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Tidskriftsartikel (refereegranskat)
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- Halbach, Laura, et al.
(författare)
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Tidewater Glaciers and Bedrock Characteristics Control the Phytoplankton Growth Environment in a Fjord in the Arctic
- 2019
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Meltwater discharge from tidewater glaciers impacts the adjacent marine environment. Due to the global warming, tidewater glaciers are retreating and will eventually terminate on land. Yet, the mechanisms through which meltwater runoff and subglacial discharge from tidewater glaciers influence marine primary production remain poorly understood, as data in close proximity to glacier fronts are scarce. Here, we show that subglacial meltwater discharge and bedrock characteristics of the catchments control the phytoplankton growth environment inside the fjord, based on data collected in close proximity to tidewater glacier fronts in Kongsfjorden, Svalbard from 26 to 31 July 2017. In the southern part of the inner fjord, glacial meltwater from subglacial discharge was rich in fine sediments derived from erosion of Devonian Old Red Sandstone and carbonate rock deposits, limiting light availability for phytoplankton (0.6 mg m(-3) Chl a on average, range 0.2-1.9 mg m(-3)). In contrast, coarser sediments derived from gneiss and granite bedrock and lower subglacial discharge rates were associated with more favourable light conditions facilitating a local phytoplankton bloom in the northern part of the inner fjord with mean Chl a concentration of 2.8 mg m(-3) (range 1.3-7.4 mg m(-3)). In the northern part, glacier meltwater was a direct source of silicic acid through weathering of the silica-rich gneiss and granite bedrock. Upwelling of the subglacial freshwater discharge plume at the Kronebreen glacier front in the southern part entrained large volumes of ambient, nutrient-rich bottom waters which led to elevated surface concentrations of ammonium, nitrate, and partly silicic acid. Total dissolved inorganic nitrogen transported to the surface with the upwelling of the subglacial discharge plume has a significant potential to enhance summer primary production in Kongsfjorden, with ammonium released from the seafloor being of particular importance. The transition from tidewater to land-terminating glaciers may, thus, reduce the input of nutrients to the surface layer with negative consequences for summer productivity.
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- Andren, P, et al.
(författare)
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Therapist-guided and parent-guided internet-delivered behaviour therapy for paediatric Tourette's disorder: a pilot randomised controlled trial with long-term follow-up
- 2019
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 9:2, s. e024685-
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Tidskriftsartikel (refereegranskat)abstract
- Behaviour therapy (BT) for Tourette’s disorder (TD) and persistent (chronic) motor or vocal tic disorder (PTD) is rarely available. We evaluated the feasibility of adapting two existing BT protocols for TD/PTD (habit reversal training (HRT) and exposure and response prevention (ERP)) into a therapist-guided and parent-guided online self-help format.DesignA pilot, single-blind, parallel group randomised controlled trial.SettingA specialist outpatient clinic in Sweden.ParticipantsTwenty-three young people with TD/PTD, aged 8–16.InterventionsTwo 10-week therapist-guided and parent-guided internet-delivered programmes (called BIP TIC HRT and BIP TIC ERP).OutcomeThe primary outcome measure was the Yale Global Tic Severity Scale. Blinded evaluators rated symptoms at baseline, post-treatment and 3-month follow-up (primary endpoint). All participants were naturalistically followed up to 12 months after treatment.ResultsPatients and parents rated the interventions as highly acceptable, credible and satisfactory. While both interventions resulted in reduced tic-related impairment, parent-rated tic severity and improved quality of life, only BIP TIC ERP resulted in a significant improvement on the primary outcome measure. Within-group effect sizes and responder rates were, respectively: d=1.12 and 75% for BIP TIC ERP, and d=0.50 and 55% for BIP TIC HRT. The therapeutic gains were maintained up to 12 months after the end of the treatment. Adverse events were rare in both groups. The average therapist support time was around 25 min per participant per week.ConclusionsInternet-delivered BT has the potential to greatly increase access to evidence-based treatment for young people with TD/PTD. Further evaluation of the efficacy and cost-effectiveness of this treatment modality is warranted.Trial registration numberNCT02864589; Pre-results.
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- Klimkowska, Agata, et al.
(författare)
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Are we restoring functional fens? : The outcomes of restoration projects in fens re-analysed with plant functional traits
- 2019
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- In peatland restoration we often lack an information whether re-established ecosystems are functionally similar to non-degraded ones. We re-analysed the long-term outcomes of restoration on vegetation and plant functional traits in 38 European fens restored by rewetting (18 sites) and topsoil removal (20 sites). We used traits related to nutrient acquisition strategies, competitiveness, seed traits, and used single- and multi-trait metrics. A separate set of vegetation records from near-natural fens with diverse plant communities was used to generate reference values to aid the comparisons. We found that both restoration methods enhanced the similarity of species composition to non-degraded systems but trait analysis revealed differences between the two approaches. Traits linked to nutrient acquisition strategies indicated that topsoil removal was more effective than rewetting. After topsoil removal competitive species in plant communities had decreased, while stress-tolerant species had increased. A substantial reduction in nutrient availability ruled out the effect of initial disturbance. An ability to survive and grow in anoxic conditions was enhanced after restoration, but the reference values were not achieved. Rewetting was more effective than topsoil removal in restricting variation in traits values permitted in re-developing vegetation. We found no indication of a shift towards reference in seed traits, which suggested that dispersal constraint and colonization deficit can be a widespread phenomena. Two functional diversity indices: functional richness and functional dispersion showed response to restoration and shifted values towards reference mires and away from the degraded systems. We concluded that targeting only one type of environmental stressor does not lead to a recovery of fens, as it provides insufficient level of stress to restore a functional ecosystem. In general, restoration efforts do not ensure the re-establishment and long-term persistence of fens. Restoration efforts result in recovery of fen ecosystems, confirmed with our functional trait analysis, although more rigid actions are needed for restoring fully functional mires, by achieving high and constant levels of anoxia and nutrient stresses.
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