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Sökning: WFRF:(Fridell F.)

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1.
  • Kukkonen, J., et al. (författare)
  • Towards a Comprehensive Evaluation of the Environmental and Health Impacts of Shipping Emissions
  • 2022
  • Ingår i: Springer Proceedings in Complexity. - Cham : Springer International Publishing. - 2213-8684 .- 2213-8692. ; , s. 329-336
  • Konferensbidrag (refereegranskat)abstract
    • We present a new concept for marine research, applied in the EU-funded project EMERGE, “Evaluation, control and Mitigation of the EnviRonmental impacts of shippinG Emissions” (2020–2024; https://emerge-h2020.eu/ ). For the first time, both the various marine and atmospheric impacts of the shipping sector have been and will be comprehensively analyzed, using a concerted modelling and measurements framework. The experimental part of the project focuses on five European geographical case studies in different ecologically vulnerable regions, and a mobile onboard case study. The EMERGE consortium has also developed a harmonised and integrated modelling framework to assess the combined impacts of shipping emissions, both (i) on the marine ecosystems and (ii) the atmospheric environment. The first results include substantial refinements of a range of models to be applied, especially those for the STEAM and OpenDrift models. In particular, the STEAM (Ship Traffic Emission Assessment Model) model has been extended to allow for the effects of atmospheric and oceanographic factors on the fuel consumption and emissions of the ships. The OpenDrift model has been improved to take into account the partitioning, degradation, and volatilization of pollutants in water. The predicted emission and discharge values have been used as input for both regional scale atmospheric dispersion models, such as WRF-CMAQ (Weather Research and Forecasting—Community Multiscale Air Quality Model) and SILAM (System for Integrated modeLling of Atmospheric composition), and water quality and circulation models, such as OpenDrift (Open source model for the drifting of substances in the ocean) and Delft3D (oceanographic model). The case study regions are Eastern Mediterranean, Northern Adriatic Sea, the Lagoon of Aveiro, the Solent Strait and the Öresund Strait. We have also conducted a substantial part of the experimental campaigns scheduled in the project. The final assessment will include the benefits and costs of control and mitigation options affecting water quality, air pollution exposure, health impacts, climate forcing, and ecotoxicological effects and bioaccumulation of pollutants in marine biota.
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  • Sundh, Henrik, 1976, et al. (författare)
  • Reduced water quality associated with higher stocking density disturbs the intestinal barrier functions of Atlantic salmon (Salmo salar L.)
  • 2019
  • Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 512
  • Tidskriftsartikel (refereegranskat)abstract
    • The stocking density of fish in aquaculture is of major importance as it may have profound effects on water quality resulting in impact on fish health and possibly affect the external barriers that protect against pathogens There are many husbandry conditions, including stocking density, that may affect the primary protective barriers, i.e. the skin, intestine and gills, against invading pathogens and other harmful substances. It is well known that increased fish density will lead to decreased dissolved oxygen (DO) levels and affect other water quality parameters such as carbon dioxide, pH and ammonia. It is not known if such changes in the rearing environment affect the intestinal primary barriers of Atlantic salmon. Groups of Atlantic salmon post-smolts were kept for 57 days in tanks supplied with seawater at a constant flow at stocking densities of 10, 30, 50 and 70 kg m−3; reduced water quality was associated with higher stocking density. Repeated sampling for plasma cortisol and water cortisol release rate indicate that the highest stocking density elicited a primary stress response in the fish, which decreased with time. The physical intestinal barrier was assessed using paracellular permeability measurements, i.e. transepithelial electrical resistance (TER) and diffusion rate of 14C-mannitol, in combination with the translocation rate of heat-inactivated Aeromonas salmonicida. The physical intestinal barrier decreased with increasing density, both when measured as decreased transepithelial electrical resistance and as elevated paracellular permeability for 14C-mannitol. As this was observed at a time point when no differences could be seen in plasma cortisol or cortisol release rate, it suggests that intestinal paracellular permeability can be a useful marker for chronic stress in salmon. The status of the intestinal immune system was assessed as degree of neutrophil infiltration as well as the mRNA expression of the pro-inflammatory cytokines, interferon γ (IFNγ), interleukin (IL) 1β and tumor necrosis factor (TNF) α, anti-inflammatory cytokines, IL-10 and transforming growth factor β (TGFβ) and other immune related-genes, IL-8 and the inhibitor of the transcription factor nuclear factor κB (IκB). The intestinal immune system was affected at the highest stocking density as observed by a decreased expression of IFNγ in parallel with higher infiltration of neutrophils. In conclusion, high stocking density associated with reduced water quality is chronically stressful to the fish as it elicits a primary stress response as well as a weakened physical and disturbed immunological primary barrier.
