| 1. |
- Eilola, Kari, et al.
(författare)
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SMHI reportsSMHI rep., Oceanogr : Swedish Meteorological and Hydrological Institute reports. OceanographySMHISMHI report. Oceanography 2007:37OceanographyROSMHI RO
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report is related to the BONUS project “Nutrient Cocktails in COAstal zones of the Baltic Sea” alias COCOA. The aim of BONUS COCOA is to investigate physical, biogeochemical and biological processes in a combined and coordinated fashion to improve the understanding of the interaction of these processes on the removal of nutrients along the land -sea interface. The report is especially related to BONUS COCOA WP 6 in which the main objective is extrapolation of results from the BONUS COCOA learning sites to coastal sites around the Baltic Sea in general. Specific objectives of this deliverable (D6.4) were to connect observed process rates with modelling data and ecosystem characteristics.In the report we made statistical analyses of observations from BONUS COCOA study sites together with results from the Swedish Coastal zone Model (SCM). Eight structural variables (water depth, temperature, salinity, bottom water concentrations of oxygen, ammonium, nitrate and phosphate, as well as nitrogen content in sediment) were found common to both the experimentally determined and the model data sets. The observed process rate evaluated in this report was denitrification. In addition regressions were tested between observed denitrification rates and several structural variables (lat itude, longitude, depth, light, temperature, salinity, grain class, porosity, loss of ignition, sediment organic carbon, total nitrogen content in the sediment, sediment carbon/nitrogen-ratio, sediment chlorphyll-a as well as bottom water concentrations of oxygen, ammonium, nitrate, and dissolved inorganic phosphorus and silicate) for pooled data from all learning sites.The statistical results showed that experimentally determined multivariate data set from the shallow, illuminated stations was mainly found to be similar to the multivariate data set produced by the SCM model. Generally, no strong correlations of simple relations between observed denitrification and available structural variables were found for data collected from all the learning sites. We found some non-significant correlation between denitrification rates and bottom water dissolved inorganic phosphorous and dissolved silica but the reason behind the correlations is not clear.We also developed and evaluated a theory to relate process rates to monitoring data and nutrient retention. The theoretical analysis included nutrient retention due to denitrification as well as burial of phosphorus and nitrogen. The theory of nutrient retention showed good correlations with model results. It was found that area-specific nitrogen and phosphorus retention capacity in a sub-basin depend much on mean water depth, water residence time, basin area and the mean nutrient concentrations in the active sediment layer and in the water column.
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| 2. |
- Gilbert, F., et al.
(författare)
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Sediment reworking by the burrowing polychaete Hediste diversicolor modulated by environmental and biological factors across the temperate North Atlantic. A tribute to Gaston Desrosiers
- 2021
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 541
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Tidskriftsartikel (refereegranskat)abstract
- Particle mixing and irrigation of the seabed by benthic fauna (bioturbation) have major impacts on ecosystem functions such as remineralization of organic matter and sediment-water exchange. As a tribute to Prof. Gaston Desrosiers by the Nereis Park association, eighteen laboratories carried out a collaborative experiment to acquire a global snapshot of particle reworking by the polychaete Hediste diversicolor at 16 sites surrounding the Northern Atlantic. Organisms and soft sediments were collected during May - July at different geographical locations and, using a common laboratory protocol, particulate fluorescent tracers (`luminophores') were used to quantify particle transport over a 10-day period. Particle mixing was quantified using the maximum penetration depth of tracers (MPD), particle diffusive coefficients (D-b), and non-local transport coefficients (r). Non-local coefficients (reflecting centimeter scale transport steps) ranged from 0.4 to 15 yr(-1), and were not correlated across sites with any measured biological (biomass, biovolume) or environmental parameters (temperature, grain size, organic matter). Maximum penetration depths (MPD) averaged similar to 10.7 cm (6.5-14.5 cm), and were similar to the global average bioturbation depth inferred from short-lived radiochemical tracers. MPD was also not correlated with measures of size (individual biomass), but increased with grain size and decreased with temperature. Bio-diffusion (D-b) correlated inversely with individual biomass (size) and directly with temperature over the environmental range (Q(10) similar to 1.7; 5-21 degrees C). The transport data were comparable in magnitude to rates reported for localized H. diversicolor populations of similar size, and confirmed some but not all correlations between sediment reworking and biological and environmental variables found in previous studies. The results imply that measures of particle reworking activities of a species from a single location can be generally extrapolated to different populations at similar conditions.
