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  • 1.
    Bastviken, David
    et al.
    Stockholm University.
    Sandén, Per
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ståhlberg, Carina
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Magounakis, Malin
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences.
    Chloride retention and release in a boreal forest soil: effects of soil water residence time and nitrogen and chloride loads2006In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 40, no 9, p. 2977-2982Article in journal (Refereed)
    Abstract [en]

    The common assumption that chloride (Cl-) is conservative in soils and can be used as a groundwater tracer is currently being questioned, and an increasing number of studies indicate that Cl- can be retained in soils. We performed lysimeter experiments with soil from a coniferous forest in southeast Sweden to determine whether pore water residence time and nitrogen and Cl- loads affected Cl- retention. Over the first 42 days there was a net retention of Cl- with retention rates averaging 3.1 mg Cl- m-2 d-1 (68% of the added Cl- retained over 42 days). Thereafter, a net release of Cl- at similar rates was observed for the remaining experimental period (85 d). Longer soil water residence time and higher Cl- load gave higher initial retention and subsequent release rates than shorter residence time and lower Cl- load did. Nitrogen load did not affect Cl transformation rates. This study indicates that simultaneous retention and release of Cl- can occur in soils, and that rates may be considerable relative to the load. The retention of Cl- observed was probably due to chlorination of soil organic matter or ion exchange. The cause of the shift between net retention and net release is unclear, but we hypothesize that the presence of O2 or the presence of microbially available organic matter regulates Cl- retention and release rates.

  • 2.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Susanne
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sandén, Per
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    IRES, UBC, Canada.
    Temperature sensitivity indicates enzyme controlled chlorination of soil organic matter2009In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, no 10, p. 3569-3573Article in journal (Refereed)
    Abstract [en]

    Old assumptions that chloride is inert and that most chlorinated organic matter in soils is anthropogenic have been challenged by findings of naturally formed organochlorines. Such natural chlorination has been recognized for several decades, but there are still very few measurements of chlorination rates or estimates of the quantitative importance of terrestrial chlorine transformations. While much is known about the formation of specific compounds, bulk chlorination remains poorly understood in terms of mechanisms and effects of environmental factors. We quantified bulk chlorination rates in coniferous forest soil using 36Cl-chloride in tracer experiments at different temperatures and with and without molecular oxygen (O2). Chlorination was enhanced by the presence of O2 and had a temperature optimum at 20 °C. Minimum rates were found at high temperatures (50 °C) or under anoxic conditions. The results indicate (1) that most of the chlorination between 4 and 40 °C was biotic and driven by O2 dependent enzymes, and (2) that there is also slower background chlorination occurring under anoxic conditions at 20 °C and under oxic conditions at 50 °C. Hence, while oxic and biotic chlorination clearly dominated, chlorination by other processes including possible abiotic reactions was also detected.

  • 3.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sandén, Per
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Kylin, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Chlorine cycling and fates of 36Cl in terrestrial environments2013Report (Other academic)
    Abstract [en]

    Chlorine-36 (36Cl), a radioisotope of chlorine (Cl) with a half-life of 301,000 years, is present in some types of nuclear waste and is disposed in repositories for radioactive waste. As the release of 36Cl from such repositories to the near surface environment has to be taken into account it is of interest to predict possible fates of 36Cl under various conditions as a part of the safety assessments of repositories for radioactive waste. This report aims to summarize the state of the art knowledge on Cl cycling in terrestrial environments. The view on Cl cycling in terrestrial environments is changing due to recent research and it is clear that the chloride ion (Cl) is more reactive than previously believed. We group the major findings in three categories below according to the amount of data in support of the findings.

    From the result presented in this report it is evident that:

    • There is an ubiquitous and extensive natural chlorination of organic matter in terrestrial ecosystems.
    • The abundance of naturally formed chlorinated organic compounds (Clorg) frequently exceeds the abundance of Cl, particularly in soils. Thereby Clorg in many cases dominates the total Cl pool.
    • This has important implications for Cl transport. When reaching surface soils Cl will not be a suitable tracer of water and will instead enter other Cl pools (Clorg and biomass) that prolong residence times in the system.
    • Cl dominates import and export from terrestrial ecosystems while Clorg and biomass Cl can dominate the standing stock Cl within terrestrial ecosystems.
    • Both Cl and Clorg pools have to be considered separately in future monitoring programs addressing Cl cycling.

    Further, there are also indications (in need of confirmation by additional studies) that:

    • There is a rapid and large uptake of Cl by organisms and an accumulation in green plant parts. A surprisingly large proportion of total catchment Cl (up to 60%) can be found in the terrestrial biomass.
    • Emissions of total volatile organohalogens could be a significant export pathway of Cl from the systems.
    • Some of the Clorg may be very persistent and resist degradation better than average organic matter. This may lead to selective preservation of some Clorg (with associated low bioavailability).
    • There is a production of Clorg in tissues of e.g. plants and animals and Cl can accumulate as
    • chlorinated fatty acids in organisms.

    Most other nevertheless important aspects are largely unknown due to lack of data. Key unknowns include:

    • The development over time of major Cl pools and fluxes. As long as such data is lacking we cannot assess net changes over time.
    • How the precesses behind chlorination, dechlorination and transport patterns in terrestrial systems are regulated and affected by environmental factors.
    • The ecological roles of the chlorine cycling in general.
    • The ecological role of the microbial chlorination in particular.
    • The chlorine cycling in aquatic environments – including Cl and Clorg pools in sediment and water, are largely missing.

    Given the limited present information available, and particularly the lack of data with a temporal dimension and the lack of process understanding, predictive models are challenging. We also summarize currently available methods to study Cl in the environment.

