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Träfflista för sökning "FÖRF:(Ola Svensson) ;lar1:(su)"

Search: FÖRF:(Ola Svensson) > Stockholm University

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1.
  • Andersson, Marica, et al. (author)
  • Increased noise levels cause behavioural and distributional changes in Atlantic cod and saithe in a large public aquarium—A case study
  • 2023
  • In: Aquaculture, Fish and Fisheries. - : John Wiley & Sons. - 2693-8847.
  • Journal article (peer-reviewed)abstract
    • Abstract Investigating the effects of underwater noise on aquatic animals is a research field that is receiving rapidly increasing attention. Despite this, surprisingly few studies have addressed the potential impacts of noise in a marine animal husbandry setting. In this regard, the behaviour of fish in public aquariums can be used as an indicator of well-being, and noise is known to cause behavioural changes. This case study investigates the behaviour of cod (Gadus morhua) and saithe (Pollachius virens) in a large public aquarium when exposed to increased noise levels originating from an aquarium renovation carried out by construction divers. Swimming behaviour, group formation and vertical distribution, along with yawning and scratching frequencies of the fish, were analysed from video recordings made before, during and after the exposure to increased noise levels. The same parameters were also analysed to evaluate potential effects of the presence of divers when not making renovation noise, compared to fish behaviour prior to the renovation. There was a slight change in the depth distribution of both species and a decrease in the number of scratches in cod due to the presence of divers that were not making renovation noise. In the presence of construction noises in the tank, however, both cod and saithe showed a wider array of behavioural changes, including increased swimming speed, changes in depth distribution and increased yawning frequencies. The results from this case study demonstrate that an underwater renovation with increased noise levels impacts fish behaviour and suggests that underwater noise should be considered during the management of aquatic environments, including public aquaria.
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2.
  • Hentati-Sundberg, J, et al. (author)
  • Fueling of a marine-terrestrial ecosystem by a major seabird colony.
  • 2020
  • In: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10
  • Journal article (peer-reviewed)abstract
    • Seabirds redistribute nutrients between different ecosystem compartments and over vast geographical areas. This nutrient transfer may impact both local ecosystems on seabird breeding islands and regional biogeochemical cycling, but these processes are seldom considered in local conservation plans or biogeochemical models. The island of Stora Karlsö in the Baltic Sea hosts the largest concentration of piscivorous seabirds in the region, and also hosts a large colony of insectivorous House martins Delichon urbicum adjacent to the breeding seabirds. We show that a previously reported unusually high insectivore abundance was explained by large amounts of chironomids-highly enriched in δ15N-that feed on seabird residues as larvae along rocky shores to eventually emerge as flying adults. Benthic ammonium and phosphate fluxes were up to 163% and 153% higher close to the colony (1,300 m distance) than further away (2,700 m) and the estimated nutrient release from the seabirds at were in the same order of magnitude as the loads from the largest waste-water treatment plants in the region. The trophic cascade impacting insectivorous passerines and the substantial redistribution of nutrients suggest that seabird nutrient transfer should be increasingly considered in local conservation plans and regional nutrient cycling models.
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3.
  • Danielsson, Åsa, et al. (author)
  • Effects of re-oxygenation and bioturbation by the polychaete Marenzelleria arctia on phosphorus, iron and manganese dynamics in Baltic Sea sediments
  • 2018
  • In: Boreal environment research. - : FINNISH ENVIRONMENT INST. - 1239-6095 .- 1797-2469. ; 23, s. 15-28
  • Journal article (peer-reviewed)abstract
    • Sediments underlying hypoxic or anoxic water bodies constitute a net source of phosphorus to the bottom water. This source has the potential to enhance eutrophication. Benthic fluxes of dissolved phosphorus, iron and manganese were measured from hypoxic, normoxic, and normoxic bioturbated by the invasive polychaete Marenzelleria arctia sediment in a mesocosm experiment. The highest benthic phosphorus efflux was detected in mesocosms with the hypoxic treatment. Normoxic, bioturbated sediments led to weaker retention of phosphorus compared to oxic, defaunated sediments. Both iron and manganese fluxes increased under bioturbated conditions compared to defaunated sediments. This study shows that re-oxygenation of previously anoxic coastal sediments enhance phosphorus retention in the sediments. Colonisation by M. arctia induce strong mobilisation of iron and manganese due to its intense bioirrigation, which facilitates organic matter degradation and decreases the phosphorus retention by metal oxides in sediment.
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4.
