Search for dissertations about: "naturgeografi"

Showing result 6 - 10 of 335 swedish dissertations containing the word naturgeografi.

2. 6. Holocene climate and atmospheric circulation changes in northern Fennoscandia : Interpretations from lacustrine oxygen isotope records

   Author : Christina E. Jonsson; Gunhild Rosqvist; Jan Seibert; Philip Barker; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; oxygen isotope; diatom silica; lake sediment; atmospheric circulation; North Atlantic Oscillation; northern Fennoscandia; The Holocene; Little Ice Age; Physical geography; Naturgeografi; Physical Geography; naturgeografi;

   Abstract : This thesis investigates how variations in the oxygen isotopic composition of lake waters in northern Fennoscandia are recorded in lake sediment archives, especially diatoms, and how these variations can be used to infer past changes in climate and atmospheric circulation. Results from analyses of the oxygen isotopic composition of lake water samples (δ18Olakew) collected between 2001 and 2006 show that δ18O of northern Fennoscandian lakes is mainly controlled by the isotopic composition of the precipitation (δ18Op). READ MORE

4. 7. Late Quaternary climate and environmental change in the summer rainfall region of South Africa : A study using trees and wetland peat cores as natural archives

   Author : Elin Norström; Karin Holmgren; Michael Meadows; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; paleoclimate; Late Quaternary; pollen; stable isotopes; diatoms; phytoliths; dendroclimatology; South Africa; Physical geography; Naturgeografi; Physical Geography; naturgeografi;

   Abstract : This thesis contributes with information on past climate and environmental changes in South Africa’s summer rainfall region. The study is based on multi-proxy analyses on wetland peat cores and analyses of stable isotope composition (δ13C, δ18O) and wood anatomy in cross sections from subtropical trees (Breonadia salicina). READ MORE

5. 8. Waterborne sediment and pollutant transport into lakes and accumulation in lake sediments

   Author : Gull Olli; Gia Destouni; Ingmar Renberg; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Catchment; environmental projects; erosion; eutrophication; phosphorous transport and retention; soil transport; sediment accumulation; Physical geography; Naturgeografi; Physical Geography; naturgeografi;

   Abstract : The general objective of this thesis is to contribute to the knowledge of the transport of sediments and pollutants from catchments to downstream water recipient systems and their accumulation in these systems, such as lakes and lake sediments. One part of the thesis studies the importance of drainage reach morphology and water flow for the phosphorous (P) transport and retention in the reaches, and the main controlling processes of the P retention in the reach sediments. READ MORE

6. 9. Modelling water and solute flows at land-sea and land-atmosphere interfaces under data limitations

   Author : Yoshihiro Shibuo; Georgia Destouni; Jerker Jarsjö; Clifford Voss; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Submarine groundwater discharge; unmonitored flows; catchment hydrology; evapotranspiration; bathymetry; GIS; Aral Sea; nuclear waste repository sites; Physical geography; Naturgeografi; Physical Geography; naturgeografi;

   Abstract : Water and vapour flows from land to sea and the atmosphere are important for water resources, coastal ecosystems and climate. This thesis investigates possible methods for modelling these flows under often encountered unmonitored hydrological conditions and data limitations. READ MORE

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

   Author : Grete Algesten; Mats Jansson; Pirkko Kortelainen; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physical geography and sedimentology; lakes; boreal; Gulf of bothnia; CO2; NEE; DOC; mineralization; sediment; catchment; net heterotrophy; Naturgeografi och sedimentologi; Physical geography; Naturgeografi; naturgeografi; Physical Geography;

   Abstract : 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. READ MORE