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  • 1.
    Backman, Fredrick
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Från föhn till feu!: Esrange och den norrländska rymdverksamhetens tillkomsthistoria från sekelskiftet 1900 till 19662010Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This essay is about the origin, planning and establishment of the European Space Research Organisation's (ESRO) sounding rocket base Esrange outside Kiruna in Northern Sweden. Three main questions are examined. First I show there were not just scientific and technical but also political, economical as well as military reasons to build a European rocket base. Second, I scrutinize the reasons to choose Northern Sweden as the location for the rocket base. As it turns out, the main reasons were the favourable location of Northern Sweden within the aurora oval zone, the proximity of the Kiruna Geophysical Observatory, and the possibility to use a large, although not quite uninhabited, area where the launched rockets could crash. Finally, I examine the difficulty of talking about boundaries of various kinds, such as temporal, spatial and functional. The essay also provides a discussion on possible ways to continue research on this topic.

  • 2.
    Becher, Marina
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Cryogenic soil processes in a changing climate2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A considerable part of the global pool of terrestrial carbon is stored in high latitude soils. In these soils, repeated cycles of freezing and thawing creates soil motion (cryoturbation) that in combination with other cryogenic disturbance processes may play a profound role in controlling the carbon balance of the arctic soil. Conditions for cryogenic soil processes are predicted to dramatically change in response to the ongoing climate warming, but little is known how these changes may affect the ability of arctic soils to accumulate carbon. In this thesis, I utilize a patterned ground system, referred to as non-sorted circles, as experimental units and quantify how cryogenic soil processes affect plant communities and carbon fluxes in arctic soils. I show that the cryoturbation has been an important mechanism for transporting carbon downwards in the studied soil over the last millennia. Interestingly, burial of organic material by cryoturbation appears to have mainly occurred during bioclimatic events occurring around A.D. 900-1250 and A.D. 1650-1950 as indicated by inferred 14C ages. Using a novel photogrammetric approach, I estimate that about 0.2-0.8 % of the carbon pool is annually subjected to a net downward transport induced by the physical motion of soil. Even though this flux seems small, it suggests that cryoturbation is an important transporter of carbon over centennial and millennial timescales and contributes to translocate organic matter to deeper soil layers where respiration proceeds at slow rates. Cryogenic processes not only affect the trajectories of the soil carbon, but also generate plant community changes in both species composition and abundance, as indicated by a conducted plant survey on non-sorted circles subjected to variable differential frost heave during the winter. Here, disturbance-tolerant plant species, such as Carex capillaris and Tofieldia pusilla, seem to be favoured by disturbance generated by the differential heave. Comparison with findings from a previous plant survey on the site conducted in the 1980s suggest that the warmer temperatures during the last decades have resulted in decreased differential heave in the studied non-sorted circles. I argue that this change in cryogenic activity has increased abundance of plants present in the 1980s. The fact that the activity and function of the non-sorted circles in Abisko are undergoing changes is further supported by their contemporary carbon dioxide (CO2) fluxes. Here, my measurements of CO2 fluxes suggest that all studied non-sorted circles act as net CO2 sources and thus that the carbon balance of the soils are in a transition state. My results highlight the complex but important relationship between cryogenic soil processes and the carbon balance of arctic soils.

  • 3.
    Becher, Marina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Börlin, Niclas
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Measuring soil motion with terrestrial close range photogrammetry in periglacial environments2014Conference paper (Other academic)
    Abstract [en]

    Cryoturbation plays an important role in the carbon cycle as it redistributes carbon deeper down in the soil where the cold temperature prevents microbial decomposition. This contribution is also included in recent models describing the long-term build up of carbon stocks in artic soils. Soil motion rate in cryoturbated soils is sparsely studied. This is because the internal factors maintaining cryoturbation will be affected by any excavation, making it impossible to remove soil samples or install pegs without changing the structure of the soil. So far, mainly the motion of soil surface markers on patterned ground has been used to infer lateral soil motion rates. However, such methods constrain the investigated area to a predetermined distribution of surface markers that may result in a loss of information regarding soil motion in other parts of the patterned ground surface.

    We present a novel method based on terrestrial close range (<5m) photogrammetry to calculate lateral and vertical soil motion across entire small-scale periglacial features, such as non-sorted circles (frost boils). Images were acquired by a 5-camera calibrated rig from at least 8 directions around a non-sorted circle. During acquisition, the rig was carried by one person in a backpack-like portable camera support system. Natural feature points were detected by SIFT and matched between images using the known epipolar geometry of the calibrated rig. The 3D coordinates of points matched between at least 3 images were calculated to create a point cloud of the surface of interest. The procedure was repeated during two consecutive years to be able to measure any net displacement of soil and calculate rates of soil motion. The technique was also applied to a peat palsa where multiple exposures where acquired of selected areas.

    The method has the potential to quantify areas of disturbance and estimate lateral and vertical soil motion in non-sorted circles. Furthermore, it should be possible to quantify peat erosion and rates of desiccation crack formations in peat palsas. This tool could provide new information about cryoturbation rates that could improve existing soil carbon models and increase our understanding about how soil carbon stocks will respond to climate change.

  • 4.
    Becher, Marina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Olofsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Berglund, Louise
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Decreased cryogenic disturbance: one of the potential mechanisms behind the shrubification of non-sorted circles in subarctic SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    During the last few decades, the arctic has experienced large-scale vegetation changes often evident as widespread greening (increased NDVI) in satellite images. Understanding the mechanisms behind this greening is crucial for our ability to predict future vegetation changes. The objective of this study was to test the hypothesis that decreased cryogenic disturbances have contributed to the greening of patterned ground fields (non-sorted circles) in the study site (Abisko, Northern Sweden) during the last few decades. The hypothesis was tested by surveying the composition of plant communities across a gradient in cryogenic disturbance and by reinvestigating plant communities previously surveyed in the 1980s to scrutinise how these communities changed in response to reduced cryogenic disturbance. Whereas the historical changes in species occurrence associated with decreased cryogenic disturbances were fairly consistent with the changes along the contemporary gradient of cryogenic disturbances, the species abundance revealed important transient changes highly dependent on the initial plant community composition. Our results imply that the decreased environmental stress from differential heave during winter in recent decades is one of the mechanisms that has contributed to the greening of the patterned ground in the study area, although more than a few decades are likely required before this decreased stress contributes in a substantial way to the on-going shrubification. 

  • 5.
    Bigler, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gälman, Veronika
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Numerical simulations suggest that counting sums and taxonomic resolution of diatom analyses to determine IPS pollution and ACID acidity indices can be reduced2010In: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 22, no 5, 541-548 p.Article in journal (Refereed)
    Abstract [en]

    Implementation of the European Union Water Framework Directive and associated national guidelines has emphasized the value of using biota, such as epilithic diatoms in streams, as indicators of water quality. However, guidelines for evaluating diatom samples have been established without explicitly evaluating their statistical robustness. We used epilithic diatom samples from 73 streams in northern Sweden and simulated the effects of variations in the counting sum size and taxonomic resolution of classifications for two indices indicating pollution (Indice de Polluo-sensibilité Spécifique, IPS) and acidity (acidity index for diatoms, ACID). Instead of the stipulated 400, we found that a count sum of 40 diatom valves for 50 streams, and 80 valves for 60 streams, would have been sufficient to obtain the same IPS index classification. The ACID index is more sensitive to count sum reductions, since the same classification would only have been obtained for 12 streams with 40 counted diatom valves or 24 streams with a count of 80 valves. Excluding rare taxa had negligible effects on the IPS and ACID indices. Excluding taxa occurring with less than 1.0% frequency affected the IPS classification of only one stream, and excluding taxa with less than 2.5% and 5.0% frequencies affected those of just one and no streams, respectively. The ACID index was affected for none, five, and 12 streams, respectively. At least in relatively unpolluted regions such as northern Sweden, our simulations suggest that a simplified methodological approach with site-specific counting sum sizes and reduced taxonomical resolution could be adopted, taking into account the way sites are classified in relation to established class boundaries. The simplified method is a step forward in improving the cost efficiency for stream monitoring, as costs of diatom analysis to obtain identical IPS and ACID classifications of our streams could be reduced considerably. Before the simplified method can be widely adopted, further simulations including regions with a higher proportion of polluted streams are required.

  • 6.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Yu, Ruilian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. College of Chemical Engineering, Huaqiao University, Xiamen, Fujian 361021, P.R. China.
    Hansson, Sophia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Classen, Neele
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Karlsson, Jon
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Mining, Metallurgy and the Historical Origin of Mercury Pollution in Lakes and Watercourses in Central Sweden2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 15, 7984-7991 p.Article in journal (Refereed)
    Abstract [en]

    In Central Sweden an estimated 80% of the lakes contain fish exceeding health guidelines for mercury. This area overlaps extensively with the Bergslagen ore region, where intensive mining of iron ores and massive sulfide ores occurred over the past millennium. Although only a few mines still operate today, thousands of mineral occurrences and mining sites are documented in the region. Here, we present data on long-term mercury pollution in 16 sediment records from 15 lakes, which indicate that direct release of mercury to lakes and watercourses was already significant prior to industrialization (<AD 1800). Thirteen of our lakes show increases in mercury from 3-fold-equivalent to the enrichment factor in many remote lakes today-to as much as 60-fold already during the period AD 1500-1800, with the highest values in the three lakes most closely connected to major mines. Although the timing and magnitude of the historical increases in mercury are heterogeneous among lakes, the data provide unambiguous evidence for an incidental release of mercury along with other mining metals to lakes and watercourses, which suggests that the present-day problem of elevated mercury concentrations in the Bergslagen region can trace its roots back to historical mining.