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4.
  • Fridell, F, et al. (författare)
  • Effect of hyperoxygenation on the susceptibility of Atlantic salmon (Salmo salar L.) to experimental challenge of IPN virus
  • 2007
  • Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 270:1-4, s. 23-35
  • Tidskriftsartikel (refereegranskat)abstract
    • Intensive salmon smolt production normally includes reduced water flow and hyperoxygenation (added oxygen) of remaining water. There is little information on how different water quality parameters influence the fish health and the susceptibility to infectious diseases. The current experiment was carried out to evaluate if the combination of hyperoxygenation and reduced water flow (hyperoxic) can act as a chronic stressor to salmon in freshwater (FW) in such a way that it increases the susceptibility to IPN virus (IPNV) following seawater transfer. In FW, after 22 days of hyperoxic exposure plasma ion, TBARS and cortisol were measured. The cortisol levels were significantly (p = 0.011) higher in the hyperoxic group compared to controls maintained under normal oxygen saturation and water flow (normoxic), indicating chronic stress. Hyperoxygenation in FW caused decreased plasma [Cl−] compared to the normoxic group (p = 0.037), while [K+] tended to be higher in the hyperoxic group (p = 0.088). No significant differences were observed in plasma [Na+], total osmolality, TBARS or hematocrit, but there was a tendency towards a lower hct in the hyperoxic compared to the normoxic group. In SW the mortality was higher in the hyperoxic group challenged with IPNV (34%) compared to the normoxic group challenged with IPNV (20%) (p = 0.02), and no mortality was observed in the PBS injected fish. The challenged fish showed an overall increase in plasma cortisol day 8, 10, 12 and 14 post-challenge (p = 0.015, p = 0.000, p = 0.046 and p = 0.022 respectively). After SW transfer and challenge, plasma [K+] was elevated in both challenged groups, but no consistent trends were found for plasma [Cl−], [Na+] or total osmolality during the SW phase. There were no significant differences in the gene expression level of IFN 1α, Mx and IL 1β prior to challenge, suggesting that the basic expression level of these genes were not affected by hyperoxygenation. IPNV was detected in kidney and pylorus, by immunohistochemistry, cell culture, and RT-PCR in head kidney. This experiment indicates that chronic stress induced by a combination of low water flow and hyperoxygenation increases the susceptibility to IPNV challenge.
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  • Sundh, Henrik, 1976, et al. (författare)
  • The effect of hyperoxygenation and reduced flow in fresh water and subsequent infectious pancreatic necrosis virus challenge in sea water, on the intestinal barrier integrity in Atlantic salmon, Salmo salar L
  • 2009
  • Ingår i: Journal of Fish Diseases. - 1365-2761. ; 32:8, s. 687-98
  • Tidskriftsartikel (refereegranskat)abstract
    • In high intensive fish production systems, hyperoxygenation and reduced flow are often used to save water and increase the holding capacity. This commonly used husbandry practice has been shown to be stressful to fish and increase mortality after infectious pancreatic necrosis virus (IPNV) challenge, but the cause and effect relationship is not known. Salmonids are particularly sensitive to stress during smoltification and the first weeks after seawater (SW) transfer. This work aimed at investigating the impact of hyperoxygenation combined with reduced flow in fresh water (FW), on the intestinal barrier in FW as well as during later life stages in SW. It further aims at investigating the role of the intestinal barrier during IPNV challenge and possible secondary infections. Hyperoxygenation in FW acted as a stressor as shown by significantly elevated plasma cortisol levels. This stressful husbandry condition tended to increase paracellular permeability (P(app)) as well as translocation of Aeromonas salmonicida in the posterior intestine of Atlantic salmon. After transfer to SW and subsequent IPNV challenge, intestinal permeability, as shown by P(app), and translocation rate of A. salmonicida increased in the anterior intestine, concomitant with further elevation in plasma cortisol levels. In the anterior intestine, four of five fish displayed alterations in intestinal appearance. In two of five fish, IPNV caused massive necrosis with significant loss of cell material and in a further two fish, IPNV caused increased infiltration of lymphocytes into the epithelium and granulocytes in the lamina propria. Hyperoxygenation and reduced flow in the FW stage may serve as stressors with impact mainly during later stages of development. Fish with an early history of hyperoxygenation showed a higher stress response concomitant with a disturbed intestinal barrier function, which may be a cause for the increased susceptibility to IPNV infection and increased susceptibility to secondary infections.
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