Sökning: "peat accumulation"
Visar resultat 6 - 10 av 20 avhandlingar innehållade orden peat accumulation.
6. Subarctic ecosystem responses to climate, catchment and permafrost dynamics in the Holocene
Sammanfattning : This thesis assesses aspects of the wetland development, permafrost dynamics and associated changes in carbon and nutrient cycling of the Stordalen Mire in northern Sweden. Various ecological and biogeochemical analyses of one peat and two lake sediment sequences were conducted, including analyses of organic matter and carbonate content, mosses, diatoms, testate amoebae, pigments, carbon and nitrogen and their stable isotopes, near infrared spectroscopy and biogenic silica. LÄS MER
7. 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
8. Tree-limit ecotonal response to Holocene climate change in the Scandes Mountains of west-central Sweden
Sammanfattning : The aim of this thesis was to reconstruct the Holocene vegetational and climatic development in the Sylarna-Storulvån area, western Jämtland, in the central Scandes Mountains. Temporal trends and fluctuations in the elevation and vegetational character of the tree-limit ecotone were studied mainly by means of pollen and plant macrofossil analysis of two lake sediment sequences (Lakes Stentjärn and Spåime), located above the present-day tree-limit. LÄS MER
9. Holocene carbon and nitrogen accumulation rates and contemporary carbon export in discharge : a study from a boreal fen catchment
Sammanfattning : The contemporary role of mires in land-atmosphere exchange of carbon dioxide (CO₂) is the subject of intense scientific debate. Investigating patterns and mechanisms of variations in past carbon (C) accumulation rates as well as contemporary C fluxes of peatlands facilitates predictions of future mire C sink strength under a changing climate. LÄS MER
10. Radionuclide transport in the boreal landscape : Uranium, thorium and other metals in forests, wetlands and streams
Sammanfattning : The boreal landscape is complex mosaic of vast forests, lakes and wetlands. Through the landscape flows a fine network of streams and rivers, carrying dissolved and suspended material from atmospheric deposition and weathering of soils and bedrock to downstream recipients. LÄS MER