  • 7.
    Buckland, Paul C.
    et al.
    University of Sheffield, UK.
    Panagiotakopulu, Eva
    Edinburgh University, Scotland.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies, Environmental Archaeology Lab.
    Perdikaris, Sophia
    Skidmore, Peter
    Insect faunas from Medieval Langenes in Arctic Norway2006In: Proceedings from the VIII Nordic Conference on the Application of Scientific Methods In Archaeology, Umeå, Sweden, 2001. / [ed] Engelmark, Roger & Linderholm, Johan, 2006, 17-32 p.Conference paper (Refereed)
    Abstract [en]

    Cultural sediments containing significant amounts of fish bone at Langenesværet, Vesterålen, Northern Norway provide an opportunity to characterise activity during and prior to the establishment of a late medieval commercial fishing station (fiskevaer). Radiometric and AMS dating techniques are used to establish a chronology for the deposits, while activities associated with the sediments are characterised fossil insect faunas. The results highlight a series of problems with the dating of the heavily disturbed organic deposits of many archaeological sites, and the need for greater care in sample selection and interpretation.

  • 8.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab. Umeå University, Faculty of Arts, Humlab.
    The Bugs Coleopteran Ecology Package (BugsCEP) database: 1000 sites and half a million fossils later2014In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 341, 272-282 p.Article in journal (Refereed)
    Abstract [en]

    The Bugs database project started in the late 1980s as what would now be considered a relatively simple system, albeit advanced for its time, linking fossil beetle species lists to modern habitat and distribution information. Since then, Bugs has grown into a complex database of fossils records, habitat and distribution data, dating and climate reference data wrapped into an advanced software analysis package. At the time of writing, the database contains raw data and metadata for 1124 sites, and Russell Coope directly contributed to the analysis of over 154 (14%) of them, some 98790 identifications published in 231 publications. Such quantifications are infeasible without databases, and the analytical power of combining a database of modern and fossil insects with analysis tools is potentially immense for numerous areas of science ranging from conservation to Quaternary geology.

    BugsCEP, The Bugs Coleopteran Ecology Package, is the latest incarnation of the Bugs database project. Released in 2007, the database is continually added too and is available for free download from http://www.bugscep.com. The software tools include quantitative habitat reconstruction and visualisation, correlation matrices, MCR climate reconstruction, searching by habitat and retrieving, among other things, a list of taxa known from the selected habitat types. It also provides a system for entering, storing and managing palaeoentomological data as well as a number of expert system like reporting facilities.

    Work is underway to create an online version of BugsCEP, implemented through the Strategic Environmental Archaeology Database (SEAD) project (http://www.sead.se). The aim is to provide more direct access to the latest data, a community orientated updating system, and integration with other proxy data. Eventually, the tools available in the offline BugsCEP will be duplicated and Bugs will be entirely in the web.

    This paper summarises aspects of the current scope, capabilities and applications of the BugsCEP database and software, with special reference to and quantifications of the contributions of Russell Coope to the field of palaeoentomology as represented in the database. The paper also serves to illustrate the potential for the use of BugsCEP in biographical studies, and discusses some of the issues relating to the use of large scale sources of quantitative data.

    All datasets used in this article are available through the current version of BugsCEP available at http://www.bugscep.com.

  • 9.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Eriksson, Erik J.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Palm, Fredrik
    Umeå University, Faculty of Arts, Humlab.
    SEAD - The Strategic Environmental Archaeology Database: Progress Report Spring 20142014Report (Other academic)
    Abstract [en]

    This report provides an overview of the progress and results of the VR:KFI infrastructure projects 2007-7494 and (825-)2010-5976. It should be considered as a status report in an on-going long-term research infrastructure development project.

  • 10.
    Classen, Neele
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    1000 years of environmental changes in Falun, Sweden: Lake Sediment as source material2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this study was to get a better knowledge of the metal pollution and the mining

    history of the Falun area. It adds new information on the geochemistry of the lakes and the

    beginning of mining in the Falun region, together with the influence of early land use. The

    main focus is on three lakes Hagtjärnen, Stugutjärnen and Nästjärnen, which were previously

    dated and analyzed regarding acidification by Anna Ek. Additional supporting information is

    provided from records from 10 other lakes, which are located at distances between 0-27 km

    from the Falun Copper mine. Another specific focus is on the lake Tisken, which has been

    assumed over the past 50 years to represent faithful historical record of mining in the Falun

    area. In this study this lake record was dated and analyzed, too. The analyses of all the lakes

    included resulted in four significant phases of environmental change, indicating the start of

    agriculture and mining, the development of each sector, as well as the sharp increase in

    pollution in the modern time period. Phase I covers the time period A.D. 700-1000 and

    represents the time of the early beginning of land use and small scale mining activities. Phase

    II represents the time between A.D. 1200 to 1450, which is dominated by an ongoing

    development of mining and a sharp increase in metal concentrations and occurrence of

    cultivated plants and plants favored by disturbance from A.D. 1450 onwards. The third phase,

    representing the year A.D. 1540, clearly displays another period of sharp increases among the

    metal concentrations, which coincides with a peak in Cu production volumes. Phase IV

    covers the time period A.D. 1750-1900, referred to as Modern time, and features a clear

    increase in Pb pollution, which is linked to the introduction of tetra ethyl Pb in the 1970s.

    Other metals increase also, together with cultivated plants like cereals, indicating an ongoing

    expansion of mining and agriculture. The results also indicate that Cu was not emitted as far

    as other elements, like for example Pb, which led to great pollution only in the lakes close to

    the Falun mine.

    Another important finding is that the lake Tisken does not represent a continual historical

    record, because the sediment is not a chronological sequence and instead likely represents

    mostly a catastrophic input of debris of mixed age. The C-14 dating shows, that the sediment

    is mixed and disturbed in Tisken. As a consequence, the long-standing interpretation of

    Tisken’s sediment record as an archive for the historical start and late development of mining

    at the Falun copper mine is incorrect

  • 11.
    Eckerberg, Katarina
    et al.
    Umeå University, Faculty of Social Sciences, Department of Political Science.
    Nilsson, Måns
    Gerger-Swartling, Åsa
    Söderberg, Charlotta
    Umeå University, Faculty of Social Sciences, Department of Political Science.
    Institutional analysis of energy and agriculture2007In: Environmental policy integration in practice: shaping institutions for learning / [ed] Måns Nilsson och Katarina Eckerberg, London: Earthscan , 2007, 111-136 p.Chapter in book (Refereed)
  • 12.
    Edin, Malin
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Miljöpåverkan av äggproduktion: En jämförelse mellan Lilluns ägg och andra svenska äggproducenter2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report was to compare Lilluns egg production with other Swedish egg producers based on the flow of nutrients (nitrogen, phosphorus and potassium) in the egg production systems. The main focus in the report was the utilization rate of the forage and the excess of nutrients per kg egg. Additionally, the purpose was to identify the environmental impact from Lilluns egg production and compare the results with other egg producers. The inflow of nutrients associated with forage and poultry was compared with the nutrients that were exported from the production. All of the egg producers in this study had an excess of nutrients. The utilization rate of the forage for Lilluns egg was 47 %, the other egg producers in this study had an utilization rate between 45-50 %. The results showed that Lilluns egg had an excess of nitrogen of 0,04 kg/kg eggs. Lilluns egg also had an excess of phosphorus and potassium. The excess of phosphorus was 0,01 kg/kg eggs and 0,013 kg/kg eggs for potassium. The results showed that all the egg producers in this study had an excess of all the nutrients. The conclusion is that the egg production systems in this study have a similar utilization rate and the excess of nutrients per kg egg was also similar for all the egg producers.

  • 13.
    Eklund, John
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Anläggning och Restaurering av fågelvåtmarker: Lokalisering av våtmarksobjekt i odlingslandskap som är lämpliga för restaurering och anläggning2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There is a shortage of wetlands in the farming landscape and as a direct consequence farmland birds are decreasing in number. The need of restoring and constructing wetlands is therefore great. The purpose of this study was to locate potential objects in the farming landscape that is suitable for creating and restore wetland bird habitats within Västernorrland and Västerbotten County. A method was developed that stepwise pinpoint potential object in the agricultural landscape where seven selection parameters that define a suitable objects criterion where used. To evaluate the located objects a small number was observed in the field and furthermore a simulation of surface water was conducted to evaluate the landscape criteria’s and to calculate the land use. 98 objects were located, 59 restoration and 39 construction objects. The water surface simulation was conducted on four objects where one of the objects did not show favorable condition, this expresses the importance testing the objects early on. A large number of objects was located but the study indicates that there is possibly far more that object that wasn’t located that has good potential. The method has potential to develop higher accuracy and a ranking system. For the future this study suggests a 6 step work process to fully execute a wetland project, where this method constitutes the first step. 

