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Visar resultat 1 - 5 av 10 avhandlingar som matchar ovanstående sökkriterier.
1. Microbial Communities in Boreal Peatlands : Responses to Climate Change and Atmospheric Nitrogen and Sulfur Depositions
Sammanfattning : Myrmarker har en stor roll i regleringen av den globala kolbalansen och koncentrationerna av koldioxid och metan i atmosfären, vilket gör dem till speciellt viktiga ekosystem ur ett klimatförandringsperspektiv. Förändringar av myrmarker genom naturlig utveckling eller antropogen påverkan kan därför få långtgående störningar av myrars klimatreglerande funktion. LÄS MER
2. Production and emission of CO2 in two unproductive lakes in northern Sweden
Sammanfattning : Unproductive lakes are one of few natural landscape compartments with net release of carbon to the atmosphere. Lakes also generally decrease the net terrestrial carbon uptake, since most of the CO2 production in unproductive lakes are derived from organic carbon produced on land (e.g. in forests). LÄS MER
3. Peatland dynamics in response to past and potential future climate change : A regional modelling approach
Sammanfattning : The majority of the northern peatlands developed during the Holocene as a result of a positive mass balance between net primary productivity (NPP) and heterotrophic decomposition rates. Over that time they have sequestered a huge amount of carbon in terrestrial ecosystems. LÄS MER
4. Physical process effects on catchment-scale pollutant transport-attenuation, coastal loading and abatement efficiency
Sammanfattning : Pollutants follow various subsurface and surface water pathways from sources within a catchment to its outlet and may cause detrimental effects on downstream water quality and ecosystems. Along their different transport pathways through a catchment, pollutants may be attenuated subject to different physical and biogeochemical processes. LÄS MER
5. Long-term development, modeling and management of nutrient loading to inland and coastal waters
Sammanfattning : Environmental and water system protection and restoration require accurate knowledge and quantification of waterborne pollutant transport, retention-release and transformation processes taking place in the subsurface, river, lake and sea water systems, and at the interfaces between these systems. This thesis investigates the importance of spatial model resolution for such quantification and the possible long-term nutrient load development under different human perturbations and nutrient source management scenarios in the Swedish Norrström drainage basin, based on simulations with the GIS-based dynamic nutrient transport-attenuation model POLFLOW. LÄS MER