Sökning: "environmental gradient"

Visar resultat 11 - 15 av 209 avhandlingar innehållade orden environmental gradient.

  1. 11. Mercury cycling in the global marine environment

    Författare :Michelle Nerentorp; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; sea ice; air; seasonal and spatial variation; snow; Mercury cycling; seawater; mercury flux;

    Sammanfattning : Mercury is a globally distributed contaminant that exists in the atmosphere in its elemental form as a stable monoatomic gas. Having a residence time of around one year in air allows it to be transported far from emission sources and end up in polar ecosystems. LÄS MER

  3. 12. Palsa Growth and Decay in Northern Sweden : Climatic and Environmental Controls

    Författare :Frieda S. Zuidhoff; Jonas Åkerman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; ground thermal properties; palsas; permafrost degradation; peat porosity; Sweden; vegetation.; Geovetenskap; Earth sciences; Geovetenskap; naturgeografi; Physical Geography;

    Sammanfattning : This thesis outlines the development and decay of palsas in northern Sweden in relation to climatic and environmental factors. Palsas were investigated on morphology, vegetation, peat porosity, ground temperature and local climate in four bogs situated on a north-south gradient in northern Sweden. LÄS MER

  4. 13. Acidification of Swedish forest soils : evaluation of data from the Swedish forest soil inventory

    Författare :Johan Iwald; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Acidification of forest soils in Sweden has negatively affected nutrient status and caused toxic effects on biota. The aim of this thesis was to investigate potential impacts of two drivers of acidification of forest soils in Sweden: (1) tree growth with subsequent harvest and (2) deposition of sulphur and nitrogen compounds. LÄS MER

  5. 14. Quantifying ecological resilience in lakes – bridging theory and management

    Författare :Didier Ludovic Baho; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Ecological resilience, defined as the capacity of an ecosystem to withstand disturbances without losing original structures, processes and functions, has remained elusive and challenging to quantify. In this thesis, two methods were used to assess the resilience of aquatic communities to different stressors and management practices. LÄS MER

  7. 15. Carbon Emissions from Western Siberian Inland Waters

    Författare :Svetlana Serikova; Jan Karlsson; Oleg S. Pokrovsky; Hjalmar Laudon; Peter Raymond; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; carbon; carbon dioxide; methane; carbon emissions; river; lake; inland waters; permafrost; Siberia; Limnology; limnologi;

    Sammanfattning : Inland waters (i.e. rivers, streams, lakes, ponds) emit carbon (C) into the atmosphere. The magnitude of global inland water C emission has been estimated to equal the global ocean C sink, thus making inland waters an important component of the global C cycle. LÄS MER