  • 14. Gilichinsky, Michael
    et al.
    Sandström, Per
    Reese, Heather
    Kivinen, Sonja
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Moen, Jon
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Nilsson, Mats
    Mapping ground lichens using forest inventory and optical satellite data2011In: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 32, no 2, 455-472 p.Article in journal (Refereed)
    Abstract [en]

    Lichen is a major forage resource for reindeer and may constitute up to 80% of areindeer’s winter diet. The reindeer grazing area in Sweden covers almost half of thecountry, with reindeer using mountainous areas in the summer and forested areas inthe winter. Knowledge about the spatial distribution of ground lichens is importantfor both practical and decision-making purposes. Since the early 1980s, remotesensing research of lichen cover in northern environments has focused on reindeergrazing issues. The objective of this study was to use lichen information collected inthe Swedish National Forest Inventory (NFI) as training data to classify opticalsatellite images into ground lichen cover classes. The study site was located within thereindeer husbandry area in northern Sweden and consisted of the common areabetween two contiguous Satellite Pour l’Observation de la Terre (SPOT)-5 scenesand one Landsat-7 Enhanced Thematic Mapper Plus (ETMþ) scene. Three classificationmethods were tested: Mahalanobis distance, maximum likelihood andspectral mixture analysis. Post-classification calibration was applied using a membershipprobability threshold in order to match the NFI-measured proportions oflichen coverage classes. The classification results were assessed using an independentlycollected field dataset (229 validation areas). The results demonstrated highclassification accuracy of SPOT imagery for the classification of lichen-abundantand lichen-poor areas when using theMahalanobis distance classifier (overall accuracy84.3%, kappa ¼ 0.68). The highest classification accuracy for Landsat wasachieved using a maximum likelihood classification (overall accuracy 76.8%, kappa¼ 0.53). These results provided an initial indication of the utility of NFI data astraining data in the process of mapping lichen classes over large areas.

  • 15.
    Gustavsson, Leif
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Mahapatra, Krushna
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Implementering av energieffektiviseringsåtgärder i befintlig bebyggelse: Report prepared for the Swedish Energy Agency2010Report (Other (popular science, discussion, etc.))
    Abstract [en]

    There is great potential to improve energy efficiency in existing Swedish residential buildings. However, the successful implementation of efficiency measures depends on economical and technical factors, as well as on the attitudes and perceptions of the relevant actors. A better understanding of their attitudes and perceptions may influence the design of suitable policy measures that increase the adoption of energy efficiency measures. In this context, we conducted mail-in surveys completed by owners of detached houses, chairmen of co-operative housing associations (bostadsrättsförening) and municipality energy advisers in Sweden. We also interviewed window sellers/installers in Jämtland.

    Results show that it was important for the majority of homeowners to reduce their household energy use, with most undertaking no-cost measures (e.g., switching off lights). However, 70–90% of the responding homeowners had no intention of adopting building envelope measures over the next 10 years. The main reason for non-adoption was that homeowners were satisfied with the physical condition and thermal performance of their existing building envelope components. Homeowners who thought their energy cost was high were more likely to adopt an investment measure compared to those who thought their energy cost was low. Investment costs and annual energy cost savings were the most important factors in adoption of energy efficient building envelope measures. Therefore, economic incentives may induce homeowners to adopt energy efficiency investment measures. However, a large percentage (64%) of homeowners was unaware of the existence of government support for reducing household energy use. Information campaigns announcing the availability of economic incentives and the cost advantages of energy efficiency measures may be helpful in the adoption decision.

    Homeowners‘ considered interpersonal sources, builders, installers and energy advisers as important sources of information for their adoption of energy efficiency measures. Though a large percentage of respondents considered energy advisers as an important source of information, only 14% of homeowners had contacted an energy adviser in the past. Our findings suggest that the energy advice service is important for homeowners, but more efforts are needed to increase homeowners‘ awareness of and satisfaction with such services. The majority of municipal energy advisers were of the opinion that more training in technical aspects of energy issues and increased financial support could improve their performance.

    Installers and material suppliers are important actors in homeowners‘ adoption of energy efficiency measures. For example, approximately 53% of responding homeowners to a survey in Jämtland/Västernorrland stated that the window seller/installer from whom they had bought windows had recommended a particular type of window, and 97% had installed the windows that were recommended. The window sellers/installers in Jämtland prefer a window that is ―reasonably‖ energy efficient. They believe that windows with a U-value of 1.2 W/m2K are good and there is no reason to further improve the energy efficiency. The majority did not recommend windows with U-value <1.2 W/m2K. They were concerned about the condensation issues and high prices of such windows. This may influence the diffusion of very energy efficient windows in Swedish detached houses.

    About 80-95% of chairmen in co-operative housing associations who responded to our survey had no intention of adopting building envelope measures over the next 10 years. They were satisfied with the existing building envelope components, which may be one of the reasons for this lack of intention. As in the case of owners of detached houses, economic factors, like annual energy cost savings and investment costs, guide the implementation of energy efficiency investment measures in co-operative housing associations. However, about 66% of the responding chairmen did not consider financial constraint as a barrier to implementing investment intensive energy efficiency measures. For 54% of the respondents limited in-house competency to evaluate the benefits of energy efficiency measures was the main barrier.

    The majority of owners of detached houses (80%) and chairmen of co-operative housing associations (70%) perceived that economic policy instruments, such as investment subsidies and tax deductions, would encourage them to implement energy efficiency measures. Other policy instruments, especially information instruments, were perceived as less effective. Among various information policies, increasing the frequency of meter reading received the highest approval with 38% of homeowners, whereas approximately 41% of housing association chairmen thought that individual metering of heating and hot water use could be effective. Approximately 30% of homeowners and housing association chairmen thought that energy declaration was effective.

  • 16.
    Gydemo Östbom, Viktor
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sedimentation in a small lake, more complex than previously assumed.: Bathymetrical and geochemical sediment analyses in Kassjön (63°55´ N, 20°01´ E).2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For studies using lake sediments as a medium, understanding factors governing sediment distribution and properties is crucial for making accurate interpretations and conclusions. General lake sedimentation theory is however mainly based on larger lakes and systems, potentially leading to biased sampling and data interpretation when applied on a smaller system. In a paper published in 2008, Rippey et al. evaluated the fit of some general sedimentation theories on element distribution in the sediments of Kassjön (63°55´ N, 20°01´ E), northern Sweden. This small boreal lake reoccurs in the scientific literature, largely from paleolimnological studies on varved sediments in the lake, making the understanding of its sediment properties highly relevant. As part of a wider geochemical study on the lake, this paper scrutinizes the findings of Rippey et al. (2008) by using updated bathymetry and geochemical analyses, to provide further insight on sedimentation in Kassjön. Element composition, analysed with X-ray fluorescence spectrometry, and dry weight was obtained from sediment samples at 40 sites. Depth at sampling sites, together with catchment morphometry and previous bathymetry, was used to improve the bathymetric understanding. Kassjön was found to have a less steep bathymetry than previously assumed, with distribution of sediment geochemistry and dry weight showing heterogeneity differing from that expected of general sedimentation theories only. These results indicate that previous findings on sedimentation in Kassjön might be too simplistic, and that small-lake sedimentation is influenced by factors not included in general sedimentation models. Caution is therefore advised when e.g. interpreting the environmental record in lake sediments.

  • 17.
    Helmersson, Alexandra
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Vattenskydd och krisberedskap hos allmän dricksvattenproduktion: Skydd av täkter, tillgång till reservvattentäkter och andra nödvattenlösningar hos svenska vattenproducenter2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this report was to analyse and compare vulnerability and preparation in Swedish municipal drinking water production, in case the commonly used water sources were inoperative. Methods used were a questionnaire and a less extensive study of regulations for water protection areas. The questionnaire was answered by 41 Swedish municipalities. A handful of them were companies co-owned by a few municipalities. Only one out of four municipalities had source protection areas to all their water sources and for many sources the protection was not satisfactory. Two municipalities in the study had no water sources of their own. Instead they bought all their drinking water from a company. This was considered an element of risk. It was also considered risky to have only a few water sources of the same type (groundwater or surface water). In this case it is extra important that there are other ways to prepare and deliver water. Half of the municipalities in the study had a substitute water source but an evaluation found half of these water sources deficient in at least one perspective. There were mainly three reasons why some municipalities did not have a water source substitute. These reasons were financial limitations, difficulties finding a water source with enough capacity and that the preparation had been found adequate without a water source substitute. The last argument was the most common and has occasionally been found accurate. One third of all the municipalities were still inadequately prepared for possible emergencies affecting water production.

