Search for dissertations about: "pelagic microbial food web"

Showing result 1 - 5 of 11 swedish dissertations containing the words pelagic microbial food web.

2. 1. 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

4. 2. 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

5. 3. Food web structures and carbon transfer efficiencies in a brackish water ecosystem

   Author : Kristin Dahlgren; Ulf Båmstedt; Agneta Andersson; Marja Koski; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Carbon transfer efficiency; Food web efficiency; zooplankton; production; pelagic; benthic; fatty acids; wax esters; Marine ecology; Marin ekologi;

   Abstract : Two differently structured food webs can be distinguished in the pelagic habitat of aquatic systems; the classical one (autotrophic) with phytoplankton as a base and the microbial food web (heterotrophic) with bacteria as a base. Energy (produced at the basal trophic level) reaches higher trophic levels, i.e. READ MORE

6. 4. Effects of temperature and terrestrial carbon on fish growth and pelagic food web efficiency

   Author : Robert Lefébure; Ulf Båmstedt; Pär Byström; Stefan Larsson; Agneta Andersson; Lars-Gösta Rudstam; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Attack rates; Bacterial production; Climate change; Critical resource density; Growth rates; Microbial food web; Three-spined stickleback;

   Abstract : Both temperature and terrestrial dissolved organic carbon (TDOC) have strong impacts on aquatic food web dynamics and production. Temperature affects vital rates of all organisms and terrestrial carbon has been shown to alter the dynamics of phytoplankton and bacterial production and affect the trophic structure of planktonic food webs. READ MORE

7. 5. Distribution and fate of polychlorinated biphenyls within the pelagic microbial food web

   Author : Petra Wallberg; Per Larsson; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biology; Biologi; zoologi; Zoology;

   Abstract : The composition and production of the plankton community in aquatic environments will in turn influence the food-web structure of larger predators, nutrient cycling, the sinking flux and, hence, the fate of hydrophobic organic contaminants. The aim of the research presented here was to study the distribution and fate of PCBs within the microbial food web, including bacteria, flagellates, ciliates, and phytoplankton. READ MORE