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  • 1.
    Abrandt Dahlgren, Madeleine
    et al.
    Linköping University, Department of Behavioural Sciences.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Questioning to learn and learning to question: Structure and function of problem-based learning scenarios in environmental science education2001In: Higher Education, ISSN 0018-1560, E-ISSN 1573-174X, Vol. 41, no 3, p. 263-282Article in journal (Refereed)
    Abstract [en]

    In problem-based learning, scenarios relating to real life are used as a point of departure for the learning process. Even though the importance of suitable cases or scenarios in bringing about a fruitful learning process is emphasised in the literature, few studies focus on how they actually function in the learning process. This study focuses on how the scenarios used in a ten-week introductory course of a new four-year undergraduate programme in environmental science functioned in terms of the structure and content of the questions they evoked. Data were gathered through diary notes from nine groups of students, comprising 5-8 students per group. The data were subjected to a qualitative analysis aimed at describing the structure and content of the questions generated by the groups. Five different kinds of questions were identified and labelled, encyclopaedic, meaning-oriented, relational, value-oriented and solution-oriented. All scenarios generated questions pertaining to all five categories in all groups, but the emphasis varied. The results are discussed in relation to the design of scenarios, and in relation to students' approaches to learning.

  • 2.
    Abrandt Dahlgren, Madeleine
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Studies in Adult, Popular and Higher Education.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Questioning to learn and learning to question: Structure and function of PBL scenarios in environmental science education.2000In: Second International Conference on Problem-Based Learning in Higher Education,2000, 2000Conference paper (Other academic)
    Abstract [en]

    In problem-based learning, scenarios relating to real life are used as a point of departure for the learning process. Even though the importance of suitable cases or scenarios to bring about a fruitful learning process is emphasised in the literature, few studies focus on how they actually function in the learning process. This study focuses on how the scenarios used in a ten-week introductory course of a new four-year, undergraduate programme in environmental science functioned in terms of the structure and content of the questions they evoked. Data were gathered through diary notes from nine groups of students, comprising 5-8 students per group. The data were subjected to a qualitative analysis aimed at describing the structure and content of the questions generated by the groups. Five different kinds of questions were identified and labelled; A. Encyclopaedic, B. Meaning-oriented, C. Relational, D. Value-oriented and E. Solution-oriented.  All scenarios generated questions pertaining to all five categories in all groups, but the emphasis varied. The results are discussed in relation to the design of scenarios, and in relation to students’ approaches to learning.

  • 3.
    Abrandt Dahlgren, Madeleine
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Studies in Adult, Popular and Higher Education.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Real-life situations as a promotor of the learning process1999In: 5th auDes international conference in environmental sciences,1999, 1999Conference paper (Other academic)
  • 4.
    Abrandt Dahlgren, Madeleine
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Studies in Adult, Popular and Higher Education.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Structure and function of PBL scenarios in environmental science education.1999In: Universitetspedagogisk konferens: CUL-dagen 1999,1999, Linköping: Linköpings universitet , 1999, p. 109-116Conference paper (Other academic)
  • 5.
    Alkan Olsson, Johanna
    et al.
    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. Linköping University, Faculty of Arts and Sciences.
    Critical Load: The politics of chemistryManuscript (preprint) (Other academic)
    Abstract [en]

    Critical Load was introduced as a environmental policy tool in the late 1980s in response to a need for exact and scientifically based measures to abate transboundary air pollution in the Convention onLong-Range Transboundary Air Pollution (CLRTAP). The main objective in this study was to analyse the practical operationalisation of these limits. The study proceeded by analysing policy document treating the Critical Load concept produced by the Swedish Environmental Protection Agency (SEP A) It is showed that the concept is mainly operationalised through three scientific disciplines, chemistry, ecology and toxicology. Chemistry dominates and two things are forwarded as a reason. First, the political over all aim of Critical Load is based on the ideas that nature is robust within limits a perception, which is closely entangled with an idea that it is possible to calculate these limits. This favours chemical explanations, as chemistry is perceived as more calculable than for example ecology. Secondly, the Critical Load concept was initially used in connection to acidification, which primarily has been perceived a chemical problem. As ecological  explanations in the material not are operationalised into precise limitsthe role of ecology is interpreted as a complement to the precise calculations provided by chemistry, taking into consideration the balance and the complexity of nature. Toxicological explanations on the other hand provide precise measurements and are therefore interpreted as an intermediary between ecology and chemistry. Thethree stories are therefore interpreted as versions on the same story,nature as robust within limits and calculable. The ecological and thetoxicological explanations are also interpreted as answers to a changein the perception of environmental problem to more complex and to achanging focus of polluting compounds in the CLRTAP.