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| 3. |
- Lindqvist, Stina, 1981, et al.
(författare)
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Activities by Hediste diversicolor under different light regimes: Experimental quantification of particle reworking using time-resolved imaging
- 2013
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 448, s. 240-249
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Tidskriftsartikel (refereegranskat)abstract
- Particle reworking by the ragworm Hediste diversicolor was assessed by quantifying the transport of fluorescent particles (luminophores) added to the surface sediment during a 10 day experiment. Plexiglass cores and thin glass aquaria with fauna and controls were exposed to either 12 hour light/dark cycles or constant darkness. Luminophore distributions were evaluated by side-view imaging of the aquaria together with destructive sectioning and quantification of tracer distributions in both types of microcosms at the end of experiments. Tracer distributions were evaluated by the gallery-diffusor model, from which the biodiffusion (Db) and the non-local transport (r) coefficients were determined. In addition, the maximum penetration depth (MPD) of luminophores, the 2-D redistribution coefficient, and the transport rate were used as a suite of proxies to quantify particle reworking by fauna. All measured reworking proxies demonstrated a general decrease in transport of luminophores in darkness compared to light/dark cycles. The difference was significant for proxies determined from sectioning. Imaging of particle transport demonstrated that rates were ~ 30% higher during light/dark cycles, with ~ constant amount of particles transported on a daily basis. The effect of light was consistent in the two microcosm types. However, there was a significant difference in Db, while r and MPD were not significantly different between the cores and aquaria. Overall, these results suggest a light-triggered surface feeding by H. diversicolor. Our study highlights the importance of experimental settings for quantification of particle transport by fauna, and that light conditions and types of experimental microcosms need to be carefully considered during investigations of bioturbation in illuminated environments.
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| 4. |
- Lindqvist, Stina, 1981, et al.
(författare)
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Biogeochemistry in highly reduced mussel farm sediments during macrofaunal recolonization by Amphiura filiformis and Nephtys sp.
- 2009
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Ingår i: Marine environmental research. - : Elsevier BV. - 0141-1136. ; 67:3, s. 136-45
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Tidskriftsartikel (refereegranskat)abstract
- Mussel farming is considered a viable means for reducing coastal eutrophication. This study assessed the importance of bioturbation by recolonizing fauna for benthic solute fluxes and porewater distributions in manipulated mussel farm sediments. Three consecutive time-series flux incubations were performed during an experimental period of three weeks in sieved farm sediment treated with the brittle star Amphiura filiformis and the polychaete Nephtys sp. The functional behavior of Nephtys sp. and interactions between Nephtys sp. and the spontaneously colonizing spionid Malacoceros fuliginosus determined the biogeochemical response in the Nephtys sp. treatment. For example, the oxic zone was restricted and benthic nitrate and silicate fluxes were reduced compared to the brittle star treatment. A. filiformis seemed to enhance the bioadvective solute transport, although an increased supply of oxygen was due to the highly reducing conditions of the sediment mainly seen as secondary effects related to porewater distributions and benthic nutrient fluxes.
