Sökning: "nutrient availability"

Visar resultat 1 - 5 av 129 avhandlingar innehållade orden nutrient availability.

  1. 1. Herbivores influence nutrient cycling and plant nutrient uptake : insights from tundra ecosystems

    Författare :Hélène Barthelemy; Olofsson Johan; Ellen Dorrepaal; Ann Milbau; Gough Laura; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Reindeer grazing; large herbivores; nutrient cycling; plant nutrient uptake; soil nutrient availability; arctic plant ecology; soil microbial communities; 15N stable isotopes; plant-soil interactions; plant quality; dung and urine.; Environmental Science; miljövetenskap; biology; biologi;

    Sammanfattning : Reindeer appear to have strong positive effects on plant productivity and nutrient cycling in strongly nutrient-limited ecosystems. While the direct effects of grazing on vegetation composition have been intensively studied, much less is known about the indirect effect of grazing on plant-soil interactions. LÄS MER

  2. 2. Phosphorus availability and microbial respiration across biomes : from plantation forest to tundra

    Författare :Camilla Esberg; Reiner Giesler; David A. Wardle; Bente J. Graae; Dan Binkley; Umeå universitet; []
    Nyckelord :phosphorus availability; microbial bioassay; soil respiration; microbial growth rate; Hedley fractionation; soil sorption; weathered soils; boreal forest; subarctic and tundra;

    Sammanfattning : Phosphorus is the main limiting nutrient for plant growth in large areas of the world and the availability of phosphorus to plants and microbes can be strongly affected by soil properties. Even though the phosphorus cycle has been studied extensively, much remains unknown about the key processes governing phosphorus availability in different environments. LÄS MER

  3. 3. The aquatic microbial food web and occurence of predation-resistant and potentially pathogenic bacteria, such as Francisella tularensis

    Författare :Johanna Thelaus; Agneta Andersson; Mats Forsman; Farooq Azam; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; bacteria; protozoa; ecology; predation; nutrient-availability; microbial food web; model; predation-resistance; Francisella; reservoir; biofilm formation; Freshwater ecology; Limnisk ekologi;

    Sammanfattning : All natural aquatic systems harbour a vast variety of microorganisms. In the aquatic microbial food web, the larger microorganisms (i.e. protozoa) feed on the smaller microorganisms (i. LÄS MER

  4. 4. Wild plants can improve their rhizosphere chemistry in acid soils

    Författare :Marion Schöttelndreier; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Växtekologi; Plant ecology; wild plants.; time pattern; soil heterogeneity; rhizotrons; rhizosphere; pH; oxalic acid; nutrient availability; malic acid; hydroponics; citric acid; 14C; biodegradation; acid soils; aluminium toxicity; Soil Science; agricultural hydrology; Lantbrukshydrologi; marklära; Plant biochemistry; Växtbiokemi;

    Sammanfattning : Growth conditions on acid soils may be hampered by low nutrient availability and phytotoxic Al (aluminium) concentrations. In this thesis I present my studies on adaptation mechanisms of wild plants to acid soils in the close root environment, the rhizosphere. LÄS MER

  5. 5. Disturbance regimes in dry sandy grasslands – past, present and future

    Författare :Anja Ödman; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Grassland conservation; sand steppe; land use history; conceptual model; soil disturbance; lime; nutrient availability; vascular plants; bryophytes; ground beetles; propagule supply;

    Sammanfattning : A number of sandy grassland habitats of interest for biodiversity conservation can be found in Europe. One such habitat is the threatened xeric sand calcareous grassland, which is home to a large number of endangered species. LÄS MER