  • 18.
    Horstkotte, Tim
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Moen, Jon
    Lämås, Tomas
    Helle, Timo
    The legacy of logging-estimating arboreal lichen occurrence in a boreal multiple-use landscape on a two century scale2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 12, e28779- p.Article in journal (Refereed)
    Abstract [en]

    In northern Sweden, the availability of arboreal lichens (Bryoria fuscescens, Alectoria sarmentosa) as winter grazing resources is an important element in reindeer husbandry. With the industrialization of forestry, forests rich in arboreal lichens have diminished considerably. Here, we analyze how forestry has impacted lichen availability from the 1920's to the present day and model its future development assuming different forest management scenarios. We recorded the current occurrence of B. fuscescens in 144 sampling plots, stratified by forest age class and dominant tree species in a 26,600 ha boreal forest landscape that is used for both reindeer herding and forestry. Lichen abundance was visually estimated in four classes: none, sparse, moderate and abundant. A binary logistic model using forest age as the independent variable was developed to predict the probability of lichens being present. Using this model, we found that lichens were present in stands that are at least 63 years old. Because of the relative paucity of stands rich in arboreal lichens, it was not possible to reliably determine how age affects the variation in abundance of older forest stands. The historical development of forests where arboreal lichens could potentially occur was studied using historic forestry records dating back 80 years. Between 1926 and the present day, forestry has reduced the cover of forests older than 60 years from 84% to 34%. The likely future spatial coverage of these stands over the next 120 years was estimated for two different management scenarios and an unmanaged reference scenario, using the Heureka strategic planning program. Under both the "business as usual'' scenario and that involving more intensive forestry, continued decreases in lichen availability are projected. Our results emphasize the importance of alternative forestry practices, such as prolonged rotation periods, to increase the availability of arboreal lichens as a grazing resource for reindeer.

  • 19. Jiang, Tao
    et al.
    Skyllberg, Ulf
    Björn, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Green, Nelson W.
    Tang, Jianhui
    Wang, Dingyong
    Gao, Jie
    Li, Chuxian
    Characteristics of dissolved organic matter (DOM) and relationship with dissolved mercury in Xiaoqing River-Laizhou Bay estuary, Bohai Sea, China2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 223, 19-30 p.Article in journal (Refereed)
    Abstract [en]

    Abstract Because of heterogeneous properties, dissolved organic matter (DOM) is known to control the environmental fate of a variety of organic pollutants and trace metals in aquatic systems. Here we report absorptive and fluorescence properties of DOM, in concurrence with concentrations of dissolved mercury (Hg), along the Xiaoqing River-Laizhou Bay estuary system located in the Bohai Sea of China. A mixing model consisting of the two end-members terrestrial and aquatic DOM demonstrated that terrestrial signatures decreased significantly from the river into the estuary. Quasi-conservative mixing behavior of DOM sources suggests that the variations in the average DOM composition were governed by physical processes (e.g., dilution) rather than by new production and/or degradation processes. In contrast to some previous studies of river-estuary systems, the Xiaoqing River-Laizhou Bay estuary system displayed a non-significant correlation between DOM and Hg quantities. Based on this and the variation of Hg concentration along the salinity gradient, we concluded that Hg showed a non-conservative mixing behavior of suggested end-member sources. Thus, rather than mixing, Hg concentration variations seemed to be controlled by biogeochemical processes.

  • 20.
    Johansson, Eva
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Samband mellan vulkanutbrott och klimatförändringar: Analys och värdering av teorier om vulkanisk aska och gasers påverkan på det globala klimatet2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This literature review analyses and discusses different theories and results regarding impact of volcanic eruptions on climate change in Earth's history. Present global warming has been attributed to anthropogenic emissions of greenhouse gases, mainly carbon dioxide, however changes in global temperatures have occurred before the onset of anthropogenic emissions. Certain prehistoric climate changes are thought to be caused by emissions of volcanic gases to the atmosphere. Many studies have investigated the connection between volcanic events and subsequent changes in global temperatures. A majority have concluded that volcanic sulfur dioxide is the main direct and indirect climate forcing gas influencing temperatures over time. Increased volcanic activity over the last 15 years is thought to be an inhibiting factor on present global warming. This is supported by evidence of past volcanic events preceding global cooling and warming periods during Holocene and prehistoric times. Further, there are indications that factors such as geographical position, season, gas composition, magnitude and duration of an eruption influences the extent of the climate forcing.Records of climate such as ice cores and tree growth rings and isotopic characterization have made it possible to identify volcano eruptions over time and determine the identity of the erupting volcano. Past and present data from these can be used to gain a better understanding of past climate changes as well as making predictions about future changes as a result volcanic eruptions. However, accuracy regarding temporal and spatial resolution of these records is of great importance for the validity of the results.

  • 21. Johansson, Therese
    et al.
    Andersson, Jon
    Hjältén, Joakim
    Dynesius, Mats
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ecke, Frauke
    Short-term responses of beetle assemblages to wildfire in a region with more than 100 years of fire suppression2011In: Insect Conservation and Diversity, ISSN 1752-458X, Vol. 4, no 2, 142-151 p.Article in journal (Refereed)
    Abstract [en]

    1. Suppression of wildfires in boreal landscapes has become widespread and has seriously affected many fire favoured species. However, little is known about the response of organism assemblages to large wildfires in regions with a long history of effective fire suppression, such as Scandinavia.

    2. We studied the short-term effects of a >1600 ha wildfire on beetle assemblages in northern Sweden. The first summer after fire, beetles were sampled in 12 sites using 36 large window traps, half in old pine forest stands in the burned area and half in similar, but unburned control stands. The entire beetle assemblage and eight subgroups were analysed: saproxylics, non-saproxylics, moderately fire favoured, strongly fire favoured, fungivores, predators, cambium consumers and red-listed species.

    3. Species composition differed markedly between burned and unburned forests in all nine groups. Furthermore, beetle abundance was higher in the burned area for the entire assemblage and for saproxylics, both groups of fire favoured species, predators and cambium consumers. Species number was higher only for non-saproxylics, strongly fire favoured species and cambium consumers.

    4. Our results show that wildfire has rapid and strong effects on a wide range of beetles. However, we only trapped two individuals of fire-dependent beetles, which may suggest a lack of such species in the region, possibly due to >100 years of fire suppression. At the regional scale, the studied wildfire may potentially increase the abundance of these beetles after a longer period of reproduction in the burned area.

  • 22.
    Jonsson, Sofia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Tracing late Holocene changes in lake-water total organic carbon: A multi-proxy approach based on sediment bio-geochemistry and a faecal biomarker2015Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Long-term dynamics of lake-water total organic carbon (LW-TOC) concentrations in freshwater lakes provide an important perspective on the recent increases in LW-TOC observed in many of these systems and may assist with the identification of natural and anthropogenic drivers of change. This study examines how LW-TOC in Dragsjön, a lake situated in an area with a long history of anthropogenic land use, has changed in response to natural and anthropogenic perturbations throughout the Holocene. To provide a better understanding of the processes involved, a multi-proxy study was conducted and included multi-element geochemistry (17 major and trace elements), biogenic silica, organic matter (OM) content and composition, and the faecal biomarker “coprostanol”. The direct biomarker for anthropogenic presence, “coprostanol”, and a detailed characterisation of OM composition are for the first time applied for tracing changes in LW-TOC. Natural processes contributed to stable LW-TOC concentrations in Dragsjön for most part of the Holocene. Humans were present in the catchment from AD 100 as indicated by coprostanol, but did not begin to affect LW-TOC until c. AD 1500. In the last 500 years LW-TOC steadily declined from 17 to 10 mg L-1 in response to anthropogenic alterations to the terrestrial biomass balance. The increase in LW-TOC during the last 70 years likely represents a recovery from anthropogenic disturbance rather than a baseline shift in response to any of the number of proposed recent stressors. The faecal biomarker coprostanol and OM composition provided information essential for identifying and characterising the effects of anthropogenic disturbance.

  • 23.
    Kampezidou, Dimitra
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Spatial distribution of heavy metals in surface marine sediments in the Mediterranean region2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Several scientific articles were mainly reviewed from Umeå’ s university database in order to determine the distribution, degree of contamination, and the sources of 7 selected heavy metals (Cr, Pb, Cu, Zn, Cd, Hg, Ni) in surface sediments along the coasts of the Mediterranean Sea. The Enrichment factor (EF) was used as pollution indicator to evaluate the extent of metal contamination in all the investigated areas. According to Abrahim and Parker (2008) the EF is defined as the ratio of the determined metal to Al (or Fe) in the sample divided by the ratio of background metal to background Al (or Fe) ratio. According to the results of this study, EF values for Cr, Pb, Cu, Cd and Ni presented an upward trend along the west to east shoreline of the Mediterranean sea, whereas Zn and Hg EF values showed a downward trend along this region. Cr generally exhibited no enrichment in places to the west (EF<1.5) whereas in the eastern side displayed moderate enrichment (EF=1.95). Pb EF values showed moderate enrichment (EF=5) along the western section of the sea, whilst in the eastern part revealed significant enrichment (5.45). Zn pollution levels were minimal (EF=1.6) in places to the west and moderate (EF=2.2) to the east. The enrichment for Cd was considered moderate in the western part of the basin and significant in the eastern section. These heavy metals distribution can be explained by the fact that different inputs (mainly due to anthropogenic activities) from the inshore environment may take place in each area of the sea. However, Cu and Ni presented the same degree of pollution (moderate) in the whole sea, presumably indicating similar Cu and Ni inputs from the terrestrial environment. However, conclusions for Hg were not possible to be drawn as the collected data were not sufficient. 