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| 5. |
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| 6. |
- Lindqvist, Stina, 1981
(författare)
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Transport by Benthic Macrofauna: Functional Classification and Biogeochemical Response
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Burrowing and reworking activities by benthic macrofauna regulate rates and pathways during organic matter mineralisation in bioturbated sediments. In so doing, they also affect the overall cycling of elements crucial in the biosphere (e.g. C, N, P, Fe, Mn and S). Feeding, burrowing, respiratory ventilation and construction activities by benthic fauna alter sediment structures, creating a mosaic of microenvironments within the sedimentary deposit. Fauna regulate input of organic material to the sediment and the vertical distribution of solids and solutes within the sediment, thereby influencing sediment-water exchange of gases and solutes such as carbon dioxide, oxygen and nutrients. While the existence of a relationship between faunal activity and biogeochemical responses is clearly established, the mechanisms behind this influence are not well constrained. In order to understand sediment response to changes, natural or anthropogenic, the role of benthic macrofauna for physical, chemical and biological processes need to be clarified. Because of the different behaviour of faunal species in sediments, observed effects of benthic macrofauna on biogeochemical variables are not necessarily directly and straight-forwardly coupled to the biomass of fauna. In fact, biomass has proven to be a relatively poor proxy for bioturbation throughout experiments presented in this thesis. Moreover, the relation may be non-linear and vary significantly between species and functional behaviour of fauna. This thesis is based on results from several experiments designed to quantify the impact of bioturbation by individual species for element cycling in surface sediments, with focus on the small-scale transport mechanisms in bioturbated sediments. The functional behaviour of fauna and feedbacks between macrofauna reworking activities and chemical signals in sulphidic environments was studied by introducing two species (the brittle star Amphiura filiformis and the polychaete Nephtys incisa) to severely reducing sediments from beneath a mussel farm. The biogeochemical response to the different modes of reworking was significantly different between the two species. Amphiura filiformis generally enhanced bioadvective solute transport, while Nephtys sp. restricted the oxic zone and reduced benthic fluxes of nitrate and silicate. Fauna in shallow sediments experience a daily light- and dark cycle. The diurnal light regime was experimentally demonstrated to significantly affect reworking activities by the polychaete Hediste diversicolor. An increased activity was observed for specimens of H. diversicolor that were exposed to a natural light cycle in comparison to those in constant darkness, probably related to a decrease in surface feeding. A light-dependent diurnal reworking behaviour has ramifications for the daily transformation of elements in shallow illuminated sediment systems. An important result from this thesis is that activities by macrofauna in sediments and their significance for different biogeochemical processes, are too complex to be explained by only one or two bioturbation proxies. Assessments by multivariate analysis indicated that a general and repeatable comparison and classification associated with modes of bioturbation can be readily achieved by evaluating multiple experimental proxies for bioturbation. Similar functional groups were found by multivariate analysis on particle reworking by imaging or multiple transport processes in cores, i.e. independent of evaluation techniques for transport.
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| 7. |
- Nyström, Michelle, et al.
(författare)
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Making the right decision for our children's future: Parents' perceptions of active school travel in disadvantaged neighborhoods
- 2023
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Ingår i: Journal of Transport & Health. - : Elsevier. - 2214-1405 .- 2214-1413. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundChildren's possibility to be physically active is linked to their parent's socioeconomic status. The use of active travel has the potential to increase daily physical activity among children. Parents are the gate-keepers to children using active school travel (AST) and their perceptions has shown to impact children's travel mode. Few studies have explored parents' perceptions about AST in disadvantaged neighborhoods and there is a lack of knowledge of their perceptions of the physical and social environment associated with school travel.PurposeTo explore parents’ perceptions towards AST when living in disadvantaged neighborhoods.MethodsTwelve parents participated in semi-structured interviews, and a qualitative content analysis was used to analyze the data.ResultsThe findings show that parents faced dilemmas, striving to facilitate AST. Parents perceptions are presented as A, B, C categories that are likely to be important when promoting AST in disadvantaged neighborhoods, Acknowledging AST advantages, Balancing barriers, and Creating opportunities to use AST.ConclusionsDespite having a positive attitude towards AST, insecure neighborhoods and social exclusion affect parents'descisions about AST. When promoting AST in disadvantaged neighborhoods, measures to enable AST should include efforts supporting community building, social participation, road safety and ways of promoting bicycling. Engaging children in AST could have a positive influence on their independent mobility, thereby impacting their development and preparing them for the future.
