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- Börjesson, Gunnar, et al.
(author)
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Microbial oxidation of CH4 at high partial pressures in an organic landfill cover soil under different moisture regimes
- 1998
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In: FEMS Microbiology Ecology. - 0168-6496. ; 26:3, s. 207-217
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Journal article (peer-reviewed)abstract
- The uptake and utilization of CH4 at high concentrations (5-18% vol.) and different soil moistures were followed for samples from a landfill cover soil with a high organic matter content. Measurements of the utilization of CH4 and O2, and production of CO2 indicated that the activity of methanotrophic organisms accounted for most of the O2 respiration. At water saturation, CH4 oxidation rates decreased with time, probably because NH4/+ accumulated. Denitrification rates, estimated based on both N2 and N2O production, were positively related to soil moisture and only slightly influenced by the extent of CH4 oxidation. Total phospholipid fatty acid concentrations increased, and concentrations of phospholipid fatty acids, typical for obligate methanotrophic bacteria (e.g. 16:1ω8 and 18:1ω8), increased in the CH4-amended samples, indicating growth of both type I and type II methanotrophs.
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| 2. |
- Eriksson, Åsa, 1964-
(author)
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Recruitment and distribution patterns of plants in Swedish semi-natural grasslands
- 1999
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Doctoral thesis (other academic/artistic)abstract
- Semi-natural pastures with different histories of management are nowadays the main remnants of the traditional agrarian landscape in southern Sweden. The aims of this thesis were to investigate the importance of features of the present-day landscape and its management history for species distribution and abundance patterns in Swedish semi-natural pastures, with a particular focus on factors affecting recruitment processes. Seedling recruitment in these semi-natural pastures was enhanced by disturbances, with the largest advantage for small-seeded species. The majority of species in semi-natural pastures have small seeds that germinate in the autumn. Seedlings seem to recruit mainly from the local species-pool, with 83 % of the recruited species found in the vegetation, whereas 44 % of the recruited species were found in the seed bank. Plant species diversity and distribution patterns are influenced by management history. In the study of distribution patterns of Thymus serpyllum I found that T. serpyllum populations were associated with Iron Age remnants, indicating that T. serpyllum is dependent on human activities, both for dispersal and for the maintenance of established populations. The highest species diversity was found in pastures with a long continuous management regime, whereas no significant species-area relationship could be detected in the present-day landscape. The highest arbuscular mycorrhizal colonization was also found in pastures with a long continuous management regime. The explanation for this patterns is probably that long continuous management is associated with an increasing likelihood of successful dispersal of plant species as well as of fungal species. Thus, historical distribution of pasture areas and their management history may be more important than the present-day distribution. The effects of the dramatic changes of the cultural landscape during this century, with fragmentation of the landscape and changing management, will work on other time scales. The fact that most species in semi-natural pastures are long-lived perennial species, implies that changes in species composition will be slow. Plantago media was found to have an overall negative population growth rate and a restricted dispersal ability, and this may be viewed as a first step towards visible changes. Dispersal limitation seems to be important in the present-day landscape, with T. serpyllum and P. media as examples of both local and regional dispersal limitation. The lack of area-relationship may also be an effect of "self-similarity" of grasslands. Indeed, I found that the majority of species (61%) in Swedish semi-natural pastures were recorded at the smallest spatial scale (0.01m2), and that the area sampled at this scale comprised only 1.25 % of the area examined. This indicates a small-scale structuring of diversity in these pastures.
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| 3. |
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| 4. |
- Jönsson, Åsa, 1965, et al.
(author)
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Life cycle assessment of flooring materials: Case study
- 1997
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In: Building and Environment. - 0360-1323. ; 32:3, s. 245-255
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Journal article (peer-reviewed)abstract
- The environmental impact of the three flooring materials linoleum, vinyl flooring and solid wood flooring during their life cycles was assessed and compared through life cycle assessment (LCA). The scenarios used describe a Swedish situation. Only impacts on the natural environment were studied The quantitative results of the inventory analysis were evaluated by using three different assessment methods. According to the results, solid wood flooring proved to be clearly the most environmentally sound flooring. Linoleum was ranked as more environmentally sound than vinyl flooring, although this was less evident in comparison with ranking the solid wood flooring.
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