Sökning: "Physical geography"
Visar resultat 1 - 5 av 375 avhandlingar innehållade orden Physical geography.
Sammanfattning : The study of the surface mass balance of valley glaciers has a long history but one that is dogged by uncertainty and errors, and uncertainty about those errors. These problems are acknowledged by the glaciological community and have been examined and formalised in several publications. LÄS MER
Sammanfattning : The global carbon cycle is subject to intense research, where sources and sinks for greenhouse gases, carbon dioxide in particular, are estimated for various systems and biomes. Lakes have previously been neglected in carbon balance estimations, but have recently been recognized to be significant net sources of CO2. LÄS MER
Sammanfattning : The objective of the thesis was to explore the potential of diatoms (Bacillariophyceae) as indicators of Holocene climate and environmental change in northern Sweden (Abisko region, 68°21'N, 18°49'E). A modern surface-sediment calibration set including 100 lakes was developed and lake-water pH, sedimentary organic content (assessed by loss-on-ignition) and temperature were identified as most powerful environmental variables explaining the variance within the diatom assemblages. LÄS MER
Sammanfattning : Maintaining species diversity, ecosystem functioning, and socioeconomic values requires continued ecosystem heterogeneity across scales. This thesis aims to bridge gaps between ecological theory, environmental goals, and practical application of sustainable forest management needed to maintain such heterogeneity. LÄS MER
Sammanfattning : Relict non-glacial surfaces occur in many formerly glaciated landscapes, where they represent areas that have escaped significant glacial modification. Frequently distinguished by blockfield mantles, relict non-glacial surfaces are important archives of long-term weathering and landscape evolution processes. LÄS MER