    The full text will be freely available from 2021-01-01 09:00
  • 24.
    Keskitalo, E. Carina H.
    et al.
    Umeå University, Faculty of Social Sciences, Department of Geography and Economic History.
    Pettersson, Maria
    Umeå University, Faculty of Social Sciences, Department of Geography and Economic History.
    Can Adaptation to Climate Change at All Be Mainstreamed in Complex Multi-level Governance Systems?: A Case Study of Forest-Relevant Policies at the EU and Swedish Levels2016In: IMPLEMENTING CLIMATE CHANGE ADAPTATION IN CITIES AND COMMUNITIES: INTEGRATING STRATEGIES AND EDUCATIONAL APPROACHES, CHAM: Springer International Publishing , 2016, 53-74 p.Conference paper (Refereed)
    Abstract [en]

    Mainstreaming adaptation to climate change in forest-relevant policy can be as a "most difficult" case, relevant for asking the question to extent to which adaptation can at all be mainstreamed in complex multi-level governance systems. This study examines the case of to what extent EU and national (exemplified by Swedish) legal and policy frameworks are able to integrate with each other in ways that may support climate change adaptation in forests. To move as close to the real life situation of mainstreaming challenges as possible, the study focuses on not only one area of mainstreaming or integration, but on the three broad policy areas: (a) adaptation per se; (b) forest biodiversity and habitat protection with respect to invasive species; and (c) water protection in relation to forest use. The study concludes that conflicts between international legal principles such as precaution and free trade, as well as distribution of competences at EU and national level, results in a great discrepancy in terms of opportunities for a nation to effectively act independently as well as for effectively integrating adaptation aims in the connected EU-national systems.

  • 25.
    Kilpatrick, Douglas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    The effects of population growth on Ecosystem services in lake Ekoln: A multi-proxy data analysis of a lake core and historical records.2016Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Throughout human history man has utilized the environment to varying degrees, depending on technology and population. These ¨ecosystem services¨ have suffered sustained degradation over the centuries, resulting in large investments having to be made to prevent and reverse further changes to the environment. Few studies have attempted to quantitatively compare how these changes, occurring long before modern environmental monitoring programs started, affected important ecosystem services such as species diversity, water quality, carbon burial and soil stability. The aims of this study were to i) assess whether human impact on ecosystem services have varied over time in perspective of relative change, and ii) to assess the individual (per capita) contributions. I used multiple sediment proxies from a 6 m C¹⁴-dated core collected from lake Ekoln, South-Central Sweden, to reconstruct environmental changes while tracking the population growth in the city of Uppsala during the last ten centuries. Through the use of pollen and diatom assemblages I reconstructed the changing terrestrial and aquatic diversities over time, while sediment accumulation rates and the X-ray fluorescence spectroscopy of the sediment was used to reconstruct soil stability, carbon burial and water quality, respectively. In the latter case, sediment phosphorus concentrations were used as a proxy for freshwater eutrophication while metals (mercury and lead) were used to infer inputs of toxic pollutants. Finally, I normalized (z) all data to create meta-data. The z-values and reconstructed population for Uppsala made it possible to differentiate 5 unique time periods based on anthropogenic induced change, which were not previously visible in the data, and all of which have been linked to the most likely historical causes, including the Black Death. The results show that the most significant anthropogenic impacts in terms of pollution volume occurred in the 1960s, while the period from 1200-1500 AD saw the most significant environmental change in terms per head of capita, most likely caused by the shift from woodland to open landscape through twiddening, a process of burning forest to create agricultural land, prior to 1500 AD. Moreover, rapid recovery is visible after the implementation of environmental policies from the 1970s onwards.

  • 26. Kuba, Matthias
    et al.
    He, Hanbing
    Kirnbauer, Friedrich
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ohman, Marcus
    Hofbauer, Hermann
    Deposit build-up and ash behavior in dual fluid bed steam gasification of logging residues in an industrial power plant2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 139, 33-41 p.Article in journal (Refereed)
    Abstract [en]

    A promising way to substitute fossil fuels for production of electricity, heat, fuels for transportation and synthetic chemicals is biomass steam gasification in a dual fluidized bed (DFB). Using lower-cost feedstock, such as logging residues, instead of stemwood, improves the economic operation. In Senden, near Ulm in Germany, the first plant using logging residues is successfully operated by Stadtwerke Ulm. The major difficulties are slagging and deposit build-up. This paper characterizes inorganic components of ash forming matter and draws conclusions regarding mechanisms of deposit build-up. Olivine is used as bed material. Impurities, e.g., quartz, brought into the fluidized bed with the feedstock play a critical role. Interaction with biomass ash leads to formation of potassium silicates, decreasing the melting temperature. Recirculation of coarse ash back into combustion leads to enrichment of critical fragments. Improving the management of inorganic streams and controlling temperature levels is essential for operation with logging residues. (C) 2015 Elsevier B.V. All rights reserved.

  • 27.
    Kullman, Leif
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Treeline (Pinus sylvestris) landscape evolution in the Swedish Scandes - a 40-year demographic effort viewed in a broader temporal context2014In: Norsk Geografisk Tidsskrift, ISSN 0029-1951, E-ISSN 1502-5292, Vol. 68, no 3, 155-167 p.Article in journal (Refereed)
    Abstract [en]

    The article reports the outcome of long-term demographic monitoring of elevational treeline ecotonal stands of Scots pine (Pinus sylvestris L.) in the southern Swedish Scandes. Annual censuses were undertaken of recruitment, mortality, growth, seed viability, and causes of mortality during the period 1973-2012 in a set of 18 permanent plots. A net gain in total population size occurred over the study period as the result of periodic fluctuations in recruitment and mortality, broadly congruent with annual variations in summer and winter temperatures. Summer temperatures affected seed viability, establishment, and height growth. Winter temperatures exerted an impact foremost by changing the incidence of winter desiccation injury. As a result of infilling, pine has become a more prominent and vital component of the landscape around the forest limit, which has advanced insignificantly into the bordering mountain birch forest. The results highlight a rigid climate-forest disequilibrium and falsify models suggesting extensive and swift expansion of the treeline ecotone and closed forest at the expense of alpine tundra in response to anticipated future warming during the present century. The balance of evidence suggests that patchy forest expansion is likely to occur at a very slow (plurisecular) pace, given that climate warming prevails.

  • 28.
    Larsson, Cecilia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    The importance of winter for carbon emissions from boreal lakes2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this study was to investigate the importance of winter season for the production of carbon dioxide (CO2) and methane (CH4) in humic and clear-water boreal aquatic systems. The study was conducted in 16 experimental ponds in northern Sweden during the winter of 2013. Half of the ponds had a higher concentration of dissolved organic carbon (DOC). CO2, CH4, DOC and dissolved inorganic carbon (DIC) were measured repeatedly under the ice from January to April. The results show that CO2 was accumulated continually during winter. No difference in winter accumulation were found between humic and clear ponds. CH4 was rarely accumulated in neither humic nor clear ponds, and was not an important part of the gas flux at spring ice melt. At ice melt, the flux from humic ponds accounted for 1.6 g C m-2 and 1.7 g C m-2 from clear ponds, which was equivalent for 15.6% respective 100% of the annual gas emissions. On a whole-year basis humic ponds acted as a source of 10.3 g C m-2, while clear ponds acted as a sink of 14.7 g C m-2. 76 mg m-2 d-1 DOC was consumed in humic and 59 mg m-2 d-1 DOC in clear ponds while the DIC accumulation was 125 mg m-2 d-1 in humic and 118 mg m-2 d-1 in clear ponds. This study stresses the importance of ice-covered boreal aquatic systems as a significant parts of the global carbon cycling.

  • 29.
    Lehman, Hanna
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Assuandammens påverkan på Nilen, Egypten2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Regulation of rivers by dams and reservoirs is a good example where anthropogenic impact could be considerable both in the local environment, but also has major implications upstream and downstream. This study was accomplished as a literature study of the river Nile, which is extremely important for water supply. The purpose of this study was to investigate the consequences of the construction of the Aswan High Dam, to obtain a consistent flow for water supply, irrigation and power generation in Egypt. Since Egypt has a very hot and dry climate large amounts of water in reservoir is lost to the Nubian aquifer system and by evaporation. The consequences from constructing the dam are considerable. It has led to the preventing of the annual flooding and a significant reduction in sediment load reaching the outer delta, which has led to an erosion of the delta front. The incoming waves create a current, mainly towards the east, carrying away the eroded material. In order to protect the delta front seawalls and breakwaters has been built. They have stopped the erosion of the areas behind them, but it has also led to the erosion of other areas.

    The issues in Egypt reflect the global crisis, mainly in delta areas, which prevail in regulated rivers. The biggest issue globally is the reduced sediment transport to the coast that causes land loss. 

