Sökning: "crater lake"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden crater lake.

  1. 1. Diatoms in Lake Duluti : Tracking Environmental Variability in Northern Tanzania during the Past 1000 Years

    Författare :Helena Öberg; Lars-Ove Westerberg; Karin Holmgren; Jan Risberg; Robert Marchant; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Paleolimnology; Tanzania; Diatoms; Climate change; Crater lake; Physical Geography; naturgeografi;

    Sammanfattning : The tropics are the regions which are least understood climatically and new data on past climate variability is necessary for reliable future modeling of climate change. This thesis contributes with new paleoenvironmental information from a small crater lake in northern Tanzania and provides an additional link between the integrated history of climate, environment and socioeconomic variability in tropical Africa. LÄS MER

  3. 2. Geology of Lagoa das Furnas, a crater lake on São Miguel, Azores archipelago

    Författare :Thommy Andersson; Otto Hermelin; Martin Jakobsson; Alasdair Skelton; Erik Sturkell; Richard Gyllencreutz; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lagoa das Furnas; Azores; crater lake; geophysical mapping; tephrochronology; volcanic dome; Marine Geology; maringeologi;

    Sammanfattning : In this thesis, the results from a geophysical mapping and coring campaign of Lagoa das Furnas are presented. Specific focus is placed on the origin of a subaqueous volcanic cone mapped in the southern part of the lake. LÄS MER

  4. 3. Past environmental and climate changes in northern Tanzania : Vegetation and lake level variability in Empakaai Crater

    Författare :Maria Ryner; Karin Holmgren; Peter Kuhry; Lars-Ove Westerberg; Henry Lamb; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; palaeoecology; palaeolimnology; physical and societal factors; Holocene; Tanzania; Lake Emakat; Engaruka; Earth sciences; Geovetenskap; Physical Geography; geografi med naturgeografisk inriktning;

    Sammanfattning : This thesis presents palaeoenvironmental data from equatorial Africa covering two important time intervals; i) the warming period forming the Pleistocene/Holocene transition and ii) the last millennium. The Empakaai Crater, in northern Tanzania contains a lake from where sediment cores, spanning two time-slices 14.8-9. LÄS MER

  5. 4. Linking lake variability, climate, and human activity in Basotu, Tanzania

    Författare :Lindsey Higgins; Lars-Ove Westerberg; Jan Risberg; Sarah Davies; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tanzania; crater lake; climate change; land-use change; water resources; environmental variability; diatoms; paleolimnology; chronology; Physical Geography; naturgeografi;

    Sammanfattning : Paleoenvironmental investigations establish important baseline knowledge of the natural variability of lake systems, to better understand human impacts on the landscape, and the effects of climate change on water resources. By combining long-term environmental history with investigations into modern land use patterns and climatological events, a wider perspective can be reached that has practical applications in water governance. LÄS MER

  7. 5. 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