Sökning: "organic geochemistry"

Visar resultat 11 - 15 av 92 avhandlingar innehållade orden organic geochemistry.

  1. 11. Hydrothermal alteration of organic matter at spreading centers

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

    Sammanfattning : 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. LÄS MER

  3. 12. Fate of organic carbon in a tropical mangrove ecosystem

    Författare :John Machiwa; Michael Risk; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biogeochemistry; biogeokemi;

    Sammanfattning : The aim of this thesis was to study the budget and fluxes of organic carbon in a tropical mangrove forest. Maruhubi forest is located in the Island of Zanzibar, East Africa. Aspects of structure and functions of the ecosystem are investigated. LÄS MER

  4. 13. Geochemistry of suspended material and sediments in boreal lakes

    Författare :Elsa Peinerud; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

    Sammanfattning : The geochemistry of suspended material and sediment has been studied in four boreal lakes: Lakes Kutsasjärvi, Sakajärvi, and Ala Lombolo in northern Sweden and Lake Imandra on the Kola Peninsula, Russia. Suspended material and filtered water have been sampled in time series and depth profiles. LÄS MER

  5. 14. Iron isotopes in aquatic systems

    Författare :Sarah Conrad; Johan Ingri; Michael Bau; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geochemistry; Tillämpad geokemi;

    Sammanfattning : The cycling of iron (Fe) is a key component for understanding water quality and biogeochemical processes. It serves as mediator during biotic and abiotic processes, as electron acceptor during the degradation of organic matter, as surface for trace element and organic matter adsorption, and is necessary for primary production processes. LÄS MER

  7. 15. Fractionation of Cu and Fe isotopes in metal-rich mine sites : biotic and abiotic processes

    Författare :Nathalie Pérez Rodríguez; Magnus Land; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cu and Fe isotopes; fractionation; tailings; plants; phytoremediation; organic amendments; soil bacteria; Cu and Fe cycle; covellite; redox processes; Applied Geology; Tillämpad geologi;

    Sammanfattning : After mineral exploitation the residual grinded and milled material, rich in sulphide minerals and heavy metals, is often left exposed to the atmospheric variables. This weathered mine waste material can lead to the formation of acid mine drainage (AMD) which has negative effects to the environment. LÄS MER