  • 4.
    Bastviken, David
    et al.
    Department of geology and geochemistry Stockholm University.
    Thomsen, Frida
    The Tema institute Linköpings universitet.
    Svensson, Teresia
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Karlsson, Susanne
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Shaw, George
    Division of agricultural and environmental sciences University of Nottingham.
    Matucha, Miroslav
    Institute of experimental botany Ac. Sci. Czech Rep.
    Öberg, Gunilla
    Institute for resources, environment and sustainability University of British Colombia.
    Chloride retention in forest soil by microbial uptake and by natural chlorination of organic matter2007In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 71, no 13, p. 3182-3192Article in journal (Refereed)
    Abstract [en]

    Inorganic chlorine (i.e. chloride, Clin) is generally considered inert in soil and is often used as a tracer of soil and ground water movements. However, recent studies indicate that substantial retention or release of Clin can occur in soil, but the rates and processes responsible under different environmental conditions are largely unknown. We performed 36Cl tracer experiments which indicated that short-term microbial uptake and release of Clin, in combination with more long-term natural formation of chlorinated organic matter (Clorg), caused Clin imbalances in coniferous forest soil. Extensive microbial uptake and release of Clin occurred over short time scales, and were probably associated with changes in environmental conditions. Up to 24% of the initially available Clin within pore water was retained by microbial uptake within a week in our experiments, but most of this Clin was released to the pore water again within a month, probably associated with decreasing microbial populations. The natural formation of Clorg resulted in a net immobilization of 4% of the initial pore water Clin over four months. If this rate is representative for the area where soil was collected, Clorg formation would correspond to a conversion of 25% of the yearly wet deposition of Clin. The study illustrates the potential of two Clin retaining processes in addition to those previously addressed elsewhere (e.g. uptake of chloride by vegetation). Hence, several processes operating at different time scales and with different regulation mechanisms can cause Clin imbalances in soil. Altogether, the results of the present study (1) provide evidence that Clin cannot be assumed to be inert in soil, (2) show that microbial exchange can regulate pore water Clin concentrations and (3) confirm the controversial idea of substantial natural chlorination of soil organic matter. © 2007 Elsevier Ltd. All rights reserved.

  • 5.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Problem-oriented laboratory work in environmental education: Experiences from a new master´s programme at Linköping Univerity, Sweden1999In: AuDes 5th Conference on Environmental Education, 1999Conference paper (Other academic)
  • 6.
    de Boer, Wietse
    et al.
    Netherlands Institute of Ecology.
    Folman, Larissa B.
    Netherlands Institute of Ecology.
    Klein Gunnewiek, Paulien J.A.
    Netherlands Institute of Ecology.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    del Rio, José C.
    Instituto de Recursos Naturales y Agrobiología de Sevilla.
    Boddy, Lynne
    Cardiff School of Biosciences.
    Mechanism of antibacterial activity of the white-rot fungus Hypholoma fasciculare colonizing wood2010In: Canadian journal of microbiology (Print), ISSN 0008-4166, E-ISSN 1480-3275, Vol. 56, no 5, p. 380-388Article in journal (Other academic)
    Abstract [en]

    In a previous study it was shown that the number of wood-inhabiting bacteria was drastically reduced after colonization of beech (Fagus sylvatica) wood blocks by the white-rot fungus Hypholoma fasciculare, or sulfur tuft (Folman et al. 2008). Here we report on the mechanisms of this fungal-induced antibacterial activity. Hypholoma fasciculare was allowed to invade beech and pine (Pinus sylvestris) wood blocks that had been precolonized by microorganisms from forest soil. The changes in the number of bacteria, fungal biomass, and fungal-related wood properties were followed for 23 weeks. Colonization by the fungus resulted in a rapid and large reduction in the number of bacteria (colony-forming units), which was already apparent after 4 weeks of incubation. The reduction in the number of bacteria coincided with fungal-induced acidification in both beech and pine wood blocks. No evidence was found for the involvement of toxic secondary metabolites or reactive oxygen species in the reduction of the number of bacteria. Additional experiments showed that the dominant bacteria present in the wood blocks were not able to grow under the acidic conditions (pH 3.5) created by the fungus. Hence our research pointed at rapid acidification as the major factor causing reduction of wood-inhabiting bacteria upon colonization of wood by H. fasciculare.

  • 7.
    Gustavsson, Malin
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Karlsson, Susanne
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Oeberg, Gunilla
    University of British Columbia.
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Valinia, Salar
    Swedish University of Agriculture Science.
    Thiry, Yves
    Andra, Chatenay Malabry, France .
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Organic Matter Chlorination Rates in Different Boreal Soils: The Role of Soil Organic Matter Content2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 3, p. 1504-1510Article in journal (Refereed)
    Abstract [en]

    Transformation of chloride (Cl-) to organic chlorine (Cl-org) occurs naturally in soil but it is poorly understood how and why transformation rates vary among environments. There are still few measurements of chlorination rates in soils, even though formation of Cl-org has been known for two decades. In the present study, we compare organic matter (OM) chlorination rates, measured by Cl-36 tracer experiments, in soils from eleven different locations (coniferous forest soils, pasture soils and agricultural soils) and discuss how various environmental factors effect chlorination. Chlorination rates were highest in the forest soils and strong correlations were seen with environmental variables such as soil OM content and Cl- concentration. Data presented support the hypothesis that OM levels give the framework for the soil chlorine cycling and that chlorination in more organic soils over time leads to a larger Cl-org pool and in turn to a high internal supply of Cl- upon dechlorination. This provides unexpected indications that pore water Cl- levels may be controlled by supply from dechlorination processes and can explain why soil Cl- locally can be more closely related to soil OM content and the amount organically bound chlorine than to Cl- deposition.

  • 8.
    Johansson, Emma
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ebenå, Gustav
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Sandén, Per
    Linköping University, Department of Thematic Studies, Environmental Science. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, Department of Thematic Studies, Environmental Science. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Organic and chlorine in Swedish spruce forest soil: Influence of nitrogen2001In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 101, no 3-4, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Concentrations of organic and inorganic chlorine were estimated in samples collected in forest soils in the southern part of Sweden, and changes were observed after the addition of nitrogen in incubated samples. All of the investigated samples contained both inorganic and organic chlorine, and the concentration of organic chlorine was 2-4 times larger than that of inorganic chlorine. The results suggest that the amount of organic chlorine in mature spruce forest soils with a moderate chloride deposition in the temperate region is larger than the amount of inorganic chlorine. The results of the nitrogen incubation indicate that addition of ammonium nitrate causes a net decrease in the concentration of organic chlorine and a net increase in chloride concentration. The observed change appears to mainly be a result of a dechlorination of the organic matter present in the water leachable fraction. © 2001 Elsevier Science B.V.