  • Sanderson Bellamy, Angelina, et al. (author)
  • Insect community composition and functional roles along a tropical agricultural production gradient
  • 2018
  • In: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 25:14, s. 13426-13438
  • Journal article (peer-reviewed)abstract
    • High intensity agricultural production systems are problematic not only for human health and the surrounding environment, but can threaten the provision of ecosystem services on which farm productivity depends. This research investigates the effects of management practices in Costa Rica on on-farm insect diversity, using three different types of banana farm management systems: high-input conventional system, low-input conventional system, and organic system. Insect sampling was done using pitfall and yellow bowl traps, left for a 24-h period at two locations inside the banana farm, at the edge of the farm, and in adjacent forest. All 39,091 individual insects were classified to family level and then morphospecies. Insect species community composition and diversity were compared using multivariate statistics with ordination analysis and Monte Carlo permutation testing, and revealed that each of the management systems were significantly different from each other for both trap types. Insect diversity decreased as management intensity increased. Reduced insect diversity resulted in fewer functional groups and fewer insect families assuming different functions essential to ecosystem health. Organic farms had similar species composition on the farm compared to adjacent forest sites, whereas species composition increasingly differed between farm and forest sites as management intensity increased. We conclude that while organic production has minimal impact on insect biodiversity, even small reductions in management intensity can have a significantly positive impact on on-farm insect biodiversity and functional roles supported.
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5.
  • Svensson, Ola, et al. (author)
  • Assessing the ecological impact of banana farms on water quality using aquatic macroinvertebrate community composition
  • 2018
  • In: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 25:14, s. 13373-13381
  • Journal article (peer-reviewed)abstract
    • In Costa Rica, considerable effort goes to conservation and protection of biodiversity, while at the same time agricultural pesticide use is among the highest in the world. Several protected areas, some being wetlands or marine reserves, are situated downstream large-scale banana farms, with an average of 57 pesticide applications per year. The banana industry is increasingly aware of the need to reduce their negative environmental impact, but few ecological field studies have been made to evaluate the efficiency of proposed mitigation strategies. This study compared the composition of benthic macroinvertebrate communities up- and downstream effluent water from banana farms in order to assess whether benthic invertebrate community structure can be used to detect environmental impact of banana fanning, and thereby usable to assess improvements in management practises. Aquatic invertebrate samples were collected at 13 sites, using kick-net sampling. both up- and downstream banana farms in fast flowing streams in the Caribbean zone of Costa Rica. In total, 2888 invertebrate specimens were collected, belonging to 15 orders and 48 families or taxa. The change in community composition was analysed using multivariate statistics. Additionally, a biodiversity index and the Biological Monitoring Working Party (BMWP) score system was applied along with a number of community composition descriptors. Multivariate analyses indicated that surface waters immediately up- and downstream large-scale banana farms have different macroinvertebrate community compositions with the most evident differences being higher dominance by a single taxa and a much higher total abundance, mostly of that same taxon. Assessment of macroinvertebrate community composition thus appears to be a viable approach to detect negative impact from chemical-intensive agriculture and could become an effective means to monitor the efficacy of changes/proposed improvements in fanning practises in Costa Rica and similar systems.
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6.
  • Sanderson Bellamy, Angelina, et al. (author)
  • What is in a label? Rainforest-Alliance certified banana production versus non-certified conventional banana production
  • 2016
  • In: Global Ecology and Conservation. - : Elsevier BV. - 2351-9894. ; 7, s. 39-48
  • Journal article (peer-reviewed)abstract
    • Export banana production in Latin America is pesticide intensive, receiving much negative publicity regarding human health problems and environmental degradation. The Rainforest Alliance (RA) certification scheme was established to certify farms that met a number of social, occupation health and environmental standards set by RA and their certifying body, the Sustainable Agriculture Network (SAN). This study was one of the first, independent studies of the environmental impact of some of the principles set by RA and SAN. The study focuses on insect and bird diversity as an indicator of ecosystem health. Five RA certified farms, six non-RA certified farms, and five organic certified farms were sampled. The data was analyzed with RDA multivariate analyses and Monte Carlo permutation tests. The results showed that RA certified farms had less insect diversity compared to non-RA certified farms and that both farm types had less insect diversity than organic farms. There was little difference between RA and non-RA certified farms with regards bird community composition. Thus, organic farming conserves biodiversity, while alternative environmental labels (e.g. a Rainforest alliance seal) may not have any visible positive effect on in-farm biodiversity. This study points to the need for improvements in SAN certification standards to achieve improved environmental conditions.
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7.
  • Miller, Frank, et al. (author)
  • Experiences with an adaptive design for a dose-finding study in patients with osteoarthritis
  • 2014
  • In: Contemporary Clinical Trials. - : Elsevier BV. - 1551-7144 .- 1559-2030. ; 37:2, s. 189-199
  • Journal article (peer-reviewed)abstract
    • Dose-finding studies in non-oncology areas are usually conducted in Phase II of the development process of a new potential medicine and it is key to choose a good design for such a study, as the results will decide if and how to proceed to Phase III. The present article has focus on the design of a dose-finding study for pain in osteoarthritis patients treated with the TRPV1 antagonist AZD1386. We describe different design alternatives in the planning of this study, the reasoning for choosing the adaptive design and experiences with conduct and interim analysis. Three alternatives were proposed: one single dose-finding study with parallel design, a programme with a smaller Phase Ila study followed by a Phase Ilb dose-finding study, and an adaptive dose-finding study. We describe these alternatives in detail and explain why the adaptive design was chosen for the study. We give insights in design aspects of the adaptive study, which need to be pre-planned, like interim decision criteria, statistical analysis method and setup of a Data Monitoring Committee. Based on the interim analysis it was recommended to stop the study for futility since AZD1386 showed no significant pain decrease based on the primary variable. We discuss results and experiences from the conduct of the study with the novel design approach. Huge cost savings have been done compared to if the option with one dose-finding design for Phase II had been chosen. However, we point out several challenges with this approach.