  • 30. Lenoir, Jonathan
    et al.
    Graae, Bente Jessen
    Aarrestad, Per Arild
    Alsos, Inger Greve
    Armbruster, W. Scott
    Austrheim, Gunnar
    Bergendorff, Claes
    Birks, H. John B.
    Brathen, Kari Anne
    Brunet, Jorg
    Bruun, Hans Henrik
    Dahlberg, Carl Johan
    Decocq, Guillaume
    Diekmann, Martin
    Dynesius, Mats
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ejrnaes, Rasmus
    Grytnes, John-Arvid
    Hylander, Kristoffer
    Klanderud, Kari
    Luoto, Miska
    Milbau, Ann
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Moora, Mari
    Nygaard, Bettina
    Odland, Arvid
    Ravolainen, Virve Tuulia
    Reinhardt, Stefanie
    Sandvik, Sylvi Marlen
    Schei, Fride Hoistad
    Speed, James David Mervyn
    Tveraabak, Liv Unn
    Vandvik, Vigdis
    Velle, Liv Guri
    Virtanen, Risto
    Zobel, Martin
    Svenning, Jens-Christian
    Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe2013In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 19, no 5, 1470-1481 p.Article in journal (Refereed)
    Abstract [en]

    Recent studies from mountainous areas of small spatial extent (<2500km2) suggest that fine-grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate-change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine-grained thermal variability across a 2500-km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000-m2 units (community-inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1-km2 units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1-km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100-km2 units. Ellenberg temperature indicator values in combination with plant assemblages explained 4672% of variation in LmT and 9296% of variation in GiT during the growing season (June, July, August). Growing-season CiT range within 1-km2 units peaked at 6065 degrees N and increased with terrain roughness, averaging 1.97 degrees C (SD=0.84 degrees C) and 2.68 degrees C (SD=1.26 degrees C) within the flattest and roughest units respectively. Complex interactions between topography-related variables and latitude explained 35% of variation in growing-season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing-season CiT within 100-km2 units was, on average, 1.8 times greater (0.32 degrees Ckm1) than spatial turnover in growing-season GiT (0.18 degrees Ckm1). We conclude that thermal variability within 1-km2 units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains.

  • 31.
    Lidberg, William
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Deglaciationen av ett område på västra Grönland: Deglaciationen av ett område på västra Grönland2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this report is to describe the deglaciation in an area on west Greenland in the vicinity of Kangerlussuaq. To do this, the geomorphological landforms were mapped by studying areal photographs and by a two week field study where key areas were examiend. The landforms were transferred to a map using ArcGis and each key area were interpreted.The majority of the geomorphological formations were formed during the last deglaciation and consists of morain ridges, kettle topography in both till and glacifluvium, glacifluvial deltas, two fossil sandurs, and lateral terraces. Based on key areas and an inversion model a geomorphological map was created to illustrate the deglaciation, using the least complex explanation of the genesis of the landforms. The results show that the ice played a major role by damming lakes which enabled formation of many meltwater chanels and delta formations on higher elevations. The morain ridges and lateral terraces showed the extent of the ice margin during the halts in the ice retreat. The deglaciation was dated with help from earlier studies and the conclusion was that the deglaciation started between 7900 and 6700 yr BP. And the area was free from ice 7100-6500 yrs BP.

  • 32.
    Linda, Engström
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Effects of forestry on stream water chemistry during autumn: A before and after comparison between a reference and two streams with clear-cut watershed areas2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Forestry is a large-scale business in many countries, and in northern Sweden a large portion of the Boreal forests is cut. Yet very few studies have investigated the impacts of forestry on the vast number of receiving stream waters. This study has therefore investigated the impacts of forestry, through clear-cutting, on stream water chemistry during autumn conditions in northern Sweden. The study compares the parameters water height, absorbance, dissolved organic carbon, total dissolved nitrogen and total phosphorus in two inlet streams in recently deforested sites, <1 year ago, and an undisturbed reference inlet stream. The disturbed inlet streams are compared to the reference inlet stream the year before and after clear-cutting. This study shows that during a 15- day period from late August to the beginning of September, water height was increased in both disturbed inlet streams, indicative of a higher run-off post-harvest. Absorbance showed a large decrease post-harvest in the disturbed inlet streams. Total dissolved nitrogen and total phosphorus concentrations decreased slightly after clear-cut in both disturbed inlet streams. The effect was probably larger for phosphorus, since the seasonal variation in the reference was larger in 2013. DOC concentrations increased slightly in one of the disturbed inlet streams in 2013, but decreased slightly in the other disturbed inlet stream. The increased run-off was therefore not followed by a higher DOC and nutrient leakage. Results suggest that during a short period in the autumn, harvest does not seem to lead to increased DOC and nutrient losses to receiving stream waters.

  • 33.
    Lundström, Manda
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Miljöteknisk markundersökning på misstänkt förorenad grustäkt i Ytterhogdal2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 34.
    Macphail, Richard I
    et al.
    UCL.
    Bill, Jan
    Universitetsmuseet Oslo.
    Cannel, Rebecca
    Universitetsmuseet Oslo.
    Linderholm, Johan
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Rødsrud, Christian
    Universitetsmuseet Oslo.
    Integrated microstratigraphic investigations of coastal archaeological soils and sediments in Norway: the Gokstad ship burial mound and its environs including the Viking harbour settlement of Heimdaljordet, Vestfold2013In: Quaternary International, ISSN 1040-6182, Vol. 315, 131-146 p.Article in journal (Refereed)
    Abstract [en]

    Investigations of past coastal landscape development have included soil micromorphology, chemistry and microfossil recording of soils and sediments associated with marine inundation and terrestrial soil formation in marine sediments. This paper reports on similarly studied site formation processes at Norwegian coastal sites in Vestfold, Norway: the Viking Period Gokstad Ship Burial Mound and nearby contemporary harbour site of Heimdaljordet. At Gokstad, strategically-focused coring revealed mound composition and an example of its buried soil and geology. The latter investigation suggested that post glacial uplift led to a ‘slowstand’ period of intertidal reworking of till before ∼700 BC emergence and development of terrestrial soils. At Heimdaljordet, typically laminated intertidal silty clay loam sediments were sealed by beach sands, into which, for example, a boat grave was dug. Post-depositional processes affecting the Gokstad Mound were compared to those in other mounds, including those recorded in experimental earthworks. Waterlogged conditions in the Gokstad mound led to iron–phosphate migration and preferential deposition of vivianite in turf layers where relict litter (L) layers remained visible, and where wood chips from constructional activities are also very well preserved (as is the long ship itself). These soil insights and other paleoenvironmental studies of the buried soil and numerous turf sequences showed that the contemporary AD 900 Viking landscape was totally terrestrial. It had become wet sedge grassland managed for grazing. The partial weathering of turves and anomalous presence within them of ‘fresh’ roots apparently indicates the possibility that turves were stacked and stored ahead of mound building. The 10th C robber trench had developed muddy features, and rooting traces show that it was not backfilled, but was slowly infilled by humic soil silting from turf mound layers. This event did not affect the overall anaerobic burial conditions in the mound, which can be starkly compared to those at the Heimdaljordet boat grave. Here, because of acidic subaerial weathering, the wooden boat only survives as an acidic pellety humus formed of wood residues that are often ferruginised. Iron appears to be concentrated at iron nail locations. Unlike the Gokstad mound, no bone survives, but one sample found a typical ‘body stain’ of secondary iron and phosphate close by the iron encrusted sword in the grave (potentially the pelvic region of the inhumation). Here, mineralised faecal gut remains have an assumed hydroxyapatite composition, and embed phytoliths and pollen/spores, as found in human coprolites and cess deposits studied elsewhere.

  • 35.
    Meyer-Jacob, Carsten
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Tolu, Julie
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bigler, Christian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Yang, Handong
    Environmental Change Research Centre, University College London, London WC1E 6BT, United Kingdom.
    Bindler, Richard
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Early land use and centennial scale changes in lake-water organic carbon prior to contemporary monitoring2015In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 21, 6579-6584 p.Article in journal (Refereed)
    Abstract [en]

    Organic carbon concentrations have increased in surface waters across parts of Europe and North America during the past decades, but the main drivers causing this phenomenon are still debated. A lack of observations beyond the last few decades inhibits a better mechanistic understanding of this process and thus a reliable prediction of future changes. Here we present past lake-water organic carbon trends inferred from sediment records across central Sweden that allow us to assess the observed increase on a centennial to millennial time scale. Our data show the recent increase in lake-water carbon but also that this increase was preceded by a landscape-wide, long-term decrease beginning already A. D. 1450-1600. Geochemical and biological proxies reveal that these dynamics coincided with an intensification of human catchment disturbance that decreased over the past century. Catchment disturbance was driven by the expansion and later cessation of widespread summer forest grazing and farming across central Scandinavia. Our findings demonstrate that early land use strongly affected past organic carbon dynamics and suggest that the influence of historical landscape utilization on contemporary changes in lake-water carbon levels has thus far been underestimated. We propose that past changes in land use are also a strong contributing factor in ongoing organic carbon trends in other regions that underwent similar comprehensive changes due to early cultivation and grazing over centuries to millennia.

