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The southern regions of Sweden, Norway and Finland are among the areas in Europe most affected by surface water acidification (European Environment Agency, 2016). Since the 1980s, some steps have been taken to contrast this issue, which have contributed to a steady recovery of the water chemistry (Erlandsson et al., 2010). Among others, the Geneva Convention on Long Range Transboundary Air Pollution and its associated protocols have made an important contribution to the reduction of sulfate emissions (ibid.). In addition, monitoring programs have been put in place to detect patterns of acidification, and predict the long-term path to full recovery (European Environment Agency, 2016; Fölster et al., 2014). A number of models have been developed in order to study the long-term trends in the levels of PH and other acidifying variables of relevance (Moldan et al., 2013; Wright and Cosby, 2003). Those models are useful to evaluate the overall trend in the levels of water acidity, and discuss whether the process of recovery is going in the right direction. However, a limitation of those models is that they might overlook the occurrence of episodic acidification, which can have severe impacts on local ecosystems (Baker et al., 1996; Heard et al., 1997; Laudon, 2008). Sudden changes in the levels of acidity can be deadly to a large number of fish species, and undermine long-term biodiversity (ibid.). The purpose of this research is to contribute to fill this knowledge gap, by developing a framework to analyse, graphically and numerically, trends in the occurrence of episodic acidification. By combining the use of generalised additive models and quantile regression, models able to incorporate both seasonal and long-term time trends are developed. Patterns in episodic acidification are then illustrated with the help of visual tools first introduced by von Brömssen et al. (2021).

Mälarens vattenvårdsförbund, SMHI och Norrvatten har under mer än 50 år (1967-2019) samlat in vattenkemiska och meteorologiska data över ett antal viktiga vattenkvalitetsparametrar. Denna unika långa serie användes i denna rapport för att studera vilka signifikanta förändringar över tid som kan urskiljas, vilka som är de viktigaste drivvariablerna och om data kan användas för att dra slutsatser om Mälarens framtida vattenkvalitet i ett förändrat klimat.

The induction of long-lasting clinical and virological protection is needed for a successful vaccination program against the bovine respiratory syncytial virus (BRSV). In this study, calves with BRSV-specific maternally derived antibodies were vaccinated once, either with (i) a BRSV pre-fusion protein (PreF) and MontanideTM ISA61 VG (ISA61, n = 6), (ii) BRSV lacking the SH gene (ΔSHrBRSV, n = 6), (iii) a commercial vaccine (CV, n = 6), or were injected with ISA61 alone (n = 6). All calves were challenged with BRSV 92 days later and were euthanized 13 days post-infection. Based on clinical, pathological, and proteomic data, all vaccines appeared safe. Compared to the controls, PreF induced the most significant clinical and virological protection post-challenge, followed by ΔSHrBRSV and CV, whereas the protection of PreF-vaccinated calves was correlated with BRSV-specific serum immunoglobulin (Ig)G antibody responses 84 days post-vaccination, and the IgG antibody titers of ΔSHrBRSV- and CV-vaccinated calves did not differ from the controls on this day. Nevertheless, strong anamnestic BRSV- and PreF-specific IgG responses occurred in calves vaccinated with either of the vaccines, following a BRSV challenge. In conclusion, PreF and ΔSHrBRSV are two efficient one-shot candidate vaccines. By inducing a protection for at least three months, they could potentially improve the control of BRSV in calves.

Under året har provtagning utförts en gång i månaden vid 4 stationer i Fyrisån samt i tillflödena Vendelån, Jumkilsån och Sävjaån. Provtagning och analys har utförts av det ackrediterade kemiska laboratoriet vid institutionen för vatten och miljö, SLU (SWEDAC nr 1208) på uppdrag av Fyrisåns vattenförbund. Utöver detta har under sommaren 2020 provtagning för analys av 12 PFAS-substanser och cirka 80 andra organiska mikroföroreningar utförts vid tre av de ordinarie provtagningsstationerna samt vid fyra tillfälliga stationer, se Tabell 1. Dessa prover har analyserats på POPs-laboratoriet, forskningslaboratoriet för organiska miljöföroreningar, vid institutionen för vatten och miljö, SLU. Resultaten bifogas detta nyhetsbrev. Detta nyhetsbrev innehåller en kortfattad sammanfattning av årets analysresultat.

