Sökning: "NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi"

Visar resultat 1 - 5 av 43 avhandlingar innehållade orden NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi.

  1. 1. Palaeoglaciology of the northeastern Tibetan Plateau

    Detta är en avhandling från Stockholm : Department of Physical Geography and Quaternary Geology, Stockholm University

    Författare :Jakob Heyman; Stockholms universitet.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Tibetan Plateau; palaeoglaciology; NATURAL SCIENCES Earth sciences Exogenous earth sciences Physical geography; NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi; NATURAL SCIENCES Earth sciences Exogenous earth sciences Quaternary geology; NATURVETENSKAP Geovetenskap Exogen geovetenskap Kvartärgeologi; Physical Geography; naturgeografi;

    Sammanfattning : This study concerns the palaeoglaciation of the northeastern Tibetan Plateau, with emphasis on the Bayan Har Shan (Shan = Mountain) in the headwaters of Huang He (Yellow River). To reconstruct past glacier development multiple techniques, including remote sensing, field investigations, cosmogenic exposure dating, and numerical modelling have been employed. LÄS MER

  2. 2. Diatoms as indicators of Holocene climate and environmental change in northern Sweden

    Detta är en avhandling från Umeå : Ekologi och geovetenskap

    Författare :Christian Bigler; Umeå universitet.; [2001]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical geography and sedimentology; diatoms; Holocene; paleolimnology; climate change; lake sediments; transfer functions; quantitative environmental reconstructions; northern Sweden; Abisko; Naturgeografi och sedimentologi; NATURAL SCIENCES Earth sciences Exogenous earth sciences Physical geography; NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi; naturgeografi; Physical Geography;

    Sammanfattning : The objective of the thesis was to explore the potential of diatoms (Bacillariophyceae) as indicators of Holocene climate and environmental change in northern Sweden (Abisko region, 68°21'N, 18°49'E). A modern surface-sediment calibration set including 100 lakes was developed and lake-water pH, sedimentary organic content (assessed by loss-on-ignition) and temperature were identified as most powerful environmental variables explaining the variance within the diatom assemblages. LÄS MER

  3. 3. Regulation of carbon dioxide emission from Swedish boreal lakes and the Gulf of Bothnia

    Detta är en avhandling från Umeå universitet

    Författare :Grete Algesten; Umeå universitet.; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical geography and sedimentology; lakes; boreal; Gulf of bothnia; CO2; NEE; DOC; mineralization; sediment; catchment; net heterotrophy; Naturgeografi och sedimentologi; NATURAL SCIENCES Earth sciences Exogenous earth sciences Physical geography; NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi; naturgeografi; Physical Geography;

    Sammanfattning : The global carbon cycle is subject to intense research, where sources and sinks for greenhouse gases, carbon dioxide in particular, are estimated for various systems and biomes. Lakes have previously been neglected in carbon balance estimations, but have recently been recognized to be significant net sources of CO2. LÄS MER

  4. 4. Production and emission of CO2 in two unproductive lakes in northern Sweden

    Detta är en avhandling från Umeå : Institutionen för Ekologi, miljö och geovetenskap, Umeå universitet

    Författare :Jan Åberg; Umeå universitet.; [2009]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; lake; carbon dioxide; organic carbon; inorganic carbon; boreal; arctic; DOC; DIC; CO2; emission; thermal stratification; allochthonous organic carbon; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology Freshwater ecology; NATURVETENSKAP Biologi Terrestrisk; limnisk och marin ekologi Limnisk ekologi; NATURAL SCIENCES Earth sciences Exogenous earth sciences Physical geography; NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi; naturgeografi; Physical Geography;

    Sammanfattning : Unproductive lakes are one of few natural landscape compartments with net release of carbon to the atmosphere. Lakes also generally decrease the net terrestrial carbon uptake, since most of the CO2 production in unproductive lakes are derived from organic carbon produced on land (e.g. in forests). LÄS MER

  5. 5. Carbon metabolism in clear-water and brown-water lakes

    Detta är en avhandling från Umeå : Institutionen för ekologi, miljö och geovetenskap, Department of Ecology and Environmental Sciences

    Författare :Jenny Ask; Umeå universitet.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; clear-water lakes; brown-water lakes; primary production; bacterial production; benthic; pelagic; net ecosystem production; allochthonous organic carbon; CO2; DOC; NATURAL SCIENCES Earth sciences Exogenous earth sciences Physical geography; NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology Freshwater ecology; NATURVETENSKAP Biologi Terrestrisk; limnisk och marin ekologi Limnisk ekologi; limnologi; Limnology; naturgeografi; Physical Geography;

    Sammanfattning : The trophic state of lakes is commonly defined by the concentration of nutrients in the water column. High nutrient concentrations generate high phytoplankton production, and lakes with low nutrient concentrations are considered low-productive. LÄS MER