  • 6.
    Alkan Olsson, Johanna
    et al.
    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. Linköping University, Faculty of Arts and Sciences.
    The Critical Load graph: A rhetorical tropeManuscript (preprint) (Other academic)
    Abstract [en]

    It is often said that pictures and graphical visualisations have a greatpower to unify and simplify ideas: "a picture says a thousand words" as thesaying goes. The ability of graphs to explore and summarise large sets ofnumbers is also well known (Tufte, 1983: introduction). Although scientistsfrequently have recourse to graphical illustrations when explaining complexproblems, the role of pictures and graphs in forwarding scientific findingshas received relatively little attention in studies of science compared to the attention given to texts. Ronald Giere and Michael Ruse have suggested thatthis lack of interest may be explained by the strong influence of logical empiricism in scientific culture (Giere, 1996; Ruse, 1996). Logical empiricism emerged in the eighteenth century in the transition between an oral-visualculture and a text-based culture, nurturing a suspicion towards pictures andarguing that human thinking relies on words. In this textual culture pictures are reduced to persuasive aids, if considered at all, being thought of as pedagogical tools or simple 'illustrations' used to facilitate the presentation and sharing of scientific findings (Stafford, 1994). Another reason why visual displays in science have been underestimated and neglected compared to scientific texts, may simply be, as suggested by David Lynch, that methods for analysing verbal materials are more advanced than thosefor analysing pictures (Lynch, 1990:151).

    (...)

  • 7.
    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.

  • 8.
    Bengtson, P.
    et al.
    Lund University, Sweden.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    de Boer, W.
    Centre for Terrestrial Ecology, Netherlands.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Possible role of reactive chlorine in microbial antagonism and organic matter chlorination in terrestrial environments2009In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 11, no 6, p. 1330-1339Article in journal (Refereed)
    Abstract [en]

    Several studies have demonstrated that extensive formation of organically bound chlorine occurs both in soil and in decaying plant material. Previous studies suggest that enzymatic formation of reactive chlorine outside cells is a major source. However, the ecological role of microbial-induced extracellular chlorination processes remains unclear. In the present paper, we assess whether or not the literature supports the hypothesis that extracellular chlorination is involved in direct antagonism against competitors for the same resources. Our review shows that it is by no means rare that biotic processes create conditions that render biocidal concentrations of reactive chlorine compounds, which suggest that extracellular production of reactive chlorine may have an important role in antagonistic microbial interactions. To test the validity, we searched the UniprotPK database for microorganisms that are known to produce haloperoxidases. It appeared that many of the identified haloperoxidases from terrestrial environments are originating from organisms that are associated with living plants or decomposing plant material. The results of the in silico screening were supported by various field and laboratory studies on natural chlorination. Hence, the ability to produce reactive chlorine seems to be especially common in environments that are known for antibiotic-mediated competition for resources (interference competition). Yet, the ability to produce haloperoxidases is also recorded, for example, for plant endosymbionts and parasites, and there is little or no empirical evidence that suggests that these organisms are antagonistic.

  • 9.
    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)
  • 10.
    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.

  • 11. do Nascimento, NR
    et al.
    Nicola, SMC
    Rezende, MOO
    Oliveira, TA
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Pollution by hexachlorobenzene and pentachlorophenol in the coastal plain of Sao Paulo state, Brazil2004In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 121, no 03-Apr, p. 221-232Article in journal (Refereed)
    Abstract [en]

    Organochlorine compounds were dumped by chemical industries during the 1970s in many areas of the coastal plain of Sao Paulo state in Brazil. These dumps, located on hillsides and in valleys, in both rural and urban environments, are responsible for soil and water pollution. The objective of this work was to determine how the pollutants have spread in an area occupied by a spodosol-type soil mantle. The study combines soil morphological observations with soil and water analysis of hexachlorobenzene (HCB) and pentachlorophenol (PCP) in soil toposequences. The results indicate that the highest pollutant concentrations are observed near the dump site and that the compounds contamination is increasing. A map integrating topography and chemical concentrations was created to visualize the spatial distribution of HCB levels in the landscape. Physical and chemical analyses were performed to measure HCB and PCP levels in the soil. Soil water appears to act as a vector of HCB, probably through complexation with and dispersal of dissolved organic matter. The persistence of HCB at the studied site is most likely due to the low pH values in combination with a high content of organic matter. HCB was consistently found in higher concentrations than PCP. It is plausible that the cause of this difference is that PCP is degraded more easily under sunlight than HCB and that degradation of PCP under acid conditions leads to the formation of HCB. (C) 2003 Published by Elsevier B.V.