A number of studies have evaluated the effects of forest harvest on mercury (Hg) concentrations and exports in surface waters, but few studies have tested the effect from forest harvest on the change in fish Hg concentrations over the course of several years after harvest. To address this question, mercury (Hg) concentrations in perch (Perca fluviatilis) muscle tissue from five lakes were analyzed for two years before (2010-2011) and three years after (2013-2015) forest harvest conducted in 2012. Fish Hg concentrations in the clear-cut catchments (n = 1373 fish specimens) were related to temporal changes of fish Hg in reference lakes (n = 1099 fish specimen) from 19 lakes in the Swedish National Environmental Monitoring Programme. Small (length < 100 mm) and large perch (length >= 100 mm) were analyzed separately, due to changing feeding habitats of fish over growing size. There was considerable year-to-year and lake-to-lake variation in fish Hg concentrations (-14%-121%) after forest harvest in the clearcut lakes, according to our first statistical model that count for fish Hg changes. While the effect ascribed to forest harvest varied between years, after three years (in 2015), a significant increase of 26% (p < 0.0001) in Hg concentrations of large fish was identified in our second statistical model that pooled all 5 clearcut lakes. The large fish Hg concentrations in the 19 reference lakes also varied, and in 2015 had decreased by 7% (p = 0.03) relative to the concentrations in 2010-2011. The majority of the annual changes in fish Hg concentrations in the clearcut lakes after harvest were in the lower range of earlier predictions for high-latitude lakes extrapolated primarily from the effects of forest harvest operations on Hg concentrations in water. Since the risk of forest harvest impacts on Hg extends to fish and not just surface water concentrations, there is even more reason to consider Hg effects in forestry planning, alongside other ecosystem effects.

Background: Provision of shelter for horses kept on summer pasture is rarely considered in welfare guidelines, perhaps because the benefits of shelter in warm conditions are poorly documented scientifically. For cattle, shade is a valued resource during summer and can mitigate the adverse effects of warm weather on well-being and performance. We found in a previous study that horses utilized shelters frequently in summer. A shelter with a roof and closed on three sides (shelter A) was preferred and can reduce insect pressure whereas a shelter with roof and open on three sides was not utilized. However, shelter A restricts the all-round view of a horse, which may be important for horses as flight animals. Therefore, we studied whether a shelter with roof, where only the upper half of the rear wall was closed (shelter B), would be utilized while maintaining insect protection properties and satisfying the horses' sense for security. A third shelter was offered with walls but no roof (shelter C) to evaluate whether the roof itself is an important feature from the horse's perspective. Eight Warmblood horses were tested each for 2 days, kept individually for 24 h in two paddocks with access to shelters A and B, or shelters A and C, respectively. Shelter use was recorded continuously during the night (1800-2400 h, 0200-0600 h) and the following day (0900-1600 h), and insect defensive behaviour (e.g., tail swish) in instantaneous scan samples at 5-min intervals during daytime.Results: Seven horses used both shelters A and B, but when given the choice between shelters A and C, shelter C was scarcely visited. There was no difference in duration of shelter use between night (105.8 +/- 53.6 min) and day (100.8 +/- 53.8, P = 0.829). Daytime shelter use had a significant effect on insect defensive behaviours (P = 0.027). The probability of performing these behaviours was lowest when horses used shelter A compared to being outside (P = 0.038).Conclusions: Horses only utilized shelters with a roof whilst a shelter with roof and closed on three sides had the best potential to lower insect disturbance during daytime in summer.