  • 36.
    Muthreich, Florian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Effect of historical land-use on lake-water carbon and geochemistry:: A multi-proxy study of two lake sediment profiles in Dalarna throughout the Holocene2016Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    This study examines changes in lake-water total organic carbon (LW-TOC) and lake sediment geochemistry in two lakes, Stångtjärnen and Holtjärnen in (Dalarna, Sweden), during the Holocene and the role of the historic forest grazing and farming (fäbod-system). The aims of the study were to: 1. Discern the effects of natural processes on the lake’s biogeochemistry in different position in the landscape. 2. Identify the effects and differences in intensity of historic land-use on the lakes. A multi-proxy study was conducted encompassing multi-element (15) geochemistry, biogenic silica, LW-TOC, chlorophyll a and published pollen records. The first lake, Stångtjärnen, is shaped and influenced by surrounding mires, which developed shortly after deglaciation and stabilized the LW-TOC at 19 mg L-1 throughout most of the Holocene, while Holtjärnen, a small upland lake, changed from a productive lake (BSi: 35 %), low humic (LW-TOC: 8 mg L-1) to a less productive (BSi: 4 %) more humic lake (LW-TOC: 12 mg L-1) in 7300 BP. The intensification of agricultural land-use (e.g. hay-making) in Stångtjärnen reduced the concentrations of organic associated elements (Br, Cl) and LW-TOC and increased lithogenic elements (K, Ti), while Holtjärnen showed less anthropogenic influence. The comparison between the two lakes displayed the intensive influence of land-use on the Stångtjärnen catchment, showcased by changes in the sediment geochemistry, vegetation composition and the extent of the forest-grazing system in a landscape perspective. In response to the changes of the Holocene, Stångtjärnen’s mires became the main influence, while Holtjärnen was more sensitive to changes. 

  • 37.
    Myrstener, Maria
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Konduktivitet i vattendrag som indikator på sura sulfatjordar2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Increasing attention is being given to acid sulphate soils wherever they occur. The problems that leaching sulphate soils gives with significant lowerings of pH and mobilization of heavy metals influence large spectra of our society from fisheries to agriculture to construction. Mapping these soils is consequently of great importance and the methods of doing this is very much lacking in function and precision. This study was therefore carried out to investigate whether conductivity in running water can be used as a simple instrument to identify acid sulphate soils in the catchment. 31 coastal streams in the county of Västerbotten were analyzed for different catchment properties such as occurence of marine sediments and basic water chemistry including conductivity and sulphate. Sulphate proved to be the dominant factor controling conductivity in most streams, constituting up to 90 % of the anions. The results also showed that the concentrations of sulphate correlated to 67 % with marine sediments in the catchment. Where conductivity values exceeded 90 µS/cm the influence of acid sulphate soils could be determined for certain. The major conclusion drawn from this study is that high conductivity values serves as a reliable indicator of leaching acid sulphate soils whereas lower values can not exclude them.

  • 38.
    Mårald, Erland
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Langston, Nancy
    Michigan Technological University, Houghton, MI, USA.
    Sténs, Anna
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Moen, Jon
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Changing ideas in forestry: A comparison of concepts in Swedish and American forestry journals during the early twentieth and twenty-first centuries2016In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 45, 74-86 p.Article in journal (Refereed)
    Abstract [en]

    By combining digital humanities text-mining tools and a qualitative approach, we examine changing concepts in forestry journals in Sweden and the United States (US) in the early twentieth and early twenty-first centuries. Our first hypothesis is that foresters at the beginning of the twentieth century were more concerned with production and less concerned with ecology than foresters at the beginning of the twenty-first century. Our second hypothesis is that US foresters in the early twentieth century were less concerned with local site conditions than Swedish foresters. We find that early foresters in both countries had broader—and often ecologically focused—concerns than hypothesized. Ecological concerns in the forestry literature have increased, but in the Nordic countries, production concerns have increased as well. In both regions and both time periods, timber management is closely connected to concerns about governance and state power, but the forms that governance takes have changed.

  • 39.
    Nordin, Marcus
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Kan marin sand och grus utgöra ett subtitut för landbaserade naturgrustäkter?: En undersökning utanför Umeås kust2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sand and gravel are compounds that are directly needed in the fine fraction of making concrete. Concrete is used as a foundation in 90 % of the cases when establishing new buildings in Sweden. Usually, sand and gravel are taken from land based areas. These land based areas with sand and gravel are also needed for the cleaning of the groundwater. Groundwater is the source of drinking water in big parts of Sweden and should therefore not be jeopardized. In the marine environment, there are areas that possess sand and gravel that could be used instead of land based material, and therefore will not jeopardize the quality of drinking water. By learning how the law is regulated in marine sand and gravel extraction cases, looking at existing maps of the marine geology’s structure, learning about the environmental impacts and by looking at the technique that are used for extracting the material of the bottom of the ocean - this report shows the possibilities of marine sand and gravel extraction of the ocean floor outside of Umeå’s coastline. The result shows that there are a few areas that have the right material and lies on the right depth of the ocean floor, but these areas did not have the right thickness. Therefore, an extraction of marine sand and gravel at these areas (Area A and B) would affect the volume percentage. This could lead to a change of the bottom structure that destroys the recovery after the extraction and damage the marine environment. 

  • 40.
    Ortuno, Nuria
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lundstedt, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lundin, Lisa
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Emissions of PBDD/Fs, PCDD/Fs and PBDEs from flame-retarded high-impact polystyrene under thermal stress2015In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 123, 64-70 p.Article in journal (Refereed)
    Abstract [en]

    The emissions of polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and their chlorinated analogues (PCDD/Fs) during the thermal treatment of a high impact polystyrene (HIPS) TV casing were investigated. The halogenated compounds were analyzed in the original material and in the gases emitted during its treatment at temperatures between 50 degrees C and 250 degrees C. DecaBDE was the primary PBDE in the TV casing, which also contained high levels of PBDFs (ppm range). At the lower treatment temperatures, non-modified PBDEs evaporated from the samples. Conversely, at 200 degrees C or above, debromination reactions led to the formation of additional tri- through nonaBDE. The formation of new PBDD/Fs was also detected in the gas phase when the plastic was heated to 200 degrees C or 250 degrees C, with higher yields of furans than dioxins. This appreciably increased the toxic equivalent (TEQ) levels of the gas phase relative to those seen in the untreated sample. In all cases, the levels and TEQ contributions from PCDD/Fs were negligible compared to those for brominated analogues. (C) 2014 Elsevier Ltd. All rights reserved.

  • 41.
    Renquist, Dan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rotnedträngning i skydds- och tätskikt på nedlagda anrikningssandsmagasin2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 42.
    Riström, Emilia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Siktning som saneringsmetod för metallförorenad mark2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Toxic metals contaminate soil worldwide and thus serve as sever environmental threat. Therefore the purposes of this study were to investigate in which soil fractions that different heavy metals (Fe, As, Cu, Zn and Pb) could be found in contaminated soils and if it is possible to use sieving as a method for decontamination. Soil samples were collected from three different locations, the Nasa silver mine, the Blaiken-mine and Svalget environmental station. The samples were oven dried and later on sieved into six different fractions 8mm, 4 mm, 0.5 mm, 0.250mm, 0.063 mm and <0.063 mm. The fractions 4 mm, 0.5 mm and <0.063 mm from each location were analyzed in an x-ray fluorescence detector. The results showed that in general the smallest fractions contained the highest concentration of heavy metals which was very clear for Pb where 5 out of 6 samples had the highest concentration in the smallest fraction. The highest concentration of Cu (1147 ppm) and Zn (1117 ppm) were found in the smallest fraction in samples from the location Svalget. The highest concentration of Pb (10042 ppm) was also found in the smallest fraction in samples from Blaiken. In similarity the highest concentration of As (13305 ppm) was found in the smallest fraction in samples from the Nasa mine. However, in most samples the difference between the smallest fractions and the coarser material was small. Sieving may therefore not be the best way to decontaminate soil because even the larger fractions contained high concentrations of heavy metals.

  • 43.
    Rybacka, Aleksandra
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ruden, Christina
    Tetko, Igor V.
    Andersson, Patrik L.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Identifying potential endocrine disruptors among industrial chemicals and their metabolites - development and evaluation of in silico tools2015In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 139, 372-378 p.Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to improve the identification of endocrine disrupting chemicals (EDCs) by developing and evaluating in silico tools that predict interactions at the estrogen (E) and androgen (A) receptors, and binding to transthyretin (T). In particular, the study focuses on evaluating the use of the EAT models in combination with a metabolism simulator to study the significance of bioactivation for endocrine disruption. Balanced accuracies of the EAT models ranged from 77-87%, 62-77%, and 65-89% for E-, A-, and T-binding respectively. The developed models were applied on a set of more than 6000 commonly used industrial chemicals of which 9% were predicted E- and/or A-binders and 1% were predicted T-binders. The numbers of E- and T-binders increased 2- and 3-fold, respectively, after metabolic transformation, while the number of A-binders marginally changed. In-depth validation confirmed that several of the predicted bioactivated E- or T-binders demonstrated in vivo estrogenic activity or influenced blood levels of thyroxine in vivo. The metabolite simulator was evaluated using in vivo data from the literature which showed a 50% accuracy for studied chemicals. The study stresses, in summary, the importance of including metabolic activation in prioritization activities of potentially emerging contaminants. 

