Bustnes J.O.,Norwegian Institute for Nature Research |
Bangjord G.,Norwegian Environment Agency |
Ahrens L.,Swedish University of Agricultural Sciences |
Herzke D.,Norwegian Institute For Air Research |
And 2 more authors.
Environmental Toxicology and Chemistry | Year: 2015
Accumulation of persistent organic pollutants (POPs) in wildlife may be influenced by the physical and biotic environment, and concentrations vary greatly among areas, seasons, and individuals. Different hypotheses about sources of variation in perfluoroalkyl substance (PFAS) concentrations were examined in eggs (n=107) of tawny owls (Strix aluco) collected over a 24-yr period (1986-2009) in Norway. Predictor variables included the North Atlantic Oscillation (NAO), temperature, snow, food availability (vole abundance), and individual traits such as age, body condition, and clutch size. Concentrations of both perfluoro-octane sulfonate (PFOS) and perfluoroalkyl carboxylates (PFCAs) varied several fold in the population, both inter- and intra-annually. Moreover, individuals laid eggs with several times higher or lower PFAS concentrations within few years (1 yr-5 yr). After controlling for temporal trends (i.e., declining PFOS and increasing PFCA concentrations), both PFOS and PFCAs were positively associated to the winter NAO in the previous year (NAOy - 1), suggesting that atmospheric transport may be affecting the input of PFASs to the local ecosystem. Perfluoro-octane sulfonate was negatively related to temperature, but the pattern was complex as there was an interaction between temperature and the feeding conditions. The PFOS accumulation was highest in years with high vole abundance and low to medium temperatures. For PFCAs, there was an interaction between NAOy - 1 and feeding conditions, suggesting that strong air transport toward Norway and high consumption of voles led to a moderate increase in PFCA accumulation. The individual traits, however, had very little impact on the concentrations of PFASs in the eggs. The present study thus suggests that annual variation in environmental conditions influences the concentrations of PFASs in a terrestrial raptor such as the tawny owl. © 2014 SETAC. Source
Brooks S.J.,Norwegian Institute for Water Research |
Farmen E.,Norwegian Institute for Water Research |
Farmen E.,Norwegian Environment Agency |
Heier L.S.,Norwegian University of Life Sciences |
And 2 more authors.
Aquatic Toxicology | Year: 2015
Mytilus species are important organisms in marine systems being highly abundant and widely distributed along the coast of Europe and worldwide. They are typically used in biological effects studies and have a suite of biological effects endpoints that are frequently measured and evaluated for stress effects in laboratory experiments and field monitoring programmes. Differences in bioaccumulation and biological responses of the three Mytilus species following exposure to copper (Cu) were investigated. A laboratory controlled exposure study was performed with three genetically confirmed Mytilus species; M. galloprovincialis, M. edulis and M. trossulus. Chemical bioaccumulation and biomarkers were assessed in all three Mytilus species following a 4 day and a 21 day exposure to waterborne copper concentrations (0, 10, 100 and 500. μg/L). Differences in copper bioaccumulation were measured after both 4 and 21 days, which suggests some physiological differences between the species. Furthermore, differences in response for some of the biological effects endpoints were also found to occur following exposure. These differences were discussed in relation to either real physiological differences between the species or merely confounding factors relating to the species natural habitat and seasonal cycles. Overall the study demonstrated that differences in chemical bioaccumulation and biomarker responses between the Mytilus spp. occur with potential consequences for mussel exposure studies and biological effects monitoring programmes. Consequently, the study highlights the importance of identifying the correct species when using Mytilus in biological effects studies. © 2014 Elsevier B.V. Source
Holmern T.,Norwegian University of Science and Technology |
Holmern T.,Norwegian Environment Agency |
Roskaft E.,Norwegian University of Science and Technology
African Journal of Ecology | Year: 2014
Improving the understanding of human-carnivore conflicts is fundamental for the effective management of interventions. However, earlier research has largely focused on conflicts caused by top carnivores, and there is a general lack of knowledge about the drivers behind conflicts caused by smaller carnivores. Here, we investigated the characteristics and spatial patterns of perceived predators that caused losses of poultry. We used a structured interview of 481 households across seven villages outside Serengeti National Park, Tanzania. Most households kept poultry and livestock, and 48.4% of all households perceived to have lost poultry to predators, but it was unrelated to perceived livestock depredation. On average, predators killed almost one-third of the poultry kept by each household, which is equivalent to an average annual economic loss of US $14.5 ± 18.6, or 10.4% of the cash income. Economic dependency did not influence the likelihood of perceiving depredation. The most parsimonious linear mixed-effects model showed that the probability of claiming losses to predators increased with increasing flock sizes and distance to the nearest protected area. We discuss our findings in relation to the current interest in rural poultry production shown by conservation programmes in Africa. © 2013 John Wiley & Sons Ltd. Source
Olsen S.A.,Norwegian Institute of Marine Research |
Hansen P.K.,Norwegian Institute of Marine Research |
Givskud H.,Norwegian Institute of Marine Research |
Givskud H.,Norwegian Environment Agency |
And 3 more authors.
