Sökning: "sediment"

Visar resultat 1 - 5 av 506 avhandlingar innehållade ordet sediment.

  1. 1. Sediment resuspension : Impacts and extent of human disturbances

    Författare :Ingrid Tjensvoll; Clare Bradshaw; Torgeir Heggelund Bakke; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Marine Ecotoxicology; marin ekotoxikologi;

    Sammanfattning : Resuspension of sediment by anthropogenic disturbances is a concern due to the impacts it has on organisms and ecosystems. Bottom trawling is one major cause of sediment resuspension. A field study showed that a small trawl created a sediment plume 120 - 150 m wide and 15-18 m high (Paper 1). The sediment in the same study was highly contaminated. LÄS MER

  2. 2. Model Studies of Surface Waves and Sediment Resuspension in the Baltic Sea

    Författare :Anette Jönsson; Lars Rahm; Åsa Danielsson; Tarmo Soomere; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Surface waves; Wave model; Wave friction velocity; Resuspension; Sediment dynamics; Nitrogen fixation; Baltic Sea; Havsvågor; Östersjön; Oceanografi; Sediment; Oceanography; Oceanografi;

    Sammanfattning : Wave heights and periods of surface waves in the Baltic Sea have been modelled for a two-year period (1999-2000) with the wave model Hypas on an 11x11-km grid scale. There is a clear seasonal variation with higher waves during winter and lower during summer. LÄS MER

  3. 3. Diatom-rich sediment formation in lakes

    Författare :Petra Zahajská; Kvartärgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Silicon; silica; diatom; biogenic silica; lake; sediment; stable Si isotopes; Ge Si; Yellowstone; Northern Sweden;

    Sammanfattning : Unicellular photosynthetic golden algae called diatoms are one of the most abundant silicifying organisms. Diatoms take up silicon and build their frustules, in the form of biogenic silica (BSi), which have high preservation potential, and thus are found in sediments. LÄS MER

  4. 4. Sediment sources and transport pathways, Lithuanian coastal zone

    Författare :Milda Kairytè; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Nyckelord :sediment; grain size; mineralogy; Lithuania; coastal zone; provenance; geology;

    Sammanfattning : This thesis presents an investigation of recent sediments of the Lithuanian coastal zone, SE Baltic Sea. The main focus is upon the detailed documentation of grain size and mineralogy and the development of analytical methods using these essential and most common sediment parameters. LÄS MER

  5. 5. Lake sediment as environmental archive : natural and anthropogenic influence on the chronology of trace elements

    Författare :Evastina Grahn; Stefan Karlsson; Anders Düker; Bo Bergbäck; Örebro universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; lake sediment; environmental pollution; trace elements; chronology; diagenesis; Ag; Be; Ga; In; Pb; Sb; Tl; Environmental chemistry; Miljökemi; Enviromental Science; Miljövetenskap;

    Sammanfattning : The focus of this thesis is the historical pollution of some seldom-monitored trace elements (SMTEs; Ag, Be, Ga, In, Sb and Tl) that have been involuntarily released for several thousands of years but whose usage have increased during the industrial era. Sediment cores from four rural lakes in a south to north transect in central Sweden, and two urban lakes have been used as environmental archives for chronological studies. LÄS MER