No description available.

Because the mechanisms that lie behind the formation and preservation of asymmetric non-sorted stripes have not yet been established, and their particular shape has been given little attention by authors before, this study aims at giving a better understanding of the landforms and the environmental conditions under which they exist, with emphasis on under what circumstances the asymmetry develops. For this purpose, the roles of vegetation and snow were key concerns as well as the wind regime in relation to the vegetation, snow and morphology. The study consists of a thorough description of non-sorted stripes in the valley Gohpasvaggi, near Abisko field station in Northern Sweden. It comprises investigations of the ground thermal regime, soil moisture and other environmental parameters considered likely to have implications for the occurrence and appearance of the landforms. Results showed that the non-sorted stripe continues to the depth of ca 40-50 cm in the form of distortions of the deeper horizons, whereas the asymmetry is limited to the shallower A-horizon. In the stripe ridges there seems to be an upward movement in the soil that is likely physically driven (e.g. frost action). The furrow between the stripe ridges appears to be a quiescent area with normal soil development. The net downward movement here is likely biologically driven. The asymmetry can be related to the wind based on their corresponding direction and on the understanding of how feedback mechanisms involving wind, snow and vegetation works to maintain the micro topography. Differential frost heave and free convection of water in soil are plausible explanations for the origin of the non-sorted stripes in Gohpasvaggi. The current maintenance of the stripes is likely a combination of biological, physical and hydrological mechanisms that interact and depend on each other.

Current climate warming has a disproportionally large impact on Arctic glaciers and ice caps. In this thesis, I examined stratigraphic changes observed in the top ~15 m of two Arctic ice caps: one located at Svalbard (Lomonosovfonna) and the eastern Canadian Arctic Archipelago (Penny). The objective was to find out if and how the increasing regional temperatures have impacted the stratigraphy and densification rates of these ice caps, and particularly since the 1990s when Arctic warming accelerated. This was accomplished by analyzing and comparing recent (2000s) and earlier (1990s) ice-core density and stratigraphic measurements from these two ice caps, and also regional temperature data from Svalbard and the eastern Canadian Arctic over the period 1995-2013. Data over the amount and thickness of ice layers in the ice cores are also used and compared with the density development. A decrease in elevation for the formation of infiltration ice layers at Lomonsovfonna is concluded as well as a strong increase in temperature where the winter temperatures increase the most. In the ice cores it ́s also seen that each core has certain spatial variability when it comes to the distribution of infiltration ice.

No description available.