  • 9.
    Johansson, Madelaine
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, TeresiaLinköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Att lära för det okända: Miljövetarprogrammets jubileumsskrift2009Collection (editor) (Other (popular science, discussion, etc.))
  • 10.
    Johansson, Madelaine
    et al.
    Centre for Academic Development, Karlstad University, Karlstad, Sweden.
    Svensson, Teresia
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Individual Reflection Paper: Supporting Student's Learning in the Critical Phase of Self-directed Learning in PBL2019In: Journal of Problem Based Learning in Higher Education, ISSN 2246-0918, E-ISSN 0974-276XArticle in journal (Refereed)
    Abstract [en]

    Supporting and assessment of students’ preparation and learning process in problem-based learning (PBL) tutorials has long been a challenge. We present a modified PBL model focussing on the specific critical phase in the PBL process, the self-directed learning phase in between tutorial meetings. The modified seven step PBL model including an Individual reflection paper (IRP) is presented as well as students’ perspectives on the implementation of IRP and information literacy, knowledge gathering, and PBL tutorial work. The assessment of PBL work is complex, and the ways in which IRPs support the tutor’s role as an examiner is beyond the scope of the current study. However, it seems that the students experienced assessment of the IRPs as part of their as a positive driving force in their learning process.

  • 11.
    Kylin, Henrik
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Research Unit: Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.
    Svensson, Teresia
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Jensen, Sören
    Stockholm University, Sweden.
    Strachan, William
    Environment and Climate Change Canada, Canada.
    Franich, Robert
    Scion Research, New Zealand.
    Bouwman, Hindrik
    North-West University, South Africa.
    The trans-continental distributions of pentachlorophenol and pentachloroanisole in pine needles indicate separate origins2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 229, p. 688-695Article in journal (Refereed)
    Abstract [en]

    The production and use of pentachlorophenol (PCP) was recently prohibited/restricted by the Stockholm Convention on persistent organic pollutants (POPs), but environmental data are few and of varying quality. We here present the first extensive dataset of the continent-wide (Eurasia and Canada) occurrence of PCP and its methylation product pentachloroanisole (PCA) in the environment, specifically in pine needles. The highest concentrations of PCP were found close to expected point sources, while PCA chiefly shows a northern and/or coastal distribution not correlating with PCP distribution. Although long-range transport and environmental methylation of PCP or formation from other precursors cannot be excluded, the distribution patterns suggest that such processes may not be the only source of PCA to remote regions and unknown sources should be sought. We suggest that natural sources, e.g., chlorination of organic matter in Boreal forest soils enhanced by chloride deposition from marine sources, should be investigated as a possible partial explanation of the observed distributions. The results show that neither PCA nor total PCP (ΣPCP = PCP + PCA) should be used to approximate the concentrations of PCP; PCP and PCA must be determined and quantified separately to understand their occurrence and fate in the environment. The background work shows that the accumulation of airborne POPs in plants is a complex process. The variations in life cycles and physiological adaptations have to be taken into account when using plants to evaluate the concentrations of POPs in remote areas.

    The full text will be freely available from 2019-07-13 15:35
  • 12.
    Laturnus, Frank
    et al.
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Fahimi, Isabelle
    Gryndler, Milan
    Hartmann, Anton
    Heal, Mathew R
    Matucha, Miroslav
    Schöler, Heinz Friedrich
    Schroll, Reiner
    Svensson, Teresia
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Natural formation and degradation of chloroacetic acids and volatile organochlorine compounds in forest soil - Challenges to Understanding2005In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 12, p. 233-244Article in journal (Refereed)
    Abstract [en]

    Goal, Scope and Background. The anthropogenic environmental emissions of chloroacetic acids and volatile organochlorines have been under scrutiny in recent years because the two compound groups are suspected to contribute to forest dieback and stratospheric ozone destruction, respectively. The two organochlorine groups are linked because the atmospheric photochemical oxidation of some volatile organochlorine compounds is one source of phytotoxic chloroacetic acids in the environment. Moreover, both groups are produced in higher amounts by natural chlorination of organic matter, e.g. by soil microorganisms, marine macroalgae and salt lake bacteria, and show similar metabolism pathways. Elucidating the origin and fate of these organohalogens is necessary to implement actions to counteract environmental problems caused by these compounds Main Features. While the anthropogenic sources of chloroacetic acids and volatile organochlorines are relatively well-known and within human control, knowledge of relevant natural processes is scarce and fragmented. This article reviews current knowledge on natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soils, with particular emphasis on processes in the rhizosphere, and discusses future studies necessary to understand the role of forest soils in the formation and degradation of these compounds Results and Discussion. Reviewing the present knowledge of the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil has revealed gaps in knowledge regarding the actual mechanisms behind these processes. In particular, there remains insufficient quantification of reliable budgets and rates of formation and degradation of chloroacetic acids and volatile organochlorines in forest soil (both biotic and abiotic processes) to evaluate the strength of forest ecosystems regarding the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale Conclusion. It is concluded that the overall role of forest soil as a source and/or sink for chloroacetic acids and volatile organochlorines is still unclear; the available laboratory and field data reveal only bits of the puzzle. Detailed knowledge of the natural degradation and formation processes in forest soil is important to evaluate the strength of forest ecosystems for the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale Recommendation and Perspective. As the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil can be influenced by human activities, evaluation of the extent of this influence will help to identify what future actions are needed to reduce human influences and thus prevent further damage to the environment and to human health caused by these compounds

  • 13.
    Laturnus, Frank
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Sandén, Per
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Wiencke, Christian
    AWI, Bremerhafen, Germany.
    Finding the scattered pieces of the mechanisms behind the formation of volatile halogen-containing C1- and C2-compounds in Antarctic macroalgae2008In: Reports on polar and marine research. 571, Alfred-Wegener Institut fur Polar- und Meeresforschung , 2008, p. 200-207Chapter in book (Other academic)
  • 14.
    Laturnus, Frank
    et al.
    Institute for Biogeochemistry and Marine Chemistry, University of Hamburg, Germany.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Wiencke, Christian
    Alfred Wegener Institute for Polar and Marine Research, Germany.
    Release of reactive organic halogens by the brown macroalga Saccharina latissima after exposure to ultraviolet radiation2010In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 29, no 3, p. 379-384Article in journal (Refereed)
    Abstract [en]

