Search for dissertations about: "forests and lakes"

Showing result 1 - 5 of 19 swedish dissertations containing the words forests and lakes.

2. 1. Evaporation and Heat-flux Aggregation in Heterogeneous Boreal Landscapes

   Author : Tony Persson; Sven Halldin; Dimitris Melas; Deliang Chen; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Hydrology; land-surface processes; heterogeneity; surface fluxes; soil-water content; high latitudes; snow; lakes; climate; mesoscale model; NOPEX; WINTEX; Hydrologi; Hydrology; Hydrologi;

   Abstract : The boreal forests represent 8 % of all forested areas on the earth and have a significant role in the control of greenhouse gases and an impact on global climate change. The main objective of this thesis is to increase the understanding of how evaporation and heat-flux processes in the boreal forest zone are affecting the regional and global climate. READ MORE

4. 2. Radionuclide transport in the boreal landscape : Uranium, thorium and other metals in forests, wetlands and streams

   Author : Fredrik Lidman; Hjalmar Laudon; Köhler Stephan; Oleg Pokrovsky; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; uranium thorium metal transport radionuclide wetland forest stream peat mire; naturgeografi; Physical Geography;

   Abstract : 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. READ MORE

5. 3. Catching Mercury : Mercury in Lake Vänern and Swedish catchments

   Author : Peter Wihlborg; Lars Hylander; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; mercury; deposition; budget; sediments; retention; catchments; dating; kvicksilver; deposition; budget; retention; avrinningsområden; datering; Water in nature and society; Vatten i natur och samhälle;

   Abstract : Vänern och dess sediment har under 1900-talet varit en av Sveriges mest kvicksilver (Hg) kontaminerade miljöer. 47 sedimentprofiler tagna 2001 analyserades for total Hg och temporala och spatiala mönster påvisades. Av den direkta Hg tillförseln 1918-2001 återfinns c:a 30 ton i bottensedimenten. READ MORE

6. 4. Reconstruction of Past European Land Cover Based on Fossil Pollen Data : Gaussian Markov Random Field Models for Compositional Data

   Author : Behnaz Pirzamanbein; Matematisk statistik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Spatial Statistics; Adaptive Markov Chain Monte Carlo; Dirichlet Observation; Confidence Region; Palaeoecology; Past Human Land Use; Stochastic Partial Differential Equation;

   Abstract : The aim of this thesis is to develop statistical models to reconstruct past land cover composition and human land use based on fossil pollen records over Europe for different time periods over the past 6000 years. Accurate maps of past land cover and human land use are needed when studying the interaction between climate and land surface, and the effects of human land use on past climate. READ MORE

7. 5. Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems

   Author : Martin Berggren; Mats Jansson; Michael L. Pace; Umeå universitet; []
   Keywords : lakes; streams; boreal; bacterial respiration; bacterial production; bacterial growth efficiency; allochthonous organic carbon; low molecular weight compounds; naturgeografi; Physical Geography;

   Abstract : Aquatic systems worldwide receive large amounts of organic carbon from terrestrial sources. This ‘allochthonous’ organic carbon (AlloOC) affects critical physical and chemical properties of freshwater ecosystems, with consequences for food web structures and exchange of greenhouse gases with the atmosphere. READ MORE