Sökning: "Transport proxies"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden Transport proxies.

1. 1. Transport by Benthic Macrofauna: Functional Classification and Biogeochemical Response

   Författare :Stina Lindqvist; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Marine sediments; Early diagenesis; Bioturbation; Functional groups; Benthic fluxes; Imaging; Ecosystem function; Sediment reworking; Transport proxies; Fluorescent particles;

   Sammanfattning : Burrowing and reworking activities by benthic macrofauna regulate rates and pathways during organic matter mineralisation in bioturbated sediments. In so doing, they also affect the overall cycling of elements crucial in the biosphere (e.g. C, N, P, Fe, Mn and S). LÄS MER

3. 2. Networks of urban interaction - Growth and centrality in the complex geography of urban activity

   Författare :Alexander Hellervik; Chalmers tekniska högskola; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; accessibility; power law; urban activity; centrality; urban growth; transport infrastructure; spatial interaction; complex networks; Zipf’s law;

   Sammanfattning : How cities and regions grow and decline depend on technological, social and economic factors. Understanding the interplay of these forces is central in research efforts aiming to improve urban and transport planning. LÄS MER

4. 3. Diatom and Sedimentological Investigations on West Antarctic Shelf Sediment

   Författare :Charlotte Sjunneskog; Bjorg Stabell; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Antarctica; climate change; diatom abundance; geochemistry; Geovetenskap; Earth sciences; Geovetenskap; Quarternary Geology; kvartärgeologi;

   Sammanfattning : Climate and environmental change following the retreat of the last glacial ice sheet in the Antarctic Peninsula has been interpreted, employing diatom abundance, relative abundance of Chaetoceros resting spores and diatom assemblages as proxies. These together with sedimentological data and radiocarbon dating, suggest four major events that can be further subdivided. LÄS MER

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

   Författare :Christina E. Jonsson; Gunhild Rosqvist; Jan Seibert; Philip Barker; Stockholms universitet; []
   Nyckelord :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;

   Sammanfattning : 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). LÄS MER

7. 5. Manganese cycling in the Baltic Sea over the last ~8000 years: the influence of redox conditions on mineral formation and burial

   Författare :Conny Lenz; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Baltic Sea; sediments; hypoxia; redox conditions; manganese;

   Sammanfattning : The Baltic Sea is one of the largest brackish water bodies in the world and is suffering extensive environmental issues caused by eutrophication and warming climate. A halocline in the water column divides more saline bottom water fed by inflows through the narrow connection with the North Sea from the surface waters and inhibiting exchange of oxygen between the two water masses. LÄS MER