  • 44.
    Rydberg, Johan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rosen, Peter
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lambertsson, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    De Vleeschouwer, F
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Tomasdotter, S
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bindler, Richard
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Assessment of the spatial distributions of total- and methyl-mercury and their relationship to sediment geochemistry from a whole-lake perspective2012In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 117, G04005- p.Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to determine the spatial variability for total-and methylmercury in surface sediments (0-2 cm) across a single whole-lake basin, and to relate this variability to the sediment's geochemical composition. 83 surface sediment samples from Stor-Stromsjon - a lake with multiple sub-basins located in northern Sweden - were analyzed for geochemical composition as well as total-mercury (total-Hg) and methylmercury (methyl-Hg; 35 samples) concentrations. Our results indicate that variations in fine-grained mineral matter (36%) and organic matter (34%) explain an equal amount of the total-Hg variation, but that their relative importance varies between different parts of the lake. Total-Hg concentrations were similar in locations controlled by organic matter or fine-grained mineral matter (average 109 ng g(-1)); however, total-Hg inventories (mass per unit area) were significantly higher in the latter (35 and 53 mu g m(-2), respectively). Methyl-Hg concentrations are largely (55% of variance) controlled by water depth and sulfur concentration, which supports the importance of within lake methylation reported from other studies. Both for concentrations and inventories the spatial distribution for methyl-Hg in surface sediments is patchy, and interestingly the highest methyl-Hg inventory (1.4 mu g m(-2)) was found in a shallow location with coarse-grained minerogenic sediment (very low organic matter). A large spatial variability, even within a single lake, is something that needs to be recognized, e.g., when studying processes affecting mercury cycling, mercury loadings and when using lake sediments to reconstruct historic mercury deposition.

  • 45. Shtangeeva, Irina
    et al.
    Tesfalidet, Solomon
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Comparison of nutrient concentrations in leaves of five plants2017In: Journal of plant nutrition, ISSN 0190-4167, E-ISSN 1532-4087, Vol. 40, no 2, 239-247 p.Article in journal (Refereed)
    Abstract [en]

    The paper describes investigation on bioaccumulation of mineral elementsand identification of plants based on the concentrations of the elements inthe plant leaves. Five native plant species (Elytrigia repens, Plantago major,Urtica dioica, Chelidonium majus, and Taraxacum officinale) were studied. Toexclude the effects from different growth conditions and developmentalstages, the plants were collected simultaneously from the same site (park inSt. Petersburg, Russia). It was found that for all plants high concentrations ofpotassium, sodium, phosphorus and magnesium (K, Na, P, and Mg) weretypical, while concentrations of zinc (Zn) and copper (Cu) were the lowest.The most significant difference was found between concentrations ofelements in monocots and eudicots. Among other species,T. officinalehadthe highest concentrations of almost all elements. Excellent separation of theplants into different groups which was due to different elementconcentrations in the plant leaves was demonstrated.

  • 46.
    Tarberg, Martin
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Utsläpp av växthusgaser under islossning i små boreala sjöar2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Freshwater ecosystems have long been neglected as an important part of the global carbon cycle. However, research shows that most of the world’s lakes are net-heterotrophic and consequently emitters of greenhouse gases to the atmosphere. In many boreal and north-temperate lakes, most of the yearly emissions usually occur in spring, shortly after ice-thaw. The aim of this study was to quantify the flux of carbon dioxide (CO2) and methane (CH4) in three boreal lakes, during this annual event. In order to do this, water samples were collected before and after ice-thaw, and the flux was estimated as the difference in mass of carbon between the two sampling occasions. The results showed that the lakes had accumulated high amounts of carbon over the winter, with higher concentrations generally at higher depths. The fluxes during ice-thaw ranged from 234–380 (mean: 302) and -1.15–15.12 (mean: 8.64) mmol m-2 y-1 for CO2 and CH4, respectively. Given their small sizes, the lakes emitted less carbon, per unit area, than expected. This was assumed to be due to the lakes’ rather isolated locations and since the heating of the water rapidly caused them to become highly stratified, thus preventing the wind from releasing deeper stored carbon. Presumably, this holds true for other similar boreal lakes as well, which suggests that attention – in such ecosystems – also needs to be brought to other mixing periods.

  • 47.
    Tolu, Julie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gerber, Lorenz
    Boily, Jean-Francois
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bindler, Richard
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    High-throughput characterization of sediment organic matter by pyrolysis-gas chromatography/mass spectrometry and multivariate curve resolution: A promising analytical tool in (paleo) limnology2015In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 880, 93-102 p.Article in journal (Refereed)
    Abstract [en]

    Molecular-level chemical information about organic matter (OM) in sediments helps to establish the sources of OM and the prevalent degradation/diagenetic processes, both essential for understanding the cycling of carbon (C) and of the elements associated with OM (toxic trace metals and nutrients) in lake ecosystems. Ideally, analytical methods for characterizing OM should allow high sample throughput, consume small amounts of sample and yield relevant chemical information, which are essential for multidisciplinary, high-temporal resolution and/or large spatial scale investigations. We have developed a high-throughput analytical method based on pyrolysis-gas chromatography/mass spectrometry and automated data processing to characterize sedimentary OM in sediments. Our method consumes 200 mg of freeze-dried and ground sediment sample. Pyrolysis was performed at 450 degrees C, which was found to avoid degradation of specific biomarkers (e. g., lignin compounds, fresh carbohydrates/cellulose) compared to 650 degrees C, which is in the range of temperatures commonly applied for environmental samples. The optimization was conducted using the top ten sediment samples of an annually resolved sediment record (containing 16-18% and 1.3-1.9% of total carbon and nitrogen, respectively). Several hundred pyrolytic compound peaks were detected of which over 200 were identified, which represent different classes of organic compounds (i. e., n-alkanes, n-alkenes, 2-ketones, carboxylic acids, carbohydrates, proteins, other N compounds, (methoxy) phenols, (poly) aromatics, chlorophyll and steroids/hopanoids). Technical reproducibility measured as relative standard deviation of the identified peaks in triplicate analyses was 5.5 +/- 4.3%, with 90% of the RSD values within 10% and 98% within 15%. Finally, a multivariate calibration model was calculated between the pyrolytic degradation compounds and the sediment depth (i. e., sediment age), which is a function of degradation processes and changes in OM source type. This allowed validation of the Py-GC/MS dataset against fundamental processes involved in OM cycling in aquatic ecosystems.

  • 48. Valinia, Salar
    et al.
    Futter, Martyn N.
    Cosby, Bernard J.
    Rosen, Peter
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Folster, Jens
    Simple Models to Estimate Historical and Recent Changes of Total Organic Carbon Concentrations in Lakes2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 1, 386-394 p.Article in journal (Refereed)
    Abstract [en]

    Quantifying human impacts on the natural environment requires credible reconstructions of reference conditions. Anthropogenic acidification of surface waters is strongly influenced by total organic carbon (TOC) concentrations. Because both the degree of acidification and recovery are dependent on historical TOC concentrations, simple models to estimate changes in surface water TOC between reference conditions (1860) and the present day (2012) are needed. We used visible near infrared spectroscopy (VNIRS) of lake sediments to reconstruct reference condition TOC and long-term monitoring data to predict recent changes. Two empirical models were developed to predict: (i) historical TOC trends between reference conditions (1860) and peak acidification (1980) and (ii) trends in TOC between 1988 and 2012. The models were statistically robust with adj. R(2) of (i) 0.85 and (ii) 0.71, respectively. Models were driven by lake and catchment area, wetlands, historical sulfur deposition and water chemistry. Present day TOC concentrations are similar to VNIRS-reconstructed and modeled reference condition TOC in Swedish lakes. The results are valuable for understanding drivers of TOC changes in lakes and for more credible assessments of reference conditions needed for water management in Europe and elsewhere.

  • 49.
    Vinterek, Sebastian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rening av lakvatten vid deponin Degermyran i Skellefteå kommun: Utvärdering av nuvarande reningseffekt och simulering av mängden bildat lakvatten under 2000-talets klimatförändringar2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    At Degermyran landfill, situated in the municipal Skellefteå, a leachate treatment system was installed in 2005. One of the aims of this study was to investigate how well the treatment system works by using data from chemical measurements made on the leachate before and after treatment. Further this study had the purpose of investigating how the predicted climate changes of the 21st century will affect the amount of leachate generated at Degermyran by using a modified version of Thornthwaites water balance model. The treatment system has the ability of reducing manganese by 90 %, nitrogen by 73 % och TOC by 79 %. By the turn of this century the amount of precipitation that percolates the waste at Degermyran will be between 254 and 298 mm, depending on the amount of greenhouse gases that will be released in the future to come. The conclusions from this study are that the leachate treatment system reduces the levels of the investigated substances and that the amount of leachate produced at Degermyran will increase. To further investigate the efficiency of the leachate treatment system, flow proportionate measurements of the leachate chemistry could be adopted. If accurate flow measurements of the amount of generated leachate were performed the reliability of the used water balance model could be assessed.

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