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8.
  • Bonaglia, Stefano, et al. (author)
  • Effect of reoxygenation and Marenzelleria spp. bioturbation on Baltic Sea sediment metabolism
  • 2013
  • In: Marine Ecology Progress Series. - : Inter Research. - 0171-8630 .- 1616-1599. ; 482, s. 43-55
  • Journal article (peer-reviewed)abstract
    • Nutrient reduction and the improvement of bottom water oxygen concentrations are thought to be key factors in the recovery of eutrophic aquatic ecosystems. The effects of reoxygenation and bioturbation of natural hypoxic sediments in the Baltic Sea were studied using a mesocosm experiment. Anoxic sediment box cores were collected from 100 m depth in Kanholmsfjärden (Stockholm Archipelago) and maintained in flow-through mesocosms with 3 treatments: (1) hypoxic: supplied with hypoxic water; (2) normoxic: supplied with oxic water; and (3) Marenzelleria: supplied with oxic water and the polychaete Marenzelleria spp. (2000 ind. m–2). After a 7 wk long conditioning period, net fluxes of dissolved O2, CH4, Fe2+, Mn2+, NH4+, NO2-, NO3-, PO43- and H4SiO4, and rates of nitrate ammonification (DNRA), denitrification and anammox were determined. Phosphate was taken up by the sediment in all treatments, and the uptake was highest in the normoxic treatment with Marenzelleria. Normoxic conditions stimulated the denitrification rate by a factor of 5. Denitrification efficiency was highest under normoxia (50%), intermediate in bioturbated sediments (16%), and very low in hypoxic sediments (4%). The shift from hypoxic to normoxic conditions resulted in a significantly higher retention of NH4+, H4SiO4 and Mn2+ in the sediment, but the bioturbation by Marenzelleria reversed this effect. Results from our study suggest that bioturbation by Marenzelleria stimulates the exchange of solutes between sediment and bottom water through irrigation and enhances bacterial sulfate reduction in the burrow walls. The latter may have a toxic effect on nitrifying bacteria, which, in turn, suppresses denitrification rates.
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  • Result 1-10 of 28
Type of publication
journal article (18)
other publication (5)
reports (4)
doctoral thesis (1)
Type of content
peer-reviewed (17)
other academic/artistic (6)
pop. science, debate, etc. (5)
Author/Editor
Svensson, Ola (16)
Gunnarsson, Jonas (7)
Svensson, Ola, 1971 (6)
Kvarnemo, Charlotta (6)
Tedengren, Michael (6)
Raymond, Caroline, 1 ... (6)
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Svensson, Ola, 1965- (6)
Cederwall, Hans (4)
van den Brink, Paul (3)
Raymond, Caroline (3)
Gunnarsson, Jonas S. (3)
van den Brink, Paul ... (3)
Sanderson Bellamy, A ... (3)
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Kvarnemo, Charlotta, ... (2)
Brüchert, Volker (2)
Rahm, Lars (2)
Shakeri Yekta, Sepeh ... (2)
Bonaglia, Stefano (2)
Lissåker, Maria (2)
Sköld, Mattias (1)
Singer, Anna (1)
Agrenius, Stefan (1)
Gustafsson, B (1)
Forsgren, Elisabet (1)
Magnhagen, Carin (1)
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Albertsson, Jan (1)
Andersson, Marica (1)
Swartz, Terese (1)
Manera, Jack L. (1)
Bertram, Michael G. (1)
Blom, Eva-Lotta (1)
Bartoli, M (1)
Mobley, Kenyon B. (1)
Reyier, Henrik (1)
Danielsson, Åsa (1)
Miller, Frank (1)
Björnsson, Marcus (1)
Karlsten, Rolf (1)
Lindström, Kai (1)
Hentati-Sundberg, J (1)
Manson, W. (1)
Lissaker, Maria (1)
Gunnarsson, Jonas, 1 ... (1)
Gunnar, Jonas (1)
Widbom, Bertil (1)
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University
University of Gothenburg (5)
University of Borås (5)
Linköping University (2)
Swedish Environmental Protection Agency (2)
Swedish University of Agricultural Sciences (2)
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Language
English (17)
Swedish (6)
Undefined language (5)
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Natural sciences (21)
Medical and Health Sciences (1)
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