  • 12.
    Hjelm, Olof
    et al.
    Linköping University, Department of Mechanical Engineering, Environmental Technique and Management. Linköping University, The Institute of Technology.
    Johansson, Emma
    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.
    Production of organically bound halogens by the litter-degrading fungus Lepista nuda1999In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 31, no 11, p. 1510-1515Article in journal (Refereed)
    Abstract [en]

    The ability of Lepista nuda to produce organically bound halogens was tested both in a laboratory study of a pure culture and in a field study. It was found that L. nuda caused an increase in the total amount of organically bound halogens in the study of a pure culture, but possibly because of large variance between replicates, no such increase could be detected in the field study. In addition, in both the laboratory and the field studies, low-molecular-weight organohalogens such as chlorinated benzaldehydes were detected in all samples affected by the fungus and the amounts were 0.2–82 μg/g d.w. These low-molecular-weight compounds correspond to approximately 30% of the increase in organohalogens detected in the laboratory study. It is suggested that the low-molecular-weight organohalogens detected, most likely are produced de novo by L. nuda and that production of such compounds followed by an incorporation into high-molecular-weight compounds is an explanation for the increase in amounts in the laboratory study.

  • 13. Johansson, E.
    et al.
    Krantz-Rülcher, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Zhang, B.X.
    Institute of Soil Science, Academica Sinica, Nanjing, China.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Chlorination and biodegradation of lignin2000In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 32, no 7, p. 1029-1032Article in journal (Refereed)
    Abstract [en]

    Recent research has shown that large amounts of high-molecular weight organic chlorine of unknown origin are present in the terrestrial environment. There are indications that an underlying process may be microorganisms which produce reactive chlorine that chemically degrades organic matter and facilitates degradation of recalcitrant organic matter on one hand, and on the other hand causes a formation of organic chlorine. Our aim was to test one part of this hypothesis by investigating whether reactive chlorine facilitates microbial degradation of lignin. Different concentrations of chlorine dioxide were added to the autoclaved lignin suspension. Mycelium of the white-rot fungus P. chrysosporium was used to inoculate flasks with the lignin solutions. The evolution of CO2 was followed during 8 d of continuous measurement. At the end of the experiment the solutions were analyzed for organic chlorine. The amount of CO2 evolved was variable, but the results were repeatedable, addition of chlorine dioxide to the lignin solutions caused an increase in the mineralization by P. chrysosporium that increased with increasing additions of chlorine dioxide. This suggests that exposure of lignin to reactive chlorine enhance its biodegradability. The most likely cause of the observed effect is that the addition of chlorine dioxide initiated a fragmentation and oxidation of the lignin, thus rendering a more easily degraded substrate. However, the results may also be interpreted as if an additional cause to the observed effect is that the chlorination in itself somehow enhanced degradation. The amount of organically-bound chlorine decreased during the incubation, and the decrease was more pronounced with the chlorination of lignin, whereas no change at all was observable in the control batches. This makes it tempting to suggest that P. chrysosporium rather than having an enzyme system just capable of handling the chlorinated compounds, actually has a system that preferentially degrades such compounds. (C) 2000 Elsevier Science Ltd.

  • 14.
    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.

  • 15.
    Johansson, Emma
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sandén, Per
    Linköping University, Department of Thematic 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.
    Organic chlorine in deciduous and coniferous forest soils in southern Sweden2003In: Soil science, ISSN 0038-075X, E-ISSN 1538-9243, Vol. 168, no 5, p. 347-355Article in journal (Refereed)
    Abstract [en]