    The brown macroalga Saccharina latissima (Linnaeus) C.E. Lane, C. Mayes, Druehl & G.W. Saunders (formerly Laminaria saccharina [L.] Lamouroux) was exposed to ultraviolet radiation (UVR) in the mW UV-A and mW UV-B range in the laboratory for up to 28 days. The release rates of volatile organohalogens, such as chloroform, bromoform, dibromomethane and methyl iodide, were determined. From these rates, the total emission of reactive organic halogens was calculated. The results revealed that exposure to UVR significantly affected the emission of reactive organic halogens by the macroalga under investigation. An increase in the release of reactive organic iodine was observed for the algal species. In contrast, for reactive organic bromine and reactive organic chlorine, a decrease in emission by the macroalga was observed. Apparently, the potential for increased levels of UVR resulting from further ongoing destruction of the stratospheric ozone layer may increase the importance of marine macroalgae in atmospheric reactions involving organic halogens.

  • 15.
    Laturnus, Frank
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Department of Communications Studies, Art and Visual Communication .
    Svensson, Teresia
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies.
    Wiencke, Christian
    Alfred Wegener Institute, Germany.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Ultraviolet radiation affects emission of ozone-depleting substances by marine macroalgae: Results from a laboratory incubation study2004In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 38, no 24, p. 6605-6609Article in journal (Refereed)
    Abstract [en]

    The depletion of stratospheric ozone due to the effects of ozone-depleting substances, such as volatile organohalogens, emitted into the atmosphere from industrial and natural sources has increased the amount of ultraviolet radiation reaching the earth's surface. Especially in the subpolar and polar regions, where stratospheric ozone destruction is the highest, individual organisms and whole ecosystems can be affected. In a laboratory study, several species of marine macroalgae occurring in the polar and northern temperate regions were exposed to elevated levels of ultraviolet radiation. Most of the macroalgae released significantly more chloroform, bromoform, dibromomethane, and methyl iodide-all volatile organohalogens. Calculating on the basis of the release of total chlorine, bromine, and iodine revealed that, except for two macroalgae emitting chlorine and one alga emitting iodine, exposure to ultraviolet radiation caused macroalgae to emit significantly more total chlorine, bromine, and iodine. Increasing levels of ultraviolet radiation due to possible further destruction of the stratospheric ozone layer as a result of ongoing global atmospheric warming may thus increase the future importance of marine macroalgae as a source for the global occurrence of reactive halogencontaining compounds.

  • 16.
    Montelius, Malin
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Lourino-Cabana, Beatriz
    EDF, Laboratoire National d'Hydraulique et Environnement, 78401 Chatou, France.
    Thiry, Yves
    Andra, Research and Development Division, Parc de la Croix Blanche, 1/7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex, Franc.
    Bastviken, David
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Chlorination and dechlorination rates in a forest soil: A combined modelling and experimental approach2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 554-555, p. 203-210Article in journal (Refereed)
    Abstract [en]

    Abstract Much of the total pool of chlorine (Cl) in soil consists of naturally produced organic chlorine (Clorg). The chlorination of bulk organic matter at substantial rates has been experimentally confirmed in various soil types. The subsequent fates of Clorg are important for ecosystem Cl cycling and residence times. As most previous research into dechlorination in soils has examined either single substances or specific groups of compounds, we lack information about overall bulk dechlorination rates. Here we assessed bulk organic matter chlorination and dechlorination rates in coniferous forest soil based on a radiotracer experiment conducted under various environmental conditions (additional water, labile organic matter, and ammonium nitrate). Experiment results were used to develop a model to estimate specific chlorination (i.e., fraction of Cl− transformed to Clorg per time unit) and specific dechlorination (i.e., fraction of Clorg transformed to Cl− per time unit) rates. The results indicate that chlorination and dechlorination occurred simultaneously under all tested environmental conditions. Specific chlorination rates ranged from 0.0005 to 0.01 d− 1 and were hampered by nitrogen fertilization but were otherwise similar among the treatments. Specific dechlorination rates were 0.01–0.03 d− 1 and were similar among all treatments. This study finds that soil Clorg levels result from a dynamic equilibrium between the chlorination and rapid dechlorination of some Clorg compounds, while another Clorg pool is dechlorinated more slowly. Altogether, this study demonstrates a highly active Cl cycling in soils.

  • 17.
    Montelius, Malin
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Thiry, Yves
    Andra, France.
    Marang, Laura
    EDF, France.
    Ranger, Jacques
    INRA Centre Nancy, France.
    Cornelis, Jean-Thomas
    Catholic University of Louvain, Belgium.
    Svensson, Teresia
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Experimental Evidence of Large Changes in Terrestrial Chlorine Cycling Following Altered Tree Species Composition2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 8, p. 4921-4928Article in journal (Refereed)
    Abstract [en]

    Organochlorine molecules (Cl-org) are surprisingly abundant in soils and frequently exceed chloride (Cl-) levels. Despite the widespread abundance of Cl-org and the common ability of microorganisms to produce Cl-org, we lack fundamental knowledge about how overall chlorine cycling is regulated in forested ecosystems. Here we present data from a long-term reforestation experiment where native forest was cleared and replaced with five different tree species. Our results show that the abundance and residence times of Cl- and Cl-org after 30 years were highly dependent on which tree species were planted on the nearby plots. Average Cl- and Cl-org content in soil humus were higher, at experimental plots with coniferous trees than in those with deciduous trees. Plots with Norway spruce had the highest net accumulation of Cl- and Cl-org over the experiment period, and showed a 10 and 4 times higher Cl- and Cl-org storage (kg ha(-1)) in the biomass, respectively, and 7 and 9 times higher storage of Cl- and Cl-org in the soil humus layer, compared to plots with oak. The results can explain why local soil chlorine levels are frequently independent of atmospheric deposition, and provide opportunities for improved modeling of chlorine distribution and cycling in terrestrial ecosystems.

