Katrine Borgå

• Ruus, Anders; Allan, Ian; Bæk, Kine & Borgå, Katrine (2021). Partitioning of persistent hydrophobic contaminants to different storage lipid classes. Chemosphere.  ISSN 0045-6535.  263 . doi: 10.1016/j.chemosphere.2020.127890 Full text in Research Archive. Show summary

  Lipids generally represent the major matrix contributing to the absorptive capacity for hydrophobic organic contaminants in aquatic ecosystems. The aim of the present study was to determine whether contaminants partition to a different degree to the different storage lipid classes: wax ester (WE) and triacylglycerol (TAG). This was undertaken by studying experimentally the partitioning of organochlorine compounds between lipids (WE or TAG) and silicone rubber phase. Our results indicate that hydrophobic compounds have a slightly higher affinity for WE than for TAG. The findings thus corroborate earlier suggestions that contaminants accumulate to a greater extent in food webs with a higher reliance of on WE, such as in the Arctic. This knowledge is of interest since it implies that possible changes in planktonic community species composition, and thereby possible changes in the lipid composition, may have consequences for accumulation of hydrophobic contaminants in apex predators. However, the magnitude of these consequences remains unknown, and there may well be other factors of importance for previously observed higher accumulation of contaminants in Arctic systems. Thus, we have here identified aspects regarding partitioning of contaminants to lipids that need further scrutiny, and there is a need for further quantitative estimates of the suggested difference in absorptive capacities for hydrophobic contaminants between WE and TAG.

• Andvik, Clare; Jourdain, Eve; Ruus, Anders; Lyche, Jan Ludvig; Karoliussen, Richard & Borgå, Katrine (2020). Preying on seals pushes killer whales from Norway above pollution effects thresholds. Scientific Reports.  ISSN 2045-2322.  10 . doi: 10.1038/s41598-020-68659-y Full text in Research Archive. Show summary

  Killer whales (Orcinus orca) are at risk from high levels of biomagnifying pollutants, such as polychlorinated biphenyls (PCBs) and mercury (Hg). Previous toxicological risk assessments for the Norwegian killer whale population have assumed fish as the primary prey source, and assessed the population as below established effect thresholds. However, some individuals have recently been identified to also feed on seals. This study is the first to quantify levels of pollutants in seal-eating killer whales from northern Norway, and to measure Hg levels in the skin of killer whales worldwide. We found higher levels of all pollutants in seal-eating than fish-eating killer whales, including the emerging brominated flame retardants pentabromoethylbenzene (PBEB), pentabromotoluene (PBT) and hexabromobenzene (HBB). Sum polychlorinated biphenyls (ΣPCBs) in the blubber of seal-eaters (n = 7, geometric mean = 46 µg/g l.w.) were four times higher than fish-eaters (n = 24, geometric mean = 11 µg/g l.w.), which pushed all seal-eating individuals above multiple thresholds for health effects. Total Hg levels in skin of seal-eaters (n = 10, arithmetic mean = 3.7 µg/g d.w.) were twice as high as in fish-eaters (n = 28, arithmetic mean = 1.8 µg/g d.w.). Our results indicate that by feeding on higher trophic prey, the Norwegian killer whale population is at higher risk of health effects from pollution than previously assumed.

• Jourdain, Eve; Andvik, Clare Margaret; Karoliussen, Richard; Ruus, Anders; Vongraven, Dag & Borgå, Katrine (2020). Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway. Ecology and Evolution.  ISSN 2045-7758.  10(9), s 4115- 4127 . doi: 10.1002/ece3.6182 Full text in Research Archive. Show summary

  Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017–2018 in northern Norway using stable isotopic nitrogen (δ15N: 15N/14N) and carbon (δ13C: 13C/12C) ratios. A Gaussian mixture model assigned sampled individuals to three differentiated clusters, characterized by disparate nonoverlapping isotopic niches, that were consistent with predatory field observations: seal‐eaters, herring‐eaters, and lumpfish‐eaters. Seal‐eaters showed higher δ15N values (mean ± SD: 12.6 ± 0.3‰, range = 12.3–13.2‰, n = 10) compared to herring‐eaters (mean ± SD: 11.7 ± 0.2‰, range = 11.4–11.9‰, n = 19) and lumpfish‐eaters (mean ± SD: 11.6 ± 0.2‰, range = 11.3–11.9, n = 9). Elevated δ15N values for seal‐eaters, regardless of sampling season, confirmed feeding at high trophic levels throughout the year. However, a wide isotopic niche and low measured δ15N values in the seal‐eaters, compared to that of whales that would eat solely seals (δN‐measured = 12.6 vs. δN‐expected = 15.5), indicated a diverse diet that includes both fish and mammal prey. A narrow niche for killer whales sampled at herring and lumpfish seasonal grounds supported seasonal prey specialization reflective of local peaks in prey abundance for the two fish‐eating groups. Our results, thus, show differences in prey specialization within this killer whale population in Norway and that the episodic observations of killer whales feeding on prey other than fish are a consistent behavior, as reflected in different isotopic niches between seal and fish‐eating individuals.