    The concentration of organic chlorine (Clorg) was determined in soil samples collected in the O-horizon in forest soils in southern Sweden to describe differences among stand types and elucidate the influence of chloride (Clinorg), pH, and organic carbon. The samples were collected within the Swedish National Survey of Forest Soils and Vegetation, with moraine as the dominating soil type and with granite and gneiss as bedrock. The concentration of organic chlorine (Clorg) found in the deciduous forest soils was significantly lower than that in the coniferous forest soils. The Clorg increased with Clinorg, organic carbon content, and decreasing pH but was most strongly correlated to Clinorg. Crosswise comparisons among the variables showed that the influence of Clinorg overrode the influence of pH and organic carbon. We concluded that the major driving force in the formation of Clorg in soils is deposition of Clinorg and that the difference among deciduous and coniferous stands is due primarily to a higher input of Clinorg in the canopy of coniferous trees as a result of a larger wet and dry deposition in coniferous compared with deciduous forests. The concentration of Clorg decreased significantly from June to August. This follows the pattern of chloride deposition in the region and gives further evidence that Clinorg is a driving force in the formation of Clorg in soil. The results of the present study gives further evidence that the turnover of Clorg is closely related to the turnover of Clinorg and that it is necessary to include Clorg in the assessment of the biogeochemical cycling of chlorine in the environment.

  • 16.
    Johansson, Emma
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sandén, Per
    Linköping University, Department of Thematic 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.
    Spatial patterns of organic chlorine and chloride in Swedish forest soil2003In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 52, no 2, p. 391-397Article in journal (Refereed)
    Abstract [en]

    The concentration of organic carbon, organic chlorine and chloride was determined in Swedish forest soil in the southern part of Sweden and the spatial distribution of the variables were studied. The concentration of organically bound chlorine was positively correlated to the organic carbon content, which is in line with previous studies. However, the spatial distribution patterns strongly indicate that some other variable adds structure to the spatial distribution of organic chlorine. The distribution patterns for chloride strongly resembled the distribution of organic chlorine. The spatial distribution of chloride in soil depends on the deposition pattern which in turn depends on prevailing wind-direction, amount of precipitation and the distance from the sea. This suggests that the occurrence of organic chlorine in soil is influenced by the deposition of chloride of some variable that co-varies with chloride. Two clearly confined strata were found in the area: the concentrations of organic chlorine and chloride in the western area were significantly higher than in the eastern area. No such difference among the two areas was seen regarding the carbon content.

  • 17.
    Johansson, Emma
    et al.
    Linköping University, The Institute of Technology. Linköping University, Faculty of Arts and Sciences.
    Xin, ZB
    Hu, ZY
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Organic chlorine and chloride in submerged paddy soil: a case study in Anhui province, southeast China2004In: Soil use and management, ISSN 0266-0032, E-ISSN 1475-2743, Vol. 20, no 2, p. 144-149Article in journal (Refereed)
    Abstract [en]

    Efforts to understand the fate of organochlorine compounds in arable soil have concentrated on anthropogenic compounds, in spite of the fact that organochlorine compounds are both produced and mineralized in soil through natural processes. In order to understand the fate of chlorinated pesticides, it is necessary to take account of the natural chlorine cycle. The present study is a first attempt to illuminate the relationship between the natural chlorine cycle and agricultural practices. The concentration and storage of organic chlorine (Cl-org) and chloride (Cl-inorg) were determined in topsoil of a paddy field compared to an adjacent afforested hill at a sampling site in the Meicun area, Anhui Province, China. The concentration of Cl-org, as well as the chlorine-to-carbon ratio, was significantly lower in the paddy field samples than in the forest soil samples. A weak relationship between the concentration of Cl-org and the organic carbon content was observed in the paddy field, in contrast to the observations made in the adjacent forest soil as well as those made in previous studies, which have suggested a positive correlation between organic carbon content and Cl-org. The similarity between our results at the forest site and the previous studies, which have been carried out in temperate regions, suggests that it is the land use rather than the climate that makes the current paddy soil results different. Our results suggest that the contribution of Cl-org to the paddy soil from above-ground litter and from production within the soil are small or negligible compared with the contribution from pesticide application and wet and dry deposition.

  • 18.
    Johansson, Emma
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Zhang, Björn Xin
    Institute of Soil Science, Academica Sinica, Nanjing, P.R. China.
    Hu, Zhengyi
    Institute of Soil Science, Academica Sinica, Nanjing, P.R. China.
    Sandén, Per
    Linköping University, The Tema Institute. 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.
    Spatial Patterns of Organic Chlorine and Chloride in Farmland and Forest Soil in the Meicun Area, South East ChinaManuscript (preprint) (Other academic)
    Abstract [en]

    The concentration and storage of organic chlorine and chloride were determined in topsoil in a coniferous forest soil and a paddy soil at a sampling site in the Meicun area, Anhui Province, P.R. China. Also, the spatial distribution of the two forms of chlorine was determined and linear interpolation was used to construct contour maps of the concentrations. Soil samples were collected at 55 of the nodes in a grid with approximately 120 m between the nodes. In all, 27 samples from the forest and 28 from the paddy soil were collected and analyzed with respect to chloride, organic chlorine, organic carbon, pH, total nitrogen,ammonium and nitrate.