  • 18.
    Pickering, Lauren
    et al.
    University of British Columbia, Vancouver, Canada.
    Black, Andrew
    University of British Columbia, Vancouver, Canada.
    Gilbert, Chanelle
    University of British Columbia, Vancouver, Canada.
    Jeronimo, Matthew
    University of British Columbia, Vancouver, Canada.
    Nesic, Zoran
    University of British Columbia, Vancouver, Canada.
    Pilz, Juergen
    University of Klagenfurt, Klagenfurt, Austria.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    University of British Columbia, Vancouver, Canada.
    Portable Chamber System for Measuring Chloroform Fluxes from Terrestrial Environments – Methodological Challenges2013In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, no 24, p. 14298-14305Article in journal (Refereed)
    Abstract [en]

    This study describes a system designed to measure chloroform flux from terrestrial systems, providing a reliable first assessment of the spatial variability of flux over an area. The study takes into account that the variability of ambient air concentrations is unknown. It includes quality assurance procedures, sensitivity assessments, and testing of materials used to ensure that the flux equation used to extrapolate from concentrations to fluxes is sound and that the system does not act as a sink or a source of chloroform. The results show that many materials and components commonly used in sampling systems designed for CO2, CH4, and N2O emit chloroform and other volatile chlorinated compounds (VOCls) and are thus unsuitable in systems designed for studies of such compounds. To handle the above-mentioned challenges, we designed a system with a non-steady-state chamber and a closed-loop air-circulation unit returning scrubbed air to the chamber. Based on empirical observations, the concentration increase during a deployment was assumed to be linear. Four samples were collected consecutively and a line was fitted to the measured concentrations. The slope of the fitted line and the y-axis intercept were input variables in the equation used to transform concentration change data to flux estimates. The soundness of the flux equation and the underlying assumptions were tested and found to be reliable by comparing modeled and measured concentrations. Fluxes of chloroform in a forest clear-cut on the east coast of Vancouver Island, BC, during the year were found to vary from −130 to 620 ng m–2 h–1. The study shows that the method can reliably detect differences of approximately 50 ng m–2 h–1 in chloroform fluxes. The statistical power of the method is still comparatively strong down to differences of 35 ng m–2 h–1, but for smaller differences, the results should be interpreted with caution.

  • 19.
    Svensson, Teresia
    Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Chlorine Transport in a Small Catchment2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    It is generally known that chlorine compounds are ubiquitous in the environment. In recent years, researchers have concluded that chlorine is part of a biogeochemical cycle in soil involving an interaction between chloride (Clin) and organic-matter-bound chlorine (Clorg). Even though there is indisputable evidence that Clorg is formed naturally, there are actually few simultaneous field measurements of Clorg and Clin. Previously stipulated conclusions with respect to underlying processes and transport estimates have thus been deduced from rather few concentration measurements. It is well known that the chemical composition in soil and runoff water varies widely over time and in space. The main objective of the thesis is to investigate the on-site variation of Clin, Clorg and VOCls in runoff water in order to (i) construct a chlorine budget on a catchment scale to visualize the relative contribution of Clin, Clorg, and VOCls; (ii) more reliably estimate how and why the concentrations of Clin, Clorg, and VOCls in runoff water vary; and (iii) analyze the influence of various environmental variables on the transport.

    The present thesis highlights the on-site variation and fluxes of Clin, Clorg, and VOCls in a small forested catchment in southeast Sweden. Field flux data collected during a twoyear period and a constructed overall chlorine budget were evaluated. The results show that the storage is dominated by Clorg whereas the transport is dominated by Clin and that the storage is far much larger than the transport. Still, input and output is nearly in balance for all investigated chlorine species. It is interesting to note that these observations resemble observations made for carbon, nitrogen and sulphur; i.e. a large storage, small transport, complex biogeochemical cycling processes at hand but still close to steady state conditions with respect to output-input balances. It appears as if topsoil acts as a sink for Clin, while deeper soil acts as a source of Clin. In addition, the results of the thesis suggest that on-site variation depend on seasonal variations. These variations are to some extent caused by water discharge, but also by water residence time, internal chlorination/dechlorination of organic matter, and different soil water origins. Furthermore, both a net retention and a net release of Clin were observed in laboratory studies. The study indicates that simultaneous retention and release of Clin takes place in soil, which probably has an impact on the Clin import and export fluxes. Finally, the results show for the first time that tetrachloromethane can be emitted from laboratory incubated soil, and that soil nitrogen concentrations has quite different effects on the emission rates of chloroform and tetrachloromethane.

    The results of the thesis, considered together with results of previous research, suggest that the turnover of chlorine in soils is extensive and potentially important for chlorine cycling in general, which must be taken into account if one wishes to increase the understanding of the cycling of anthropogenic chlorine compounds in the environment.

    List of papers
    1. The role of organic matter bound chlorine in the chlorine cycle: a case study of the Stubbetorp catchment, Sweden
    Open this publication in new window or tab >>The role of organic matter bound chlorine in the chlorine cycle: a case study of the Stubbetorp catchment, Sweden
    Show others...
    2005 (English)In: Biogeochemistry, ISSN 0168-2563, Vol. 75, no 2, p. 241-269Article in journal (Refereed) Published
    Abstract [en]

    The objective of this study is to construct a balanced chlorine budget for a small forested catchment, focusing on the interaction between chloride (Clinorg) and organic-matter-bound chlorine (Clorg). Data from the actual catchment are combined with secondary data from other sites to elucidate more clearly which parts of the cycle are fairly well known and which are more or less unknown. The budget calculations show that the principal input and output fluxes of Cl in the catchment are inorganic but that the main pool is Clorg in the soil. In addition, the budget calculations suggest that a considerable portion of Clinorg in soil is transformed to Clorg and subsequently leached to deeper soil layers, that net mineralization of Clorg takes place in soil, preferably in deeper soil layers, and that degrading organic matter is a major source of Clinorg in runoff. The loss of Clorg through runoff is small to negligible in relation to other fluxes. It appears as if dry deposition of Clinorg is at risk of being underestimated if Clinorg is assumed to be conservative in soil. The pool of organic-matter-bound chlorine in soil is considerably larger than the annual flux of chloride through the system. The estimates suggest that the amount of Clorg in the upper 40 cm of the soil at the investigated site is approximately twice as large as the Clinorg. Furthermore, the amount of Clorg biomass is small in relation to the occurrence of Clorg in soil. Finally, the estimates indicate that the transport of volatile Clorg from the soil to the atmosphere may influence the chlorine cycle.

