Sökning: "Marine ecology"

Visar resultat 31 - 35 av 342 avhandlingar innehållade orden Marine ecology.

1. 31. Waterfowl herbivory on submerged macrophytes in eutrophic lakes

   Författare :Håkan Sandsten; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; limnology; Marinbiologi; limnologi; Hydrobiology; Växtekologi; Plant ecology; akvatisk ekologi; Djurekologi; Animal ecology; Anas; Fulica atra; Cygnus; alternative stable states; water depth; distribution; plant species composition; hydrophytes; propagule size; Herbivory; tuber; Potamogeton; marine biology; aquatic ecology;

   Sammanfattning : Submerged macrophytes are thought to stabilize clear-water states of shallow lakes. The aim of this thesis was to elucidate how waterfowl herbivory can affect abundance, distribution and species composition of submerged macrophytes in eutrophic lakes. LÄS MER

3. 32. Significance of N2 fixing planktonic symbioses for open ocean ecosystems

   Författare :Marcus Stenegren; Rachel A. Foster; Agneta Andersson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; nitrogen fixation; diazotrophs; symbiosis; DDA; cyanobacteria; qPCR; piecewise SEM; microarray; tropics; subtropics; marine; open ocean; Richelia; Calothrix; Marine Ecology; marin ekologi;

   Sammanfattning : Di-nitrogen (N2) fixers, also called diazotrophs, are able to reduce atmospheric N2 into bioavailable nitrogen, giving them an advantage in open ocean regions with low dissolved inorganic nitrogen concentrations. The focus of this thesis are three lineages of symbiotic heterocystous filamentous types (het-1, het-2 and het-3), that associate with several genera of microalgae called diatoms (collectively referred to as Diatom Diazotroph Associations, DDAs). LÄS MER

4. 33. Predator-prey interactions in freshwater systems: The importance of chemical communication

   Författare :Kajsa Åbjörnsson; Enhet akvatisk ekologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi; Hydrobiology; trophic cascades; non-lethal effects; benefits; costs; heredity; predator experience; alarmsubstances; dietary cues; amphibian larvae; invertebrates; visibility; fish; behaviour; Predator-prey; chemical cues;

   Sammanfattning : Predator released chemical cues provide a valuable source of information to prey organisms that can be used to alter their behaviour in order to reduce predation risk. In this thesis, I have examined under what circumstances chemical cues may be used by prey, and if prey discriminate between different cues. LÄS MER

5. 34. Behavioural ecology of Indo-Pacific bottlenose and humpback dolphins

   Författare :Eva Stensland; Per Berggren; Anders Angerbjörn; Elisabeth Slooten; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Behaviour; ecology; dolphins; Zanzibar; abundance; distribution; tourism; mixed-species groups; interspecific association; social interaction; swim-with-dolphin; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : Dolphins in East Africa face various threats, such as direct hunt, bycatch and habitat degradation. It is therefore important to undertake research that can facilitate necessary conservation and management actions to minimize these threats. LÄS MER

7. 35. Plumage Colours and the Eye of the Beholder : The Ecology of Colour and its Perception in Birds

   Författare :Olle Håstad; Mats Björklund; Innes Cuthill; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; ultraviolet; colour vision; opsin; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : Virtually all diurnal birds have tetrachomatic vision based on four different colour receptors. As a result, birds are potentially able to perceive their environment in twice as many colours as humans and four times as many colours compared to most other mammals, which are dichromatic. LÄS MER