    The concentration of organic chlorine was at both sites significantly lower than that of chloride. Furthermore, the concentration of organic chlorine was significantly lower in the paddy as compared to the forest soil whereas the concentration of chloride did not differ significantly.

    The analysis of spatial variability suggested that no spatial correlation between the nearest sampling points and those further away were at hand. The contour maps indicated that the distribution pattern of organic chlorine in the forest soil was similar to the distribution of organic carbon, the highest and lowest concentrations of each occurring at about the same locations in the grid. The distribution of chloride showed a different pattern where the highest concentrations coincided with the most elevated parts of the hill. No clear patterns were observed for the three variables in the paddy field.

  • 19.
    Johansson, Madelaine
    et al.
    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.
    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.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences.
    Vem äger frågan?: Förutsättningar för kommunikation i svenskt miljömålsarbet2005Report (Other academic)
    Abstract [sv]

    Ständiga förändringar i samhället ökar kraven på flexibilitet och nya strategier för att hantera miljöproblematiken och arbetet med att nå en hållbar utveckling.Det kan uppstå problem när samhället ska anpassa sig efter nya strukturer och nyuppkomna behov, exempelvis när det gäller miljöhot. De nya krav som kopplas till hållbar utveckling och dess ekologiska dimensionreser krav på förändrad politisk styrning. I Sverige har det beslutats attmiljöfrågor ska vara övergripande för alla politiska områden. Formulering avplaner och program för ekologisk hållbar utveckling införs därför i olika typerav styrningssystem som bygger på olika sorts logik vilket kan leda till intressekonflikter.Det övergripande målet för svensk miljöpolitik är att till nästa generation lämnaöver ett samhälle där de stora miljöproblemen är lösta och där mänskligpåverkan på miljön är långsiktigt hållbar. År 1999 fastställdes en ny struktur ihållbarhetsarbetet genom framtagandet av 15 nationella miljökvalitetsmål och inovember 2001 antog riksdagen regeringens förslag om delmål och riktlinjer förhur dessa miljömål ska uppnås. Tanken är att miljökvalitetsmålen ska gevägledning för allt miljöarbete inom såväl olika samhällssektorer som på olikanivåer i miljömålsadministrationen. Regionala mål och sektorsmål ska utvecklasmed utgångspunkt i de mål som beslutats av riksdagen. Syftet med studien som ligger till grund för denna rapport var att identifierahinder för kommunikation i miljömålsarbetet och därigenom underlätta överbryggandet av kommunikationsbarriärer i framtida miljöarbete. Vi harstuderat hur aktörer på olika nivåer inom miljömålsadministrationen ser på målstyrning och arbetet med de svenska miljökvalitetsmålen med syfte att synliggöra hur kommunikationen kring miljömålen uppfattas.Vi har särskilt fokuserat på:

    • kommunikation mellan administrativa nivåer, i allmänhet och rörandeuppföljningsarbetet i synnerhet
    • hur målstyrning fungerar i praktiken• vad som kan och bör mätas i uppföljningen av miljömålsarbetet
    • möjligheter till feedback mellan olika aktörer och administrativa nivåer.
  • 20.
    Karlsson, Susanne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    UV-light induced mineralization of organic matter bound chlorine in Lake BjΣn, Sweden - A laboratory study2003In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 52, no 2, p. 463-469Article in journal (Refereed)
    Abstract [en]

    Surface water and aqueous solutions of isolated organic matter from a humic rich lake in southern Sweden were exposed to artificial UV radiation to investigate the UV light induced influence on organic matter bound chlorine in natural systems. It was found that the photodegradation of organic matter bound chlorine was more pronounced than the photodegradation of organic carbon. After 120 h of irradiation of the isolated organic matter, only 35% of the initial organochlorine was still in the solution compared to about 70% of the dissolved organic carbon (DOC). A similar result was obtained for unfractionated surface water. Furthermore, our results indicate that the loss of organic chlorine was mainly due to a mineralization of organic chlorine into chloride ions. The total decrease of organic chlorine after 120 h was 32 ╡g Clorg l-1, of which the major part disappeared in the initial irradiation phase. A similar increase was observed in the chloride concentration (34 ╡g Cl- l-1).