    Keywords
    Biogeochemistry, Chloride, Cycling, Organic chlorine
    National Category
    Oceanography, Hydrology and Water Resources
    Identifiers
    urn:nbn:se:liu:diva-13819 (URN)10.1007/s10533-004-7259-9 (DOI)
    Available from: 2006-04-21 Created: 2006-04-21 Last updated: 2018-01-13
    2. Chlorine transport in a small catchment in southeast Sweden during two years
    Open this publication in new window or tab >>Chlorine transport in a small catchment in southeast Sweden during two years
    2007 (English)In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 82, no 2, p. 181-199Article in journal (Refereed) Published
    Abstract [en]

    Previous studies have revealed that chlorine participates in a complex biogeochemical cycle in soil, which suggests that the transport of chloride through catchments may also be influenced. The present study is based on field observations of organic carbon, chloride (Clin), and chlorinated organic carbon (Clorg) in precipitation, soil, and runoff over a 2-year period from a small, forested catchment in southeast Sweden. The study reveals that (1) the soil pool is dominated by Clorg, (2) the input via wet deposition and output of Clin via runoff is 30 times smaller than the total storage of chlorine (Clin + Clorg) in soil, and (3) the transport is dominated by Clin. The organic matter that entered the outlet of the catchment was more chlorinated in the autumn than during the rest of the year, and rain events taking place in low-flow periods had a greater influence on TOC, Clorg, and Clin than did rain events taking place in high-flow periods. The seasonal pattern in combination with the low-flow versus high-flow pattern and previous findings of increasing chlorine-to-carbon ratios with soil depth suggests that the chlorine-to-carbon ratio variation in the leached organic matter is due that water preferentially comes from deeper layers in low-flow conditions. This study provides well-founded estimates of Clorg and Clin storage and fluxes for the studied catchment; however, the processes underlying the observed seasonal Clorg variations and transportation processes need further study.

    Keywords
    Catchment, chloride, chlorine, organic chlorine, soil, water, watershed
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-38911 (URN)10.1007/s10533-006-9062-2 (DOI)46101 (Local ID)46101 (Archive number)46101 (OAI)
    Note

    The previous status of this article was Manuscript.

    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13Bibliographically approved
    3. Chloroform in runoff water: a two-year study in a small catchment in southeast Sweden
    Open this publication in new window or tab >>Chloroform in runoff water: a two-year study in a small catchment in southeast Sweden
    2007 (English)In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 82, no 2, p. 139-151Article in journal (Refereed) Published
    Abstract [en]

    Chloroform concentrations were observed and input and output fluxes estimated over a 2-yr period in a small coniferous catchment (0.22 km2) in southeast Sweden. Water discharge was measured daily, and runoff water was sampled bi-weekly for chloroform analysis. An approximate chloroform budget was calculated, which indicated that the annual output of 6 μg m−2 yr−1 was approximately six times higher than the input, inferring an internal source of chloroform in the catchment. To the best of our knowledge, neither flux estimates nor mass balances have previously been made for chloroform on a catchment scale, nor have data regarding natural runoff variation with time been gathered. Concentrations of chloroform in runoff were found to be generally high during wet periods, such as spring, but also peaked during summer rain events. The observed pattern suggests that chloroform is formed in surface soil layers and transported to the outlet under high-flow conditions and during dry-period rain events; it is lost through degradation or evaporation during drier periods due to longer soil water residence times. The data suggest that the variation among replicates increases with concentration; this emphasizes the need to know what the degree of on-site variation is, so one can collect a sufficient number of replicates to permit detection of spatial or temporal changes.

    Keywords
    Biogeochemistry, Catchment, Chloroform, Water, VOCl
    National Category
    Oceanography, Hydrology and Water Resources
    Identifiers
    urn:nbn:se:liu:diva-13821 (URN)10.1007/s10533-006-9059-x (DOI)
    Available from: 2006-04-21 Created: 2006-04-21 Last updated: 2018-01-13Bibliographically approved
    4. Chloride retention and release in a boreal forest soil: effects of soil water residence time and nitrogen and chloride loads
    Open this publication in new window or tab >>Chloride retention and release in a boreal forest soil: effects of soil water residence time and nitrogen and chloride loads
    Show others...
    2006 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 40, no 9, p. 2977-2982Article in journal (Refereed) Published
    Abstract [en]

    The common assumption that chloride (Cl-) is conservative in soils and can be used as a groundwater tracer is currently being questioned, and an increasing number of studies indicate that Cl- can be retained in soils. We performed lysimeter experiments with soil from a coniferous forest in southeast Sweden to determine whether pore water residence time and nitrogen and Cl- loads affected Cl- retention. Over the first 42 days there was a net retention of Cl- with retention rates averaging 3.1 mg Cl- m-2 d-1 (68% of the added Cl- retained over 42 days). Thereafter, a net release of Cl- at similar rates was observed for the remaining experimental period (85 d). Longer soil water residence time and higher Cl- load gave higher initial retention and subsequent release rates than shorter residence time and lower Cl- load did. Nitrogen load did not affect Cl transformation rates. This study indicates that simultaneous retention and release of Cl- can occur in soils, and that rates may be considerable relative to the load. The retention of Cl- observed was probably due to chlorination of soil organic matter or ion exchange. The cause of the shift between net retention and net release is unclear, but we hypothesize that the presence of O2 or the presence of microbially available organic matter regulates Cl- retention and release rates.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-13822 (URN)10.1021/es0523237 (DOI)
    Available from: 2006-04-21 Created: 2006-04-21 Last updated: 2018-10-05Bibliographically approved
    5. Influence of nitrogen on the release of volatile organochlorines from coniferous forest soil: a laboratory study
    Open this publication in new window or tab >>Influence of nitrogen on the release of volatile organochlorines from coniferous forest soil: a laboratory study
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:liu:diva-13823 (URN)
    Available from: 2006-04-21 Created: 2006-04-21 Last updated: 2010-01-13
  • 20.
    Svensson, Teresia
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Högbom, Lars
    Skogforsk, Uppsala, Sweden.
    Johansson, Karin
    Skogforsk, Svalöv, Sweden.
    Ring, Eva
    Skogforsk, Uppsala, Sweden.
    Effects of previous nitrogen addition on chlorine in forest soil, soil solution and biomass2013In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 116, no 1-3, p. 3-13Article in journal (Refereed)
    Abstract [en]

