Sökning: "web production"

Visar resultat 11 - 15 av 172 avhandlingar innehållade orden web production.

1. 11. Effects of temperature and terrestrial carbon on fish growth and pelagic food web efficiency

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

   Sammanfattning : 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. LÄS MER

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

   Författare :Johnny Berglund; Agneta Andersson; Ramon Massana; Umeå universitet; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

4. 13. Complexity and Change in a Simple Food Web : Studies in the Baltic Sea (FAO Area 27.IIId)

   Författare :Henrik Österblom; Sture Hansson; Robert W Furness; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Avian cholera; Bottom-up; Bycatch; Clupea harengus; Ecosystem; Food web; Gadus morhua; Halichoerus grypus; Regime shift; Sprattus sprattus; Top-down; Trophic cascade; Uria aalge; Marine ecology; Marin ekologi;

   Sammanfattning : An influence at one trophic level can result in dynamic impacts also on other components of a food web. These dynamics are known as trophic cascades, and can be both top-down and bottom-up. After a near-collapse of the Baltic cod Gadus morhua stock in the 1980s, its main prey sprat Sprattus sprattus increased dramatically. LÄS MER

5. 14. Toward a Sustainable Human-Robot Collaborative Production Environment

   Författare :Abdullah Alhusin Alkhdur; Lihui Wang; Gunnar Bolmsjö; KTH; []
   Nyckelord :vision sensor; 3D image processing; collision detection; safety; robot; kinematics; dynamics; collaborative assembly; energy consumption; optimisation; manufacturing; Production Engineering; Industriell produktion;

   Sammanfattning : This PhD study aimed to address the sustainability issues of the robotic systems from the environmental and social aspects. During the research, three approaches were developed: the first one an online programming-free model-driven system that utilises web-based distributed human-robot collaboration architecture to perform distant assembly operations. LÄS MER

7. 15. Climate change impacts on production and dynamics of fish populations

   Författare :Per Hedström; Pär Byström; Jan Karlsson; Peter Eklöv; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Temperature; terrestrial dissolved organic carbon; light extinction; GPP; recruitment; winter mortality; metabolism; cohort competition; fish production; fish biomass;

   Sammanfattning : Ongoing climate change is predicted to increase water temperatures and export of terrestrial dissolved matter (TDOM) to aquatic ecosystems influencing ecosystem productivity, food web dynamics and production of top consumers. Ecosystem productivity is mainly determined by the rates of primary production (GPP) in turn controlled by nutrients, light availability and temperature, while temperature alone affect vital rates like consumption and metabolic rates and maintenance requirements of consumers. LÄS MER