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Visar resultat 1 - 5 av 147 avhandlingar som matchar ovanstående sökkriterier.
1. Herbivores influence nutrient cycling and plant nutrient uptake : insights from tundra ecosystems
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. Phosphorus availability and microbial respiration across biomes : from plantation forest to 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. The aquatic microbial food web and occurence of predation-resistant and potentially pathogenic bacteria, such as Francisella tularensis
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. Wild plants can improve their rhizosphere chemistry in acid soils
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. Disturbance regimes in dry sandy grasslands – past, present and future
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