A changing climate could result in more intense rainfall events. This might result in an increasedload on stormwater systems in the urban environment. The building or updating of stormwatersystems is relatively expensive. To reduce costs, it is important to build the right type of system.This project aims to examine what type and size of stormwater system is most efficient from aneconomic perspective. Different parameters were analysed to compare alternative types of stormwater systems, includingthe effectiveness in retaining water, the building cost as well as the maintenance cost. In this reportthree alternative solutions were studied: retention tanks, retention ponds and a local solution inthe form of gravel swales. These alternative options were modelled using two different numericalmodels within the software MIKE URBAN. One smaller model over Viksjö and one larger modelover Kungsängen. Retention tanks and retention ponds were split into three systems with a differentnumber of facilities. The systems were examined for ten and one facility in both models, threefacilities in the smaller model and four in the larger. The local solution was modelled by mimickingthe swales spread across all catchment areas. To examine the effectiveness in retaining water all thesolutions and systems had to achieve a set of criteria: a max flow in the end pipe of the system,no flooding, and a rain with recurrence interval of 10 years and duration of 24 hours. From theset of critera a total retention volume was obtained from modelling the different systems in MIKEURBAN. The costs of building and maintaining the systems were calculated from the retentionvolumes. As the models had existing pipe-networks two results were obtained, one including andone excluding the cost of the changes made to the pipe network. The result calculated from modelling retention volumes in MIKE URBAN showed that the systemwith a larger number of facilities required a lower total retention volume than the systemswith fewer facilities. Retention tanks with ten facilities required the smallest total retention volumefollowed by retention ponds, whereas gravel swales required the largest volume. The local solutionrequired the least change of the pipe network followed by systems with ten, three/four and onefacility. The economic calculations showed that the building cost for retention ponds was the lowest followedby gravel swales and retention tanks. The maintenance cost of retention ponds was the highestfollowed by retention tanks and gravel swales. The total cost, pipes excluded, calculated from thederived retention volumes, building cost, and net present value of the maintenance for 40 years showedretention ponds being the best solution from an economic perspective. Retention ponds costaround four times less than retention tanks and gravel swales. Gravel swales and retention tankscost about the same. When the cost of the pipe network was included retention ponds were still the best option, followedby gravel swales and retention tanks. The difference in cost depending on the number of facilitiesincreased in favour of the systems with a larger amount of facilities when the cost of rebuildingparts the pipe network was included / En framtid med ett förändrat klimat kan innebära mer och kraftigare regn. Detta kan komma attställa högre krav på de dagvattensystem som existerar i dagens städer men även på de system somkommer byggas i framtiden. Att bygga nya och bygga om befintliga dagvattenanläggningar innebärkostnader. Syftet med detta projekt var att undersöka olika typer av dagvattenlösningar och hur storlekenpå dessa påverkar totalkostnaden för dagvattensystemet. Genom att undersöka detta var målet attbestämma vilken typ av anläggning, samt storleken på dessa, som är mest samhällsekonomisktlönsamma för nybyggnad och ombyggnad av dagvattensystem. För att bestämma vilken typ av dagvattenanläggning som är mest samhällsekonomiskt lönsam studeradeseffektivitet i att fördröja dagvatten, uppförandekostnad samt drift för olika typer av dagvattenlösningar.I denna rapport studerades dagvattendammar, fördröjningsmagasin och en lokallösning bestående av krossdiken. Krossdiken är ett metersdjupt dike fyllt med makadam. Hur effektivade olika lösningar var på att fördröja vatten utvärderades genom modellering i MIKE URBANdär två olika modeller användes, en mindre modell över Viksjö och en större modell överKungsängen. Modellerna som användes bestod av redan befintliga ledningsnät. Dagvattendammaroch fördröjningsmagasin fördelades på tre olika system. System ett bestod av mindre anläggningaroch fördelades på totalt tio anläggningar. System två med medelstora anläggningar bestod av tre anläggningari den mindre modellen och fyra anläggningar i den större. Det tredje systemet bestod avenbart en stor anläggning. Den lokala lösningen med krossdiken modellerade på ett sätt där krossdikenantogs vara utspridda över varje delavrinningsområde. Modelleringen av de olika systemenskedde genom att dessa utvärderades mot ett antal parametrar gemensamma för samtliga lösningar.Dessa parametrar innefattade flödesbegränsningar, typen av regn och översvämningar i modellen.Utifrån kraven som ställdes kunde den total fördröjningsvolymen som krävdes för de olika dagvattenlösningarnabestämmas. Utifrån de bestämda fördröjningsvolymer och kostnader för drift ochuppförande kunde en totalkostnad för de olika dagvattenlösningarna bestämmas. Två resultat presenterades,ett resultat inklusive kostnad för förändrade ledningar och ett resultat exklusive kostnadför ledningar. Resultatet från modelleringen visade att systemen med ett större antal anläggningar krävde lägrefördröjningsvolymer än systemen med färre anläggningar. Systemet med tio anläggningar med fördröjningsmagasinkrävde den minsta volymen följt av dagvattendammar. Krossdiken krävde denstörsta totala fördröjningsvolymen. Krossdiken krävde minst antal meter ombyggda ledningar följtav tio, tre/fyra och en anläggning. Resultatet från de ekonomiska undersökningarna visade att uppförandekostnaden för dammar varlägst följt av krossdiken och fördröjningsmagasin. Driftkostnaden var högst för dammar följt avfördröjningsmagasin och krossdiken. Slutkostnaden exklusive ledningar beräknades utifrån fördröjningsvolymernafrån modelleringen tillsammans med kostnader för uppförande och nuvärdetav driftkostnaden under 40 år. Slutkostnaden visade att dagvattendammar var den lösning som varmest samhällsekonomiskt lönsam, cirka fyra gånger billigare än övriga lösningar. Fördröjningsmagasinoch krossdiken var likvärdiga i totalkostnad exklusive ledningar. Då kostnaden inklusive förändrade ledningar beräknades var dammar billigast följt av krossdikenoch fördröjningsmagasin. Skillnaden mellan totalkostnad beroende på antalet anläggningar ökadetill fördel för de system med flera anläggningar då dessa krävde mindre ombyggnation av ledningar.