    There is increasing evidence that forests and forest soil contribute to the signature of chlorine composition in water bodies. However, little is known about the potential effects of land management activities on chlorine biogeochemistry. This study examines the effects of previous nitrogen addition on chlorine chemistry in a Pinus sylvestris L. forest located in south-central Sweden (60°00′N, 13°43′E). Repeated addition of nitrogen to study plots over a 20-year period resulted in total additions of 0, 450 and 900 kg N ha−1. Soil samples were collected before harvesting, and soil solution and biomass were sampled following final felling. Contrary to previous findings, we found no clear evidence that previous addition of nitrogen had hampered the formation of organic chlorine in the organic soil layer. We suggest that the effects of nitrogen addition on chlorination processes are not seen in the surface soil, but are instead manifested in the migration of organic matter in the mineral soil. Soil organic matter from the E-horizon had a lower chlorination degree in the nitrogen-amended plots than in the control plots. In addition, we observed lower Cl levels in the seedling needles following high nitrogen fertilization (900 N) than in 450 N or control. These results add on the importance of studying chlorine dynamics with focus on what chlorinated soil organic matter can be resistant to degradation compared to average soil organic matter and what can be leached as a result of harvesting and available for vegetation.

  • 21.
    Svensson, Teresia
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Johansson, Madelaine
    Pedagogiska enheten, Örebro Universitet.
    Miljövetenskaplig undervisning i högre utbildning2016In: Pedagogik för högskolelärare / [ed] Thomas Hansson, Möklinta: Gidlunds förlag, 2016, p. 262-288Chapter in book (Other academic)
    Abstract [sv]

    Det finns didaktiska utmaningar och möjligheter relaterade till ett tvärdisciplinärtämnesområde som det miljövetenskapliga. En central fråga är hur miljövetenskapligutbildning kan utformas för att ge studenterna förutsättningaratt handskas med komplexa, idag möjligen okända, miljöfrågor i en kommandeyrkesverksamhet. I en svensk definition av didaktik är frågeorden Vad, Huroch Varför är centrala, vad bör en miljövetenskaplig utbildning innehålla,hur ska undervisningen genomföras och varför organiseras den som den gör?Det miljövetenskapliga ämnets framväxt har skapat läraktiviteter såsom: case,rollspel, debatt, och projekt. Alla har olika syfte vad gäller bearbetning av innehålloch färdighetsträning. Verklighetsanknuten undervisning är ett viktigt målinom det miljövetenskapliga utbildningsområdet och genom en genomtänktdesign kan studenterna få stöd för lärande inför de arbetsuppgifter de kommeratt möta i teori och i praktik.

  • 22.
    Svensson, Teresia
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Johansson, Madelaine
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Asplund, Therese
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Interdisciplinary Environmental Science in problem-based learning:  introducing complexity to students2011In: Celebrating the Past and Embracing the Future:  Evolution and Innovation in Problem-based Learning: Past & Embracing the Future Conference - 30th - 31st March 2011, 2011Conference paper (Other academic)
  • 23.
    Svensson, Teresia
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Laturnus, Frank
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences.
    Sandén, Per
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Institute for Resources, Environment and Sustainability, Faculty of Graduate Studies, University of British Columbia, Aquatic Ecosystem Research Laboratory, Vancouver, BC, Canada.
    Chloroform in runoff water: a two-year study in a small catchment in southeast Sweden2007In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 82, no 2, p. 139-151Article in journal (Refereed)
    Abstract [en]

    Chloroform concentrations were observed and input and output fluxes estimated over a 2-yr period in a small coniferous catchment (0.22 km2) in southeast Sweden. Water discharge was measured daily, and runoff water was sampled bi-weekly for chloroform analysis. An approximate chloroform budget was calculated, which indicated that the annual output of 6 μg m−2 yr−1 was approximately six times higher than the input, inferring an internal source of chloroform in the catchment. To the best of our knowledge, neither flux estimates nor mass balances have previously been made for chloroform on a catchment scale, nor have data regarding natural runoff variation with time been gathered. Concentrations of chloroform in runoff were found to be generally high during wet periods, such as spring, but also peaked during summer rain events. The observed pattern suggests that chloroform is formed in surface soil layers and transported to the outlet under high-flow conditions and during dry-period rain events; it is lost through degradation or evaporation during drier periods due to longer soil water residence times. The data suggest that the variation among replicates increases with concentration; this emphasizes the need to know what the degree of on-site variation is, so one can collect a sufficient number of replicates to permit detection of spatial or temporal changes.

  • 24.
    Svensson, Teresia
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Lovett, Gary
    Cary Institute of Ecosyste Studies, Millbrook, NY, USA.
    Likens, Gene E
    Cary Institute of Ecosyste Studies, Millbrook, NY, USA.
    Is chloride a conservative ion in forest ecosystems?2012In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 107, no 1-3, p. 125-134Article in journal (Refereed)
    Abstract [en]

    Chloride (Cl-) has often been assumed to be relatively unreactive in forest ecosystems, and is frequently used as a conservative tracer to calculate fluxes of water and other ions. Recently, however, several studies have detailed cycling of Cl- in vegetation and soils. In this study Cl- budgets are compiled from 32 catchment studies to determine the extent to which Cl- is conserved in the passage through forest ecosystems. Chloride budgets from these sites vary from net retention (input/output) to net release (output/input). In the overall data set, including those sites with very high inputs of seasalt Cl-, there was a strong correspondence between inputs and outputs. However, sites with low Cl- deposition (<6 kg ha-1 year-1) consistently showed net release of Cl-, suggesting an internal source or a declining internal pool. The results indicate that Cl- may be a conservative ion in sites with high Cl- deposition, but in sites with low deposition Cl- may not be conservative. We discuss the possible causes of the Cl- imbalance and reasons why Cl- may not be conservative in ecosystem functions.

