| 1. |
- Ebenå, Gustav
(författare)
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Sulfidic mine waste microorganisms in an ecological context
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The focus of this thesis are the microorganisms found in sulfidic minewaste and their ecology. The microorganisms are investigated from the point of view of being an important, if not the most important, factor in the production of acid rock drainage (ARD). The thesis is a summary of several studies. One study was trying to find a good way of separating the organisms from its abiotic counterpart by different means of sterilization. The effectiveness of the methods as well as their effect on the minerals was investigated.The carbon metabolism in a soil covered impoundment was investigated with the aim of unraveling the composition of the microbial ecosystem. The results agreed with the two case studies, from soil and water covered impoundments that indicate a very uneven distribution of the bacteria. The presence of microbial hotspots where autotrophic bacteria acts as primary producers and creates conditions for a wide range of bacteria and a relatively high activity seems a reasonable conclusion from these studies.In yet another study the effect of low temperatures was investigated.The conclusion from this study was that there was considerable activity even at temperatures 4°C or perhaps even lower.In summary the picture of a highly active and dynamic ecosystem is emerging. An ecosystem with a very uneven distribution of organisms, which in part could explain difficulties in transferring laboratory results to the field situation.
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| 2. |
- Pérez Rodríguez, Nathalie, et al.
(författare)
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The role of bacterial consortium and organic amendment in Cu and Fe isotope fractionation in plants on a polluted mine site
- 2014
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 21:11, s. 6836-6844
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Tidskriftsartikel (refereegranskat)abstract
- Copper and iron isotope fractionation by plant uptake and translocation is a matter of current research. As a way to apply the use of Cu and Fe stable isotopes in the phytoremediation of contaminated sites, the effects of organic amendment and microbial addition in a mine spoiled soil seeded with Helianthus annuus in pot experiments and field trials were studied. Results show that the addition of a microbial consortium of ten bacterial strains has an influence on Cu and Fe isotope fractionation by the uptake and translocation in pot experiments, with an increase in average of 0.99‰ for the δ65Cu values from soil to roots. In the field trial, the amendment with the addition of bacteria and mycorrhiza as single and double inoculation enriches the leaves in 65Cu compared to the soil. As a result of the same trial, the δ56Fe values in the leaves are lower than those from the bulk soil, although some differences are seen according to the amendment used. Siderophores, possibly released by the bacterial consortium, can be responsible for this change in the Cu and Fe fractionation. The overall isotopic fractionation trend for Cu and Fe does not vary for pots and field experiments with or without bacteria. However variations in specific metabolic pathways related to metal-organic complexation and weathering can modify particular isotopic signatures.
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| 3. |
- Schindler, Frank, et al.
(författare)
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Seasonal change of microbial activity inmicrobially aided bioremediation
- 2017
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Ingår i: Journal of Geochemical Exploration. - : Elsevier. - 0375-6742 .- 1879-1689. ; 174, s. 4-9
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Tidskriftsartikel (refereegranskat)abstract
- Microbial community patterns and their potential substrate utilization were examined to test for sustainability in metal polluted soil. The acid mine drainage (AMD) influenced test field was characterized for total soil respiration and the functional diversity of the soil bacterial communities using BIOLOG EcoPlate assays. Inoculation with the mycorrhizal fungus Rhizophagus irregularis and two streptomycetes led to an altered metabolic diversity and soil vitality, with cell numbers increased by one to three orders of magnitude. The change in metabolic activity was stable even after one winter with severe frost periods. The inoculation thus resulted in enhanced microbial activities. This vitalization resulted in enhanced formation of soil organic matter which, in turn, can sustain higher microbial cell numbers. We therefore conclude that inoculation with indigenous bacteria and a versatile mycorrhizal fungus results in improved vitality suitable for plant growth at heavy metal polluted soils. This holds a huge potential for the remediation of the legacies of mining activities and allows for land-use strategies on metal contaminated sites the world-over.
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| 4. |
- Schütze, Eileen, et al.
(författare)
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Siderophore production by streptomycetes-stability and alteration of ferrihydroxamates in heavy metal-contaminated soil
- 2015
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 22:24, s. 19376-19383
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Tidskriftsartikel (refereegranskat)abstract
- Heavy metal-contaminated soil derived from a former uranium mining site in Ronneburg, Germany, was used for sterile mesocosms inoculated with the extremely metal-resistant Streptomyces mirabilis P16B-1 or the sensitive control strain Streptomyces lividans TK24. The production and fate of bacterial hydroxamate siderophores in soil was analyzed, and the presence of ferrioxamines E, B, D, and G was shown. While total ferrioxamine concentrations decreased in water-treated controls after 30 days of incubation, the sustained production by the bacteria was seen. For the individual molecules, alteration between neutral and cationic forms and linearization of hydroxamates was observed for the first time. Mesocosms inoculated with biomass of either strain showed changes of siderophore contents compared with the non-treated control indicating for auto-alteration and consumption, respectively, depending on the vital bacteria present. Heat stability and structural consistency of siderophores obtained from sterile culture filtrate were shown. In addition, low recovery (32 %) from soil was shown, indicating adsorption to soil particles or soil organic matter. Fate and behavior of hydroxamate siderophores in metal-contaminated soils may affect soil properties as well as conditions for its inhabiting (micro)organisms.
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