Sökning: "kväve"

Visar resultat 6 - 10 av 124 avhandlingar innehållade ordet kväve.

  1. 6. Importance of tannins for responses of aspen to anthropogenic nitrogen enrichment

    Författare :Franziska Bandau; Benedicte Albrectsen; Michael Gundale; Lisbeth Josson; Umeå universitet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; aspen; foliar condensed tannins; genetic variability; anthropogenic nitrogen enrichment; plant growth; plant defense; litter decomposition; Populus tremula; asp; kondenserade tanniner; genetisk variabilitet; antropogent kväve; tillväxt; växtförsvar; förna nedbrytning; Populus tremula; Environmental Science; miljövetenskap; ekologisk botanik; Ecological Botany; Entomology; entomologi; Physiological Botany; fysiologisk botanik; Population Biology; populationsbiologi;

    Sammanfattning : Boreal forests are often strongly nitrogen (N) limited. However, human activities are leading to increased N inputs into these ecosystems, through atmospheric N deposition and forest fertilization. LÄS MER

  3. 7. Microbial mobilization and immobilization of soil nitrogen

    Författare :Per Bengtson; MEMEG; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Ekologi; growth rate; microbial activity; respiration; assimilation; immobilization; Nitrogen; mineralization;

    Sammanfattning : Microorganisms in forest ecosystems normally recycle nitrogen (N), such that gaseous losses and leaching are limited. Mobilization of organic N, including microbial N, and immobilization of inorganic N, especially NH4+, are the quantitatively most important N transformation processes. Various factors influence their rates, e.g. LÄS MER

  4. 8. G och K stjärnors effektiva temperaturer och deras kol-, kväve- och syrehalter

    Författare :Urban Olof Frisk; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This study is aimed at increasing our knowledge and understanding of the evolutionary stages during and after the main sequence phase. The study is based on new photometric and spectroscopic observations of stars in the region from the main sequence and up to the red giants. LÄS MER

  5. 9. Effects of inorganic nitrogen and organic carbon on pelagic food webs in boreal lakes

    Författare :Anne Deininger; Ann-Kristin Bergström; Jan Karlsson; Antonia Liess; Carolyn L. Faithfull; John A. Downing; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; autochthony; basal production; boreal; global change; dissolved organic carbon; food web efficiency; N deposition; phytoplankton; seston stoichiometry; whole lake enrichment; zooplankton; limnologi; Limnology;

    Sammanfattning : Anthropogenic activities are increasing inorganic nitrogen (N) loadings to lakes in the northern hemisphere. In many boreal lakes phytoplankton are N limited, wherefore enhanced N input may affect the productivity of pelagic food webs. LÄS MER

  7. 10. Soil-living archaea: Influence of pH, carbon and nitrogen on their abundance and activity

    Författare :Anna Sterngren; MEMEG; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Archaea; ammonia-oxidizing archaea; soil; AOA; AOB; root exudates; gross nitrification; qPCR; pH; carbon cycle; nitrogen cycle;

    Sammanfattning : During the last decade it has been discovered that around 2% of the soil-living prokaryotes belong to the domain Archaea. In many soils the most abundant archaeal group is the ammonia-oxidizing archaea (AOA) that, in addition to ammonia-oxidizing bacteria (AOB), preform the first and rate-limiting step in the nitrification process. LÄS MER