During the last 60 years the plastic production has increased more than 190 times and plasticpollution both at sea and land is a growing issue. Every year millions of tons of plastic waste fromland reaches the oceans, but the land-based sources are diffuse. One possible source of plasticwaste and microplastics are from plastic litter in urban areas which is common all over the world.The aim with this laboratory study was to study the photodegradation patterns of macroplasticsthat is usually found as litter in urban areas to contribute with knowledge and to theunderstanding of how macroplastics degrade to microplastics. The laboratory study wasstructured around the use of ultraviolet light exposure from UVA 340 nm lamps to acceleratephotodegradations of plastics in air. The test was divided into four different time intervals: stage7 days, stage 14 days, stage 28 days, and stage 56 days to study the evolution of plasticfragmentation over time. Effect of the UV radiation and test duration were combined to derivethe equivalent real time duration. Using Luleå as a benchmark the computed equivalence were0.27 years for every seven days of UV exposure. For stage 7d, a test with different mediums(water and air) were performed to compare the degradation processes between differentenvironments. However, for the longer time intervals air was the only tested environment. Newplastic products were bought which were among the most produced types of plastic or mostcommon plastic litter. The plastics were the following: polystyrene (PS) as plastic coffee cup lid,polypropylene (PP) as chocolate wrapping, polyethylene terephthalate (PET) as plastic bottle,low- density polyethylene (PE-LD) as plastic grocery bag and cellulose acetate (CA) as cigarettefilter or butts. The analytical techniques used were a particle size and number counter, with theselected particle size interval between 4-120 μm, and a camera mounted microscope to studyshapes of microplastic particles. Before photographing the particles, the samples were filtered ona 10 μm aluminium filter. The results showed that photodegradation with UV light did in factaccelerate the degradation process even for short time intervals. Potential for fragmentation ofparticles in air was larger, due to air being a more oxidizing environment and weakening theplastics. The results implied that the degradation processes for PS is slower in water compared tothe other plastics in the same environment. In PS there was a larger amount of particles for theUV- exposed samples compared to the other plastics. This is interpreted as it has a slowerdegradation processes due to the fact when looking on the other plastics in stage w.7 (in water),the control samples have a higher particle count than for the UV exposed samples. It can beinterpreted as PS does not become as effected by the UV light while in water compared to theother plastics. Therefore, the conclusion is that the particles degraded and became smaller thanthe analysed size range (4 μm) and were therefore not detected, consequently, showing a lowerparticle count. After 56 days of UV radiation the largest amount of detected particle mass wasproduced by PP (chocolate wrapping) with 0.0143 mg/cm2 material and the least amount ofdetected particle mass in stage 56d was of PE-LD (plastic bag) with 0.00042 mg/cm2 material.Based on the comparison of the water stage and air stages together with conclusions from earlierstudies, the potential for a substantial destructive breaking of large particle are considered higherin air than in water, because the oxidation weakens the material making it less resilient tomechanical stress.

Groundwater is a valuable source of drinking water and projects that manages groundwaterneed to prevent complications on the water’s characteristics. In an infrastructural project,groundwater reduced from elevated levels of nitrate needed to be recharged into the aquifer inthe area. This study aimed to describe important parameters to consider while performingartificial recharge. To fulfil the aim four research questions were answered; 1) What are thesurficial deposits in the area and how do they affect infiltration? 2) Are there any geologicalstructures that can influence the flow pattern due to infiltration? 3) What is the flow directionpattern in the area and how does it affect infiltration? 4) How does the infiltration attemptinfluence the groundwater levels and flow pattern in the aquifer? Previous literatures werestudied to find parameters that could affect the choice of location for an infiltration attempt.These parameters were used in Pugh’s concept selection and the most suitable location wasfound. To evaluate the attempt the groundwater levels were measured before and afterinfiltration to locate any local rise in groundwater levels. The results showed no rise ingroundwater levels that would change the flow pattern in the area and the location proved tobe suitable for infiltration in the future. The surficial deposits, groundwater flow direction andthe bedrock topology in the area proved to be important parameters that limited the possiblelocations for groundwater recharge. Future studies need to include these parameters and takeeconomic factors and land use into account to find appropriate infiltration locations.