  • 25.
    Svensson, Teresia
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Montelius, Malin
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Andersson, Malin
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Lindberg, Cecilia
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Reyier, Henrik
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rietz, Karolina
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Danielsson, Åsa
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Influence of Multiple Environmental Factors on Organic Matter Chlorination in Podsol Soil2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 24, p. 14114-14123Article in journal (Refereed)
    Abstract [en]

    Natural chlorination of organic matter is common in soils. The abundance of chlorinated organic compounds frequently exceeds chloride in surface soils, and the ability to chlorinate soil organic matter (SOM) appears widespread among microorganisms. Yet, the environmental control of chlorination is unclear. Laboratory incubations with Cl-36 as a Cl tracer were performed to test how combinations of environmental factors, including levels of soil moisture, nitrate, chloride, and labile organic carbon, influenced chlorination of SOM from a boreal forest. Total chlorination was hampered by addition of nitrate or by nitrate in combination with water but enhanced by addition of chloride or most additions including labile organic matter (glucose and maltose). The greatest chlorination was observed after 15 days when nitrate and water were added together with labile organic matter. The effect that labile organic matter strongly stimulated the chlorination rates was confirmed by a second independent experiment showing higher stimulation at increased availability of labile organic matter. Our results highlight cause-effect links between chlorination and the studied environmental variables in podsol soil-with consistent stimulation by labile organic matter that did overrule the negative effects of nitrate.

  • 26.
    Svensson, Teresia
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies.
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies.
    Bastviken, David
    Department of geology and geochemistry Stockholm, Sweden University.
    Öberg, Gunilla
    Institute for resources, environment and sustainability University of British Colombia, Canada.
    Chlorine transport in a small catchment in southeast Sweden during two years2007In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 82, no 2, p. 181-199Article in journal (Refereed)
    Abstract [en]

    Previous studies have revealed that chlorine participates in a complex biogeochemical cycle in soil, which suggests that the transport of chloride through catchments may also be influenced. The present study is based on field observations of organic carbon, chloride (Clin), and chlorinated organic carbon (Clorg) in precipitation, soil, and runoff over a 2-year period from a small, forested catchment in southeast Sweden. The study reveals that (1) the soil pool is dominated by Clorg, (2) the input via wet deposition and output of Clin via runoff is 30 times smaller than the total storage of chlorine (Clin + Clorg) in soil, and (3) the transport is dominated by Clin. The organic matter that entered the outlet of the catchment was more chlorinated in the autumn than during the rest of the year, and rain events taking place in low-flow periods had a greater influence on TOC, Clorg, and Clin than did rain events taking place in high-flow periods. The seasonal pattern in combination with the low-flow versus high-flow pattern and previous findings of increasing chlorine-to-carbon ratios with soil depth suggests that the chlorine-to-carbon ratio variation in the leached organic matter is due that water preferentially comes from deeper layers in low-flow conditions. This study provides well-founded estimates of Clorg and Clin storage and fluxes for the studied catchment; however, the processes underlying the observed seasonal Clorg variations and transportation processes need further study.

  • 27.
    Svensson, Teresia
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Wibeck, Victoria
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Att bedöma sig själv och andra: Erfarenheter från själv- och kamratvärdering på Miljövetarprogrammet vid Linköpings universitet2008In: Om examination och lärande / [ed] Urban Ljungquist Martin Stigmar Eva Thorin, Växjö: Universitetspedagogiskt centrum, Växjö universitet , 2008, p. 101-112Chapter in book (Other academic)
  • 28.
    Svensson, Teresia
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Öberg, Gunilla
    Linköping University, Department of Thematic Studies.
    Klorets biogeokemiska kretslopp i marken2004In: Markdagen,2004, 2004, p. 33-41Conference paper (Other academic)
  • 29.
    Öberg, Gunilla
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Holm, Mats
    Skogsvårdsstyrelsen Norrköpings distrikt.
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Svensson, Teresia
    Linköping University, The Tema Institute.
    Parikka, Matti
    Institutionen för bioenergi Sveriges lantbruksuniversitet.
    Chlorine budget of a small catchment2004In: European Geosciences Union 1st Assembly,2004, 2004, p. 180-180Conference paper (Other academic)
  • 30.
    Öberg, Gunilla
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Holm, Mats
    Local Forest Administration, Östergötland, Sweden.
    Sandén, Per
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Parikka, Matti
    Department of Bioenergy, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    The role of organic matter bound chlorine in the chlorine cycle: a case study of the Stubbetorp catchment, Sweden2005In: Biogeochemistry, ISSN 0168-2563, Vol. 75, no 2, p. 241-269Article in journal (Refereed)
    Abstract [en]

    The objective of this study is to construct a balanced chlorine budget for a small forested catchment, focusing on the interaction between chloride (Clinorg) and organic-matter-bound chlorine (Clorg). Data from the actual catchment are combined with secondary data from other sites to elucidate more clearly which parts of the cycle are fairly well known and which are more or less unknown. The budget calculations show that the principal input and output fluxes of Cl in the catchment are inorganic but that the main pool is Clorg in the soil. In addition, the budget calculations suggest that a considerable portion of Clinorg in soil is transformed to Clorg and subsequently leached to deeper soil layers, that net mineralization of Clorg takes place in soil, preferably in deeper soil layers, and that degrading organic matter is a major source of Clinorg in runoff. The loss of Clorg through runoff is small to negligible in relation to other fluxes. It appears as if dry deposition of Clinorg is at risk of being underestimated if Clinorg is assumed to be conservative in soil. The pool of organic-matter-bound chlorine in soil is considerably larger than the annual flux of chloride through the system. The estimates suggest that the amount of Clorg in the upper 40 cm of the soil at the investigated site is approximately twice as large as the Clinorg. Furthermore, the amount of Clorg biomass is small in relation to the occurrence of Clorg in soil. Finally, the estimates indicate that the transport of volatile Clorg from the soil to the atmosphere may influence the chlorine cycle.

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