  • 21.
    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.

  • 22.
    Lovbrand, E.
    et al.
    Department of Biology and Environmental Science, Kalmar University, Kalmar, Sweden.
    Öberg, Gunilla
    Linköping University, Department of Thematic Studies, Environmental Science. Linköping University, Faculty of Arts and Sciences.
    Comment on "How science makes environmental controversies worse" by Daniel Sarewitz, Environmental Science and Policy, 7, 385-403 and "When Scientists politicise science: Making sense of the controversy over The Skeptical Environmentalist" by Roger A. Pielke Jr., Environmental Science and Policy, 7, 405-4172005In: Environmental Science and Policy, ISSN 1462-9011, E-ISSN 1873-6416, Vol. 8, no 2, p. 195-197Article in journal (Other academic)
    Abstract [en]

    [No abstract available]

  • 23. Rodstedth, M
    et al.
    Ståhlberg, Carina
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Chloride imbalances in soil lysimeters2003In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 52, no 2, p. 381-389Article in journal (Refereed)
    Abstract [en]

    The assumption that soil neither acts as a source or a sink of chloride is evaluated by incubating soil cores in lysimeters in a climate chamber under controlled conditions. Some of the lysimeters acted as a sink while others acted as a source of chloride. Considerable amounts of organic chlorine were lost by leaching. The loss by leaching of organic chlorine could only explain part of the discrepancy in the lysimeters where the soil acted as a sink and it could certainly not explain the cases where the soil acted as a source. The storage of organic chlorine was four times larger than the storage of chloride and comparably small changes in the organic chlorine storage will thus have a considerable influence on the chloride budget. However, the soil was too heterogeneous to determine whether a change in the storage had taken place or not. It is concluded that the observed chloride surplus and also, at least to some extent, the observed chloride deficit, most likely was caused by net-changes in the storage of organic chlorine in soil. An inverse correlation was found between the initial chloride content of the soil and the imbalance in the chloride budget. Dry deposition of chloride is generally assumed to equal the run-off minus the wet deposition. Extrapolation to the field situation suggests that the output of organic chlorine by soil leachate is at risk to cause an underestimation of the dry deposition by about 25%. (C) 2003 Elsevier Science Ltd. All rights reserved.

  • 24.
    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.

  • 25.
    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)
  • 26.
    Wibeck, Victoria
    et al.
    Linköping University, Department of Thematic Studies, Centre for Climate Science and Policy Research. Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Abrandt Dahlgren, Madeleine
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning, Studies in Adult, Popular and Higher Education.
    Öberg, Gunilla
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Learning in focus groups: An analytical dimension for enhancing focus group research2007In: Qualitative Research, ISSN 1468-7941, E-ISSN 1741-3109, Vol. 7, no 2, p. 249-267Article in journal (Refereed)
    Abstract [en]

    The focus group is a research methodology in which a small group of participants gathers to discuss a specified issue under the guidance of a moderator. The discussions are tape-recorded, transcribed and analysed. Notably, the interaction between focus group participants has seldom been evaluated, analysed or discussed in empirical research. We argue that considering the focus group in light of current research into interaction in problem-based learning (PBL) tutorial groups would facilitate the deliberate exploitation of group processes in designing focus groups, staging data collection and analysing and interpreting data. When the analytical focus shifts from mere content analysis to an analysis of what the participants themselves are trying to learn, one can explore not only what the participants are talking about, but also how they are trying to understand and conceptualise the issue under discussion. © 2007 Sage Publications.

  • 27.
    Wibeck, Victoria
    et al.
    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.
    Johansson, Madelaine
    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.
    Larsson, Anna
    Länsstyrelsen, Södermanland.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Communicative aspects of environmental management by objectives: Examples from the Swedish context2006In: Environmental Management, ISSN 0364-152X, E-ISSN 1432-1009, Vol. 37, no 4, p. 461-469Article in journal (Refereed)
    Abstract [en]

