Sökning: "limnisk och marin ekologi Limnisk ekologi"

Visar resultat 16 - 20 av 94 avhandlingar innehållade orden limnisk och marin ekologi Limnisk ekologi.

1. 16. Mechanisms structuring the pelagic microbial food web : Importance of resource and predation

   Författare :Kristina Samuelsson; Agneta Andersson; Christiane Lancelot; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; pelagic microbial food web; bacteria; flagellates; ciliates; phytoplankton; mixotrophy; nutrient status; predation limitation; resource limitation; Baltic Sea; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : Temporal and spatial variations of pelagic microorganisms in the northern Baltic Sea were studied, as well as factors influencing their abundance and growth rates. Three main questions were asked 1) How does increased productivity influence the structure of the microbial food web? 2) Does predation limitation vary between trophic levels? 3) What is the relative importance of resource and predation limitation at different trophic levels?A field study in the northern Baltic Sea showed that dominating protozoa, flagellates and ciliates, increased with increasing primary productivity from north to south. LÄS MER

3. 17. Ecology and Evolution of Adaptive Morphological Variation in Fish Populations

   Författare :Richard Svanbäck; Peter Eklöv; Lennart Persson; Beren Robinson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; competition; functional morphology; individual specialization; inter-individual variation; intra-population variation; morphological variation; ontogeny; Perca fluviatilis; perch; phenotypic plasticity; predation; trade-offs; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : The work in this thesis deals with the ecology and evolution of adaptive individual variation. Ecologists have long used niche theory to describe the ecology of a species as a whole, treating conspecific individuals as ecological equivalent. LÄS MER

4. 18. Structural Growth in Mountain Birch, Betula pubescens ssp. czerepanovii

   Författare :Christina Borg; Brita Svensson; Staffan Karlsson; Seppo Neuvonen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : In this thesis, I have studied long shoot performance in the monoecious, deciduous tree Betula pubescens ssp. czerepanovii. LÄS MER

5. 19. Chemical Communication and Mate Choice : Investigations into the Meaning of a Fruit Fly Pheromone

   Författare :Björn G. Johansson; Göran Arnqvist; Fredrik Widemo; Anders Berglund; Allen Moore; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Drosophila grimshawi; sexual selection; pheromone; mate choice; lekking; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : Chemical signals are the most widely used form of sexual communication throughout the living world. However, there is in general little knowledge about what these signals actually communicate. The role of chemical signals, i.e. LÄS MER

7. 20. Links Between Structure and Function of Heterotrophic Aquatic Bacterial Communities

   Författare :Silke Langenheder; Lars Tranvik; Eva Lindström; David Kirchman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; heterotrophic bacteria; dissolved organic matter; diversity; community composition; ecosystem functioning; salinity; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : Heterotrophic bacteria utilize dissolved organic matter, and the carbon flow through an ecosystem depends on the fractions of the utilized carbon that is either respired or transferred to higher trophic levels. The major aim this thesis is to investigate 1) the relationship between composition and functioning in heterotrophic bacterioplankton communities and 2) the influence of environmental conditions on both parameters. LÄS MER