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Visar resultat 21 - 25 av 478 avhandlingar som matchar ovanstående sökkriterier.

1. 21. High-Resolution Seismics Methods Applied to Till Covered Hard Rock Environments

   Författare :Björn Bergman; Christopher Juhlin; Laust Börsting Pedersen; Ari Tryggvason; Ramon Carbonell; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geophysics; High-Resolution; Reflection Seismics; Tomography; Nuclear waste repository; Bedrock; Sediments; Geofysik; Geophysics; Geofysik;

   Sammanfattning : Reflection seismic and seismic tomography methods can be used to image the upper kilometer of hard bedrock and the loose unconsolidated sediments covering it. Developments of these two methods and their application, as well as identifying issues concerning their usage, are the main focus of the thesis. LÄS MER

3. 22. Studies of actinides in a superanoxic fjord

   Författare :Per Roos; Lund Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Geology; colloids.; TIMS; pore water; remobilisation; sediments; ultrafiltration; uranium; thorium; americium; plutonium; Anoxic; Framvaren; fjord; physical geography; Geologi; fysisk geografi;

   Sammanfattning : Water column and sediment profiles of plutonium, americium, thorium and uranium have been obtained in the superanoxic Framvaren fjord, southern Norway. The concentrations of bomb test fallout Pu, Am as well as 'dissolved' Th in the bottom water are the highest recorded in the marine environment. LÄS MER

4. 23. Fate and transport of POPs in the aquatic environment : with focus on contaminated sediments

   Författare :Sarah Josefsson; Karin Wiberg; Mats Tysklind; Kjell Leonardsson; Jonas S Gunnarsson; Jussi Kukkonen; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bioturbation; bioirrigation; bioaccumulation; secondary sources; buried contaminants; sediment remediation; active capping; thin-layer capping; Marenzelleria spp.; Baltic Sea; polychlorinated dibenzo-p-dioxins; polychlorinated dibenzofurans; polychlorinated biphenyls; hexachlorobenzene; octachloro¬styrene; polybrominated diphenyl ethers; PCDD Fs; PCBs; HCB; OCS; PBDEs; water sampling; passive sampling; particulate fraction; freely dissolved; apparently dissolved; colloid; organic carbon; activated carbon; lignin; sediment-to-water flux; spring bloom; Environmental chemistry; Miljökemi; Persistent organic compounds; Persistenta organiska föreningar; Environmental Science; miljövetenskap;

   Sammanfattning : Persistent organic pollutants (POPs) are hydrophobic substances that readily sorb to organic matter in particles and colloids instead of being freely dissolved in the water phase. This sorption affects the bio­availability and environmental transport of the POPs. LÄS MER

5. 24. Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments

   Författare :Tom Korsman; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Palaeolimnology; acidification history; alkalization; acid deposition; land-use; lake sediments; near infrared spectroscopy; diatoms; multivariate calibration; Sweden;

   Sammanfattning : This thesis presents temporal perspectives of lake acidification in Sweden. Sediment records have been used to study timing, trends and causes of acidification, and two different techniques for assessing past lake-water acidity are presented. LÄS MER

7. 25. Implications of land use on the carbon cycle - Impacts of long-term human activities on terrestrial organic matter input to aquatic ecosystems in southern Sweden

   Författare :Bingjie Yang; BECC: Biodiversity and Ecosystem services in a Changing Climate; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lignin phenols; pollen; Land Reconstruction Algorithm; terrestrial organic matter; southern Sweden; sediments;

   Sammanfattning : Human activities have a huge impact on the carbon cycle by modifying the landscape. Vegetation cover changes attributed to forest clearance and the expansion of agricultural land increases soil erosion, organic matter and other nutrient delivery from terrestrial to aquatic ecosystems. LÄS MER