    Management by objectives (MBO) is a technique for integrating ecological concerns into national political and administrative structures. Politicians determine environmental objectives and interim targets to be implemented and assessed by civil servants in national, regional, and local contexts. Well-developed organizational communication is a prerequisite for MBO. However, communication-related obstacles can arise when using MBO in public environmental management. We examine communicative aspects of environmental MBO, looking specifically at the implementation, administration, and assessment of Swedish environmental quality objectives. Our argument is illustrated by quotations from individual and focus group interviews. We conclude that communicative problems may arise, because different actors interpret messages from different perspectives, depending on their agendas, prior knowledge and experience, and positions in the administrative system. It is crucial to recognize the dialogical aspects of communication, by involving the receiver of a message in a process of response. In addition, the different timeframes underlying different arguments could contribute to misunderstandings between actors involved in handling environmental issues. In assessing the achievement of environmental objectives, indicators are used as communicative tools. It is important to investigate whether and how these indicators contribute to the de- and recontextualization of environmental objectives. © 2006 Springer Science+Business Media, Inc.

  • 28.
    Öberg (fd Asplund), Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    On the origin of organohalogens found in the environment1992Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The natural production of halogenated organic compounds in the environment is often assumed to be negligible compared to the anthropogenic production of such compounds. A change in this general view is advocated in the present thesis.

    Amounts of halogenated organic compounds were measured by detennination of AOX (adsorbable organic halogen) or TOX (total organic halogen), and it was found that these compounds are more widespread than previously assumed. A national organohalogen budget was established by calculating chlorine-to-carbon ratios for different types of samples and then combining these values with studies of organic carbon pools in Sweden. The obtained budget showed that the major fraction of organohalogens is stored in soil and freshwater sediments (approx. 5000 x J03 and 2000 x J03 tonnes, respectively).

    It was also found that soil extracts obtained by using an enzyme extraction procedure were able to catalyze chlorination of organic compounds. The reaction did not proceed in the absence of hydrogen peroxide or after the soil extract had been heated; furthermore the catalyst had a molecular weight that was greater than 10,000, exhibited decreasing activity with time and rising temperature, and was inhibited by phloroglucinol, resorcinol, orcinol and ethanol. In all these respects the soil derived catalyst resembled a commercial chlorperoxidase. Based on these findings, it was concluded that a chloroperoxidase-like catalyst is present in soil. In this context it is also noteworthy that a net production of organohalogens ~as found in soil stored under controlled conditions.

    The soil-extract-catalyzed chlorination, the detected net production in soil, and the background concentration of organohalogens in surface water were all found to increase with decreasing pH. This implies that the natural production of halogenated organic compounds may increase with acidification of soil and surface water.

  • 29.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Chloride and Organic Chlorine in Soil1998In: Acta Hydrochimica et Hydrobiologica, ISSN 0323-4320, E-ISSN 1521-401X, Vol. 26, no 3, p. 137-144Article in journal (Refereed)
  • 30.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    The biogeochemistry of chlorine in soil2003In: The handbook of environmental chemistry: Vol. 3. P. P, Anthropogenic compounds. Natural production of organohalogen compounds / [ed] Gordon W. Gribble, Springer Verlag , 2003, p. 43-62Chapter in book (Other academic)
    Abstract [en]

    Summarizes the knowledge on naturally occurring organohalogens, of which more than 3700 are documented. This book features chapters that cover various aspects of this field, including the structural diversity and sources of organohalogens, the mechanisms for their formation and biodegradation, the clinical use of dichloroacetate, and more

  • 31.
    Öberg, Gunilla
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    The natural chlorine cycle - fitting the scattered pieces2002In: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 58, no 5, p. 565-581Article, review/survey (Refereed)
    Abstract [en]

    Chlorine is one of the most abundant elements on the surface of the earth. Until recently, it was widely believed that all chlorinated organic compounds were xenobiotic, that chlorine does not participate in biological processes and that it is present in the environment only as chloride. However, over the years, research has revealed that chlorine takes part in a complex biogeochemical cycle, that it is one of the major elements of soil organic matter and that the amount of naturally formed organic chlorine present in the environment can be counted in tons per km(2). Interestingly enough, some of the pieces of the chlorine puzzle have actually been known for decades, but the information has been scattered among a number of different disciplines with little or no exchange of information. The lack of communication appears to be due to the fact that the points of departure in the various fields have not corresponded, a number of paradoxes are actually revealed when the known pieces of the chlorine puzzle are fit together. It appears as if a number of generally agreed statements or tacit understandings have guided perceptions, and that these have obstructed the understanding of the chlorine-cycle as a whole. The present review enlightens four paradoxes that spring up when some persistent tacit understandings are viewed in the light of recent work as well as earlier findings in other areas. The paradoxes illuminated in this paper are that it is generally agreed that: (1) chlorinated organic compounds are xenobiotic even though more than 1,000 naturally produced chlorinated compounds have been identified, (2) only a few, rather specialised, organisms are able to convert chloride to organic chlorine even though it appears as if the ability among organisms to transform chloride to organic chlorine is more the rule than the exception,, (3) all chlorinated organic compounds are persistent and toxic even though the vast majority of naturally produced organic chlorine is neither persistent nor toxic, (4) chlorine is mainly found in its ionic form in the environment even though organic chlorine is as abundant or even more abundant than chloride in soil. Furthermore, the contours of the terrestrial chlorine cycle are outlined and put in a concrete form by constructing a rough chlorine budget over a small forested catchment. Finally, possible ecological roles of the turnover of chlorine are discussed.

