Search for dissertations about: "FOOD LIMITATION"

Showing result 1 - 5 of 38 swedish dissertations containing the words FOOD LIMITATION.

2. 1. Pelagic microorganisms in the northern Baltic Sea : Ecology, diversity and food web dynamics

   Author : Johnny Berglund; Agneta Andersson; Ramon Massana; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; resource limitation; predation limitation; microbial food web; heterotrophic microorganisms; nanoflagellates; ciliates; protists; resource heterogeneity; chrysomonads; chrysophytes; group-specific PCR-DGGE primers; Baltic Sea; Marine ecology; Marin ekologi;

   Abstract : Heterotrophic microorganisms are important for the flow of carbon and nutrients in the sea. Bacteria, nanoflagellates and ciliates are relevant components of the pelagic food web. In order to be able to predict the outcome of e.g. READ MORE

4. 2. Mechanisms structuring the pelagic microbial food web : Importance of resource and predation

   Author : Kristina Samuelsson; Agneta Andersson; Christiane Lancelot; Umeå universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

5. 3. Mixing patterns in Rushton-turbine-agitated reactors

   Author : Fabrice Guillard; Livsmedelsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Food and drink technology; coherent mixing structure; geometrical analysis; dynamic structural analysis; conditional sampling; laser-induced fluorescence; mixing; stirred tank; Livsmedelsteknik;

   Abstract : This Ph.D. Thesis concerns the study of mixing in Rushton turbine agitated reactors. In industrial (bio)reactors, mixing is recognised as a limiting factor that significantly affects the performance of the process. READ MORE

6. 4. The role of terrestrial and phytoplankton-derived organic matter in planktonic food webs

   Author : Anja Wenzel; Ann-Kristin Bergström; Tobias Vrede; Maarten Boersma; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Daphnia; phytoplankton; heterotrophic bacteria; terrestrial particulate organic material; food quality; food quantity; fatty acids; oligotrophic; Light:Nutrient-Hypothesis; limnologi; Limnology;

   Abstract : Lakes are important global ecosystems and many of them are nutrient-poor (unproductive). Especially in northern boreal latitudes, lakes may be heavily subsidized by terrestrial organic material (t-OM) from peat layers in the catchment. READ MORE

7. 5. Effects of temperature and terrestrial carbon on primary production in lake ecosystems

   Author : Mohammed Hamdan; Jan Karlsson; Pär Byström; Erin R. Hotchkiss; Lars-Anders Hansson; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; lakes; primary production; benthic; pelagic; carbon dioxide limitation; light limitation; nutrient limitation; browning; warming; allochthonous carbon; grazing; trophic cascades;

   Abstract : Climate warming is predicted to affect northern lake food webs in two ways: (1)directly via changes in water temperature and ice conditions, and (2) indirectlyvia changes in catchment characteristics and processes that influence input ofallochthonous coloured dissolved organic matter (cDOM) and nutrients. Input ofcDOM increases carbon dioxide (CO2) availability, causes brownification andreduced light conditions, and may increase nutrient availability especially forpelagic primary producers. READ MORE