Concentrations of potentially toxic metals in surface soils are important to investigate before building new residential areas. Prior to development of a residential area in Sundsvall, northern Sweden, it was observed that barium (Ba) concentrations in the soil at the site exceeded the guideline value of 200 mg kg-1 outlined by the Swedish Environmental Protection Agency. In this study, I aimed at determining the reason for the high Ba concentrations in the O horizon of soils from this latter area. 49 O horizon samples were collected from two separate transects (about 36 km long). A total of 43 Scots pine (Pinus sylvestris) needles were collected from both transects to determine potential Ba accumulation in plants. The O horizon and pine needle samples were analyzed using X-ray fluorescence spectrometer (XRF) to determine Ba concentrations. The total mean concentration of Ba was 426±289 mg kg-1 without any relationship to industrial sources. Barium concentrations were negatively correlated to soil organic matter (r = -0.885). Correlations between Ba, aluminum (Al), silicon (Si) and potassium (K) was r = 0.565, r = 0.486 and 0.525, a finding that suggests a strong positive coupling to elements typically found in silicate minerals. Barium concentrations in pine needle samples were below limit of detection (<LOD) suggesting that “plant pumping” via roots to the soil surface was an unlikely explanation for high concentrations in the O horizon. I conclude that the minerals in the O horizon originate from inmixing from the underlying mineral soil, therefore, high Ba concentrations in the study area is likely due to naturally occurring minerals.

Due to a lack of in-situ methods capable of detecting sub-lethal effects of pollutants on soil organisms, many polluted environments are not identified prior to pollution-induced changes in the soil fauna. Therefore, there is a need to develop new non-invasive methods to measure the health of soil organisms. This study aimed to assess to what extent surface borne vibrations can inform about ant health effects from exposure to sublethal doses of a pesticide (imidacloprid). Twelve ant colonies were set up with artificial nests and fed a glucose and imidacloprid solution (0.01 mg/L, 0.1 mg/L, 1 mg/L and 10 mg/L imidacloprid). After two days, five random ants were placed in an arena where the vibrations were recorded in five one-minute blocks using a Laser Doppler Vibrometer (LDV). No significant difference was found in activity per minute between the different concentrations, although there was a measurable increase in mortality between the concentrations from the second day of exposure to the fifth. Even so, the LDV may still be a viable method, as it clearly recorded vibrations caused by ant movement. If more ants were recorded for longer periods, and more replicates were used, it seems likely the method would have been sensitive enough to detect the effect of the studied pesticide. With an improved experiment design, using the LDV for this purpose may be possible, and the current lack of such a method necessitates further research on the subject.

I takt med urbanisering och förtätning av städer försvagas och minskar grönområden,ekosystem och den biologiska mångfalden. Samtidigt försämras ekosystemens förmågaatt leverera ekosystemtjänster som bidrar till att skydda människor från miljörisker samtfrämjar hälsa, livskvalitet och säkerhet. Det råder ofta ojämlikheter i tillgång avhögkvalitativa grönområden och exponering för miljörisker mellan socioekonomiskagrupper i samhället. Barn är mer känsliga än vuxna för exponering för miljörisker ochdrabbas oftast hårdast av dålig fysisk planering, särskilt i låginkomstkontexter. Det ärsåledes viktigt att ett barnperspektiv inkluderas i fysisk planering för att kunnasäkerställa alla barns rätt till nyttjande av grönområden av hög kvalitet ochekosystemtjänster. Syftet med studien är att undersöka och jämföra hur förskolor i olikasocioekonomiska områden nyttjar närliggande grönområden i sin verksamhet samtupplever och värderar ekosystemtjänster i dessa grönområden. Studieområden ärBredäng och Ålsten i Stockholm stad. För att besvara studiens syfte och frågeställningargranskades kartunderlag och intervjuer genomfördes med förskolepersonal frånförskolor i Bredäng respektive Ålsten. Studien visar på marginella skillnader mellanBredäng och Ålsten i hur förskolor nyttjar närliggande grönområden samt upplever ochvärderar ekosystemtjänster i dessa grönområden. Det förekommer däremot skillnader iavstånd till betydelsefulla grönområden som exempelvis skogsområden med förmåga attleverera många ekosystemtjänster. Förskolor prioriterar att besöka multifunktionellagrönområden av naturprägel för att tillgodogöra sig värdefulla ekosystemtjänsterfrämjande för barns välmående och utveckling.