Search for dissertations about: "iron speciation"

Showing result 1 - 5 of 34 swedish dissertations containing the words iron speciation.

  2. 1. Drivers of increasing iron concentrations in freshwaters

    Author : Caroline Björnerås; Enhet akvatisk ekologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Järn; Akvatisk ekologi; Biogeokemi; Brunifiering; Iron; Freshwaters; Biogeochemistry; Brownification; Iron biogeochemistry; Browning; Freshwaters;

    Abstract : Iron (Fe) concentrations are increasing in freshwaters (lakes and streams) in Sweden, as well as in other regions in northern Europe. Together with increasing concentrations of organic matter, Fe is contributing to the ongoing browning of freshwaters, which may have serious ecological consequences and implications for ecosystem services. READ MORE

  4. 2. Chemical Speciation of Sulfur and Metals in Biogas Reactors : Implications for Cobalt and Nickel Bio-uptake Processes

    Author : Sepehr Shakeri Yekta; Bo Svensson; Ulf Skyllberg; Åsa Danielsson; Charles Banks; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Biogas; Anaerobic digestion; Chemical speciation; bio-uptake; Sulfur; Iron; Cobalt; Nickel; Biogas; Anaerob nedbrytning; Kemisk speciering; Bio-upptag; Svavel; Järn; Kobolt; Nickel;

    Abstract : A balanced supply of micronutrients, including metals such as iron (Fe), cobalt (Co), and nickel (Ni), is required for the efficient and stable production of biogas. During biogas formation, the uptake of micronutrient metals by microorganisms is controlled by a complex network of biological and chemical reactions, in which reduced sulfur (S) compounds play a central role. READ MORE

  5. 3. Varved lake sediments and diagenetic processes

    Author : Veronika Gälman; Ingemar Renberg; Daniel Conley; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Varved annually laminated lake sediment; diagenesis; varve appearance; iron; sulfur; chemical speciation; iron cycling; carbon; nitrogen; stabile isotopes; δ13C; δ15N; Earth sciences; Geovetenskap;

    Abstract : Varved (annually laminated) sediments are of great interest for inference of past environmental conditions, as they provide dated records with high time resolution. After deposition, the sediment varves are affected by diagenesis; i.e., chemical, physical and biological changes that occur within the sediment. READ MORE

  6. 4. Unraveling the importance of thiol compounds on mercury speciation, uptake and transformation by the iron-reducer Geobacter sulfurreducens

    Author : Mareike Franziska Gutensohn; Erik Björn; Ulf Skyllberg; Jeffra K. Schaefer; Vera Slaveykova; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; mercury; low molecular mass thiols; speciation; uptake; methylation; reduction; Hg 0 ; Hg II ; MeHg; Geobacter sulfurreducens; ICP-MS; LC-MS MS; X-ray absorption spectroscopy; cell physiology;

    Abstract : The biogenic methylation of inorganic, divalent mercury (Hg(II)) by methylating microorganisms leads to formation and bioaccumulation of monomethyl mercury (MeHg) in the environment and can cause severe damage to ecosystems and human health. Diverse microorganisms carry the gene sequence hgcAB and are able to methylate Hg(II) intracellularly. READ MORE

  7. 5. Iron and aluminium speciation in Swedish freshwaters : Implications for geochemical modelling

    Author : Carin Sjöstedt; Jon Petter Gustafsson; Peggy O'Day; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geochemical equilibrium modelling; pH; adsorption to ferrihydrite; metal-NOM complexation; liming; EXAFS spectroscopy;

    Abstract : Speciation governs transport and toxicity of trace metals and is important to monitor in natural waters. Geochemical models that predict speciation are valuable tools for monitoring. They can be used for risk assessments and future scenarios such as termination of liming. READ MORE