Sökning: "phosphorus availability"

Visar resultat 11 - 15 av 51 avhandlingar innehållade orden phosphorus availability.

  1. 11. The role of nutrients for stream ecosystem function in Arctic landscapes : drivers of productivity under environmental change

    Författare :Maria Myrstener; Ryan A. Sponseller; Reiner Giesler; Ann-Kristin Bergström; Tenna Riis; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nutrients; Stream; Arctic; Boreal; Primary productivity; Algae; Biofilm; Nutrient limitation; Nitrogen; Phosphorus;

    Sammanfattning : Arctic and sub-Arctic freshwaters are currently experiencing substantial ecosystem changes due to the effects of global warming. Global warming effects on these freshwaters include increasing water temperatures, altered hydrological patterns, shifts in riparian vegetation and changes in the export of nutrients and carbon from soils. LÄS MER

  3. 12. Consumption patterns and excretion in aquatic food websenrichment

    Författare :Anders Persson; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydrobiology; trophic interactions; translocation; biomanipulation; enrichment; phosphorus; model; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

    Sammanfattning : This thesis links biogeochemical cycling to classical ecology. Predictions derived from food chain theory, based on Lotka-Volterra type of interactions, were tested in aquatic environments with the main hypothesis that consumers affect lower levels of organization by both predation and excretion of limiting nutrients. LÄS MER

  4. 13. Remote sensing of grassland communities : integrated effects of soil nutrients and habitat age

    Författare :Oskar Löfgren; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Remote sensing; Plant ecology; semi-natural grassland; Nitrogen; Phosphorus; Semi-natural grassland; Plant ecology; Remote sensing; Nitrogen; Phosphorus; Spectral reflectance; grassland specialists; Succession;

    Sammanfattning : Semi-natural grasslands are characterized by high fine-scale plant species richness. The richest grassland communities, with many habitat-specialist species, are found in ancient grassland sites that have a long continuity of grazing management and low levels of soil nutrients. Grazed grasslands were widespread in the historical landscape. LÄS MER

  5. 14. Peatlands at a Threshold: Greenhouse Gas Dynamics in a Changing Climate

    Författare :Magnus Lund; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chamber; greenhouse gas; nitrous oxide; methane; carbon dioxide; carbon; bog; Peatland; mire; eddy covariance; nitrogen; phosphorus; fertilization;

    Sammanfattning : To be able to predict the strength of climate change and its consequences for mankind, it is of major importance to understand the contemporary greenhouse gas exchange of the terrestrial biosphere, as well as its response to changes in climate. To achieve such understanding both descriptive studies and manipulation experiments are required. LÄS MER

  7. 15. Soil phosphorus – a multidimensional resource that plays an important role for grassland plant species richness

    Författare :Jakob Sandberg; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; niche dimension; nutrient limitation; niche differentiation; competition; soil nitrogen; soil phosphorus; plant diversity; species richness; Grassland; land use; landscape scale;

    Sammanfattning : The semi-natural grassland habitats contain an important part of the plant diversity in Europe. Changes in farming practices have lead to drastic decreases in plant species richness. The aim of the present thesis is to contribute to the knowledge about mechanisms governing the plant species richness in grasslands with emphasis on soil nutrients. LÄS MER