Aquaculture | Year: 2015
The aquaculture industry supplies coastal waters with large amounts of particulate organic material from the fish cages, which is a source of food for several pelagic and benthic invertebrates and fish. Particularly gadoids, such as cod (Gadus morhua) and saithe (Pollachius virens), are known to aggregate at fish farms in boreal areas. As a step on the way to investigate the influence of organic fish farm waste on wild fish, we conducted a diet-switch study to determine the extent to which fatty acid composition and stable isotopes (δ13C and δ15N) of various tissues could be used to trace diet alterations in cod. Initial analysis of the feeds showed that δ13C results were non-significant and this tracer was not further pursued. Groups of cultivated cod fry (125-200g) were fed either salmon feed, herring fillet or cod feed as control feed and sampling was conducted after 26, 41, 69, 106 and 121days. Fatty acids and stable isotope δ15N were analyzed in the various diets and muscle tissue, and δ15N was determined in the plasma, liver and heart. All fish groups displayed the fatty acid composition of their diets. The salmon feed group had a significant increase of FAs 18:2n6, 18:3n3 and 18:1n9 by the third sampling (day 69). These FAs are found in rich concentrations in vegetable oils used in salmon feed production. The δ15N values showed no significant change in the salmon feed group throughout the experiment whereas the herring group had an increase in all tissues. Linear Discriminant Analysis (LDA) sample distribution plots were identical when FA alone and in combination with the δ15N values were analyzed, and both tests correctly classified more than 96% of the samples. Muscle fatty acids were a more precise tracer than δ15N since specific FAs could be traced and a combination of fatty acid and stable nitrogen analyses did not improve the robustness of the result. © 2014 Elsevier B.V. Source
More than 300 wild reindeer were killed by a lighting strike in central Norway, according to the Norwegian Environment Agency. During the weekend, the agency released startling images showing a mass of reindeer carcasses scattered across a small area on the Hardangervidda mountain plateau. The incident, while rare, is not without precedent in other parts of the world, where lightning bolts have killed large numbers of cattle, elk and other animals that were clustered together during a thunderstorm. SEE ALSO: Heat wave-related anthrax outbreak in Siberia kills young boy, thousands of reindeer The agency says 323 animals were killed, including 70 calves, in the lightning storm on Friday. This area is home to about 2,000 reindeer at this time of the year, the agency said. Agency spokesman Kjartan Knutsen told The Associated Press it's not uncommon for reindeer or other wildlife to be killed by lightning strikes but this was an unusually deadly event. "We have not heard about such numbers before," he said Monday. He said reindeer tend to stay very close to each other in bad weather, which could explain how so many were killed at once. "I don't know if there were several lighting strikes," he said. "But it happened in one moment." Knutsen said the agency is now discussing what to do with the dead animals. Normally, they are just left where they are to let nature take its course, he said. Thousands of reindeer migrate across the barren Hardangervidda plateau as the seasons change. In the U.S., cattle, elk and other animals are far more likely to die from lightning than people are. In May of this year, lightning killed 21 cattle in South Dakota that were feeding around a metal feeding trough during a thunderstorm. In that case, lightning's current of electricity traveled through the trough, into the cattle, and also into the ground. In the Norwegian incident, it's possible the electrical current from a single bolt, or multiple bolts, proved fatal because the animals were in contact with one another, enabling the electrical current to travel through multiple animals. According to the National Oceanic and Atmospheric Administration (NOAA), 32 people have been killed by lightning in the U.S. so far this year.