  • 32.
    Öberg, Gunilla
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Grøn, C.
    Sources of Organic Halogens in Spruce Forest Soil1998In: Environmental Science and Technology, ISSN 1086-931X, E-ISSN 1520-6912, Vol. 32, no 11, p. 1573-1579Article in journal (Refereed)
  • 33.
    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)
  • 34.
    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.

  • 35.
    Öberg, Gunilla
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Lövbrand, Eva
    Department of Biology and Environmental Science Kalmar University.
    Towards reflexive scientization of environmental policy2005In: Environmental Science and Policy, ISSN 1462-9011, E-ISSN 1873-6416, Vol. 8, no 2, p. 195-197Article in journal (Refereed)
  • 36.
    Öberg, Gunilla
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Niedan, Volker
    Pavasars, Ivars
    Chloroperoxidase-mediated chlorination of aromatic groups in fulvic acid2000In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 41, no 5, p. 779-785Article in journal (Refereed)
    Abstract [en]

    The aim of the present study is to investigate whether exo-enzymatically mediated chlorination of fulvic acid (FA) results in the formation of chlorinated groups within the macromolecules which correspond to those which were previously detected in soil and surface water samples. The chlorination was carried out by exposing FA to a commercial chloroperoxidase (CPO) in the presence of chloride and hydrogen-peroxide. The exposed FA was then chemically degraded using an oxidative technique and finally analysed for four different aromatic groups and their chlorinated analogues. The particular aromatic groups included were the methyl esters of 4-ethoxybenzoic acid, 3-methoxy-4-ethoxybenzoic acid, 3,4-diethoxybenzoic acid, and 3,5- dimethoxy-4-ethoxybenzoic acid, along with their mono-and dichlorinated analogues. Prior to the chemical degradation procedure, the FA was analysed for AOX (adsorbable organic halogens) and chlorinated acetic acids. The original FA contained 1.4 mg Cl(org) g-1 and detectable amounts of two chlorinated aromatic groups. After exposure to the enzyme, the concentration of AOX increased to 44.3 mg Cl(org) g-1 and detectable amounts of four chlorinated aromatic groups as well as di- and trichloroacetic acid were found. (C) 2000 Elsevier Science Ltd.

  • 37.
    Öberg, Gunilla
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Environmental Science.
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Retention of chloride in soil and cycling of organic matter-bound chlorine2005In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 19, no 11, p. 2123-2136Article in journal (Refereed)
    Abstract [en]

    Chloride (Cl-inorg) is generally considered to be a hydrologically and chemically inert substance. Past research suggests that Cl-inorg participates in a complex biogeochemical cycle involving the formation of organically bound chlorine (Cl-org). The present study examines whether Cl-org cycling is sufficiently extensive as to influence the geochemical cycling Of Cl-inorg- Undisturbed soil cores were collected in a coniferous forest soil in SE Sweden. The cores were stored in climate chambers for three months, irrigated with artificial rain, and the leachate was collected and analysed. The water balance of the lysimeters could be well described, and we found that 20-50% of the chlorine leached from the lysimeters was organically bound and that the amounts lost did not decrease with time. This strongly suggests that a substantial amount of Cl-inorg forms in topsoil, and that subsequent leaching to deeper layers causes a considerable withdrawal of Cl-inorg. The concentration of both organic carbon and Cl-inorg in the leachate was considerably higher than concentrations observed in the runoff in the actual catchment, suggesting that organic matter precipitates or is mineralized on its way through the soil. Copyright (c) 2005 John Wiley & Sons, Ltd.

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