enzyme production.
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| 9. |
- Alatalo, Rauno V., et al.
(författare)
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Exploitation competition influences the use of foraging sites by tits : Experimental evidence
- 1987
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Ingår i: Ecology. - : Ecological Society of America. - 0012-9658 .- 1939-9170. ; 68:2, s. 284-290
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Tidskriftsartikel (refereegranskat)abstract
- In coniferous forests of central Sweden, tits (Paridae) and the Goldcrest, Regulus regulus, exploit nonrenewable resources in their group territories during winter. The smaller and socially subordinate species, the Goldcrest and the Coal Tit, Parus ater, forage on the outermost tree parts, while the larger and dominant Willow Tit, Parus montanus, and Crested Tit, Parus cristatus, forage on the inner tree parts. We removed Coal Tits and Goldcrests in three flocks in early winter to see if their absence would cause changes in the foraging patterns of the two dominant species. In late winter, Crested Tits foraged farther outward on branches of spruce in experimental flocks than they did in the control flocks. In spruce, Willow Tits foraged nearer the trunk than Crested Tits, and they did not respond to the experiment. In pine, Willow Tits, however, did move from branches to twigs in the absence of Coal Tits and Goldcrests. The experiment indicates that exploitation competition directly based on food depletion, without any interference, may influence the use of foraging sites by tits in coniferous forests.
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| 10. |
- Cederlund, Göran, et al.
(författare)
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Summer movements of female moose and dispersal of their offspring
- 1987
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Ingår i: Journal of Wildlife Management. - : John Wiley & Sons. - 0022-541X .- 1937-2817. ; 51:2, s. 342-352
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Tidskriftsartikel (refereegranskat)abstract
- Fifty-seven radio-equipped moose (Alces alces) in central Sweden were located during the 3 summers of 1980-83. Forty-two were cows (≤2 years old) and 15 were calves (5 males and 10 females) when captured. Aerial tracking was conducted ≤1 time/week. No significant differences in average size of summer home ranges were found between age classes. All cows returned to the same summer range each spring. Consecutive summer home ranges overlapped from 1 to 100%. Ten of 14 radio-equipped calves accompanied their cow to summer ranges. The 1st indications of separation between cow and offspring were recorded from 7 to 29 May. The average straight line distance between cow and offspring successively increased from separation to mid-June when it became relatively constant (1.5-2.0 km). One of 10 calves that completed the migration together with the cow abandoned its mother's home range completely. Adult female offspring continued to reside near their yearling home range during consecutive summers.
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