• Lode, Torben; Heuschele, Jan David; Andersen, Tom; Titelman, Josefin; Hylland, Ketil & Borgå, Katrine (2020). Contrasting Effects of Predation Risk and Copper on Copepod Respiration Rates. Environmental Toxicology and Chemistry.  ISSN 0730-7268.  39(9), s 1765- 1773 . doi: 10.1002/etc.4804
• Mazzoni, Michela; Ferrario, Claudia; Bettinetti, Roberta; Piscia, Roberta; Cicala, Davide; Volta, Pietro; Borgå, Katrine; Valsecchi, Sara & Polesello, Stefano (2020). Trophic Magnification of Legacy (PCB, DDT and Hg) and Emerging Pollutants (PFAS) in the Fish Community of a Small Protected Southern Alpine Lake (Lake Mergozzo, Northern Italy). Water.  ISSN 2073-4441.  12, s 1- 17 . doi: 10.3390/w12061591
• Sengupta, Sagnik; Leinaas, Hans Petter; van Gestel, Cornelis A.M.; Rundberget, Jan Thomas & Borgå, Katrine (2020). A multiple life history trait-based and time-resolved assessment of imidacloprid effects and recovery in the widely distributed collembolan Folsomia quadrioculata. Environmental Toxicology and Chemistry.  ISSN 0730-7268. . doi: 10.1002/etc.4897 Show summary

  Life history traits determine individual fitness and the fate of populations. Imidacloprid, a widely used neonicotinoid insecticide, which persists in soil for more than 100 d at biologically relevant levels, may affect non‐target and ecologically important species, such as collembolans. In the present study, we determined the sublethal effects of short‐term imidacloprid exposure and post‐exposure recovery in the collembolan Folsomia quadrioculata, which occurs abundantly across the northern hemisphere. We assessed survival, egg production, and hatching success in adult springtails exposed for 14 d through the diet to imidacloprid followed by a 28 d post‐exposure phase. Survival and hatching success were high throughout the experiment in all the treatments, with no clear concentration dependency. However, egg production declined during the exposure phase and nearly stopped between 8 and 14 d in all the treatments (except the control), but resumed during the post‐exposure phase. Moreover, the resumption of egg production showed a concentration‐dependent delay. Our findings suggest that low imidacloprid exposures can restrict reproduction, with potentially severe consequences for the population, notwithstanding the partial recovery in egg production.

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• Giebichenstein, Julia; Gopakumar, Anjali; Varpe, Øystein; Andersen, Tom; Gabrielsen, Geir W. & Borgå, Katrine (2020). Seasonal Variation of Mercury in an Arctic Marine Food Web.
• Konestabo, Heidi Sjursen; Birkemoe, Tone; Leinaas, Hans Petter; van Gestel, Cornelis A.M. & Borgå, Katrine (2020). How does a widely used neonicotinoid affect the soil fauna under natural field conditions?.
• Ruus, Anders; Bæk, Kine; Rundberget, Thomas; Allan, Ian; Beylich, Bjørnar; Vogelsang, Christian; Schlabach, Martin; Götsch, Arntraut; Borgå, Katrine & Helberg, Morten (2020). Environmental Contaminants in an Urban Fjord, 2019. NIVA-rapport. 7555. Full text in Research Archive. Show summary

  This programme, “Environmental Contaminants in an Urban Fjord” has covered sampling and analyses of sediment and organisms in a marine food web of the Inner Oslofjord, in addition to samples of blood and eggs from herring gull. The programme also included inputs of pollutants via surface water (storm water), and effluent water and sludge from a sewage treatment plant. The bioaccumulation potential of the contaminants in the Oslo fjord food web was evaluated. The exposure to/accumulation of the contaminants was also assessed in birds. A vast number of chemical parameters have been quantified, in addition to some biological effect parameters in cod, and the report serves as a status description of the concentrations of these chemicals in different compartments of the Inner Oslofjord marine ecosystem.

• Thorstensen, H. S.; Ruus, Anders; Helberg, Morten; Bæk, Kine; Enge, Ellen Katrin & Borgå, Katrine (2020). Herring gull and common eider as indicators of contaminants in an urban fjord.

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