Search for dissertations about: "geokemi"

Showing result 11 - 15 of 279 swedish dissertations containing the word geokemi.

  2. 11. Export and sources of organic carbon in the Lena River basin, Northeastern Siberia

    Author : Liselott Kutscher; Carl-Magnus Mörth; Per Andersson; Don Porcelli; Peter Raymond; Sebastian Sobek; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; organic carbon; DOC; POC; organic matter; NOM; DOM; POM; Lena River; organsikt kol; DOC; POC; organiskt material; NOM; DOM; POM; Lenafloden; geokemi; Geochemistry;

    Abstract : Permafrost areas are considered to be one of the largest terrestrial storages of carbon. In a warming climate these areas are expected to experience changes in carbon transport to rivers and the oceans due to permafrost thawing, which could enhance erosion, change water flow pathways and increase greenhouse gas emissions. READ MORE

  4. 12. Microbially mediated formation of birnessite-type manganese oxides and subsequent incorporation of rare earth elements, Ytterby mine, Sweden

    Author : Susanne Sjöberg; Christophe Dupraz; Rienk Smittenberg; Volker Brüchert; Helena Filipsson; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; microbial diversity; manganese oxides; birnessite; rare earth elements; subterranean; Ytterby mine; geokemi; Geochemistry;

    Abstract : Microbes exert extensive control on redox element cycles. They participate directly orindirectly in the concentration and fractionation of elements by influencing the partitioningbetween soluble and insoluble species. READ MORE

  5. 13. Isotope-based reconstruction of the biogeochemical Si cycle : Implications for climate change and human perturbation

    Author : Xiaole Sun; Carl-Magnus Mörth; Christoph Humborg; Per Andersson; Brian Fry; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; diatoms; biogenic silica BSi ; dissolved Si DSi ; Si isotope fractionation; the Baltic Sea; geokemi; Geochemistry;

    Abstract : The global silicon (Si) cycle is of fundamental importance for the global carbon cycle. Diatom growth in the oceans is a major sequestration pathway for carbon on a global scale (often referred to as the biological pump). READ MORE

  6. 14. Late-orogenic, ductile shear zones and protolith ages in the Svecofennian domain, central Sweden

    Author : Karin Högdahl; Carl Ehlers; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mineralogy; Petrology and Geochemistry; mineralogi; petrologi och geokemi;

    Abstract : The timing of deformation along ductile shear zones in the Svecofennian Domain in central Sweden has generally been constrained by their relationship to magmatic and metamorphic events of known age. A better resolution for the timing of the deformation can be obtained by direct, radiometric dating of minerals which are constituents of the shear fabric. READ MORE

  7. 15. Hydrothermal alteration of organic matter at spreading centers

    Author : Eva Andersson; Bernd R.T. Simoneit; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Biogeochemistry; biogeokemi;

    Abstract : Alteration of organic matter, mainly amino acids, at sub-seafloor hydrothermal conditions has been investigated by performing laboratory experiments and by studying deep-sea sediments from hydrothermally active areas on the northern Juan de Fuca Ridge, northeast Pacific Ocean.Quaternary sediments from Middle Valley and the eastern flank of the Juan de Fuca Ridge recovered during the Ocean Drilling Program Legs 139 and 168 have been analyzed for total hydrolyzable amino acid concentrations, individual amino acid abundances and stereochemistry in order to evaluate the effects of hydrothermal stress on the decomposition of sedimentary amino acids. READ MORE