Sökning: "N-cycle"
Visar resultat 1 - 5 av 10 avhandlingar innehållade ordet N-cycle.
1. Character and Function of Anammox Bacteria under Environmental Stress
Sammanfattning : During the last few decades observations of novel processes involved in nitrogen transformations have fundamentally challenged the view of pathways and controlling mechanisms during local and global nitrogen cycling. Anaerobic ammonium oxidation (anammox) constitutes one of these new pathways where autotrophic bacteria oxidize ammonium by nitrite to dinitrogen gas under anaerobic conditions. LÄS MER
2. The Role of Carbon-Nitrogen Interactions for Terrestrial Ecosystem Dynamics under Global Change - a modelling perspective
Sammanfattning : The nature of future climate change will depend on anthropogenic emissions of CO2, as well as climate- and CO2-mediated feedbacks through carbon (C) cycling in both terrestrial ecosystems and oceans. Terrestrial ecosystems remove presently about 25% of the anthropogenic CO2 fossil-fuel and land-use change emissions, but to attribute which mechanisms cause this uptake, and the key regions where it occurs, is a challenging task. LÄS MER
3. The Nitrogen Cycle in Soil - Climate Impact and Methodological Challenges in Natural Ecosystems
Sammanfattning : Nitrogen (N) is a fundamental element for life, and limiting in many terrestrial ecosystems. In non-N-fertilized ecosystems, the N inputs can be low, and the nutrient availability for plants is determined by the internal cycling of N. LÄS MER
4. Symbioses between cyanobacterial communities and feather mosses in boreal forests and consequences for dinitrogen fixation
Sammanfattning : Feather moss-cyanobacteria associations, although still poorly understood, are recognised as essential for the regulation of nitrogen (N) input into N-limited ecosystems such as boreal forests due to their ability to carry out N2-fixation. This thesis aimed to investigate the diversity and composition of feather moss-associated cyanobacterial communities, the mechanisms by which cyanobacterial colonisation on mosses occurs and the fate of the N that they fix, and how various combinations of biotic and abiotic conditions influence cyanobacterial N2-fixation activity. LÄS MER
5. Ecosystems in the Anthropocene: the role of cropland management for carbon and nitrogen cycle processes
Sammanfattning : Through deforestation and conversion of natural ecosystems to croplands and pastures, have humans released vast amounts of carbon (C) dioxide (CO2) into the atmosphere. Roughly one third of the cumulative anthropogenic emissions until today stem from these practices, the remainder being mostly due to fossil fuel combustion. LÄS MER