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| 8. |
- Rutberg, Stina, et al.
(författare)
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My Way to School Through a Camera Lens: Involving Children to Inform a Policy Recommendation on Active School Travel
- 2024
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Ingår i: Health Promotion Practice. - : Sage Publications. - 1524-8399 .- 1552-6372.
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Tidskriftsartikel (refereegranskat)abstract
- Active school travel (AST) is an effective approach for increasing children’s physical activity and independent mobility, but policy supporting AST is lacking. This study aims to explore children’s experiences of AST to inform a policy recommendation. Photovoice methodology with a qualitative approach was applied, with children taking pictures on their way to school. This was followed by focus groups where the children explored their experiences of AST based on their photos. The data were analyzed using qualitative content analysis. The results show that the children valued independent mobility and wanted to be involved in decisions about their travels; they also expressed feelings of increased responsibility and personal growth as a consequence. Although the children recognized areas of improvement regarding infrastructure, especially regarding heavy traffic that jeopardized travel safety, they continued using AST. Finally, the children talked about the value of the health and environmental benefits of AST. Opportunities for friendship, play, and making decisions about their own time were highlighted as important incentives. The benefits from AST are many for children, as well as for society. The result has informed policy recommendations for AST, and the children’s input will be used to communicate the recommendations. Listening to the voices of children could be a steppingstone toward forming future healthy mobility initiatives. In that process, it is key to include children’s perspectives when formulating the AST policy for successful adoption and implementation.
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| 9. |
- Rutberg, Stina, et al.
(författare)
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Prövning och analys av barnets bästa när det gäller nationella rekommendationer för aktiva skolresor : en barnkonsekvensanalys
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I Sverige saknas en nationell rekommendation gällande aktiva skolresor. Samtidigt vet vi att barn och unga i Sverige rör på sig för lite. Aktiva resor till och från skolan är ett effektivt sätt att öka den fysiska aktiviteten och det är ett prioriterat område i WHO global action plan om fysisk aktivitet. Det aktiva resandet i dagens transportsystem har större positiva hälsoeffekter än de negativa effekterna av buller, luftkvalitet och trafiksäkerhet tillsammans. Det bidrar positivt till uppfyllelsen av flera mål i Agenda2030. Att barn själva så långt det är möjligt utifrån ålder, mognad och funktionsförmåga får ta ansvari sitt resande är en förutsättning för identitetsskapande och välbefinnande. Tyvärr förväntas de aktiva resorna minska ytterligare om inte riktade åtgärder sätts in.Barns aktiva resor är beroende av trafikmiljön och varierar mellan platser och situationer vilket gördet svårt att basera en rekommendation på ålder. Att det förekommer uttryck såsom ”att barn inteär mogna att cykla i trafikmiljöer förrän vid 12-års ålder” i olika policydokument ökar behovet av nyarekommendationer för att guida vårdnadshavare, skolor, samhällsplanerare och väghållare.I denna barnkonsekvensanalys prövas rekommendationen mot barns behov. En prövning och analys av barnets bästa är ett underlag för att synliggöra och stärka barnrättsperspektivet i beslut som fattas i frågor som rör barn direkt eller indirekt. För att säkerställa att barnets bästa tillgodoses ska en prövning göras inför varje beslut som berör barn. FN:s barnrättskommitté nämner bl.a. utarbetande av policyer och rekommendationer som exempel på sammanhang där en barnkonsekvensanalys ska göras. En barnkonsekvensanalys är ett verktyg för att omsätta barnrättslagen i handling och synliggöra barnets bästa.
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