Search for dissertations about: "diatoms"

Showing result 6 - 10 of 84 swedish dissertations containing the word diatoms.

2. 6. Single cell carbon and nitrogen dynamics in chain forming diatoms, including their resting stage

   Author : Rickard Stenow; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Diatoms; Resting stages; N cycling; Chain formation; Secondary ion mass spectrometry SIMS ;

   Abstract : The oceans are a fundamental part of all life on earth, accounting for more than half of Earth’s oxygen production. The ocean is also key to long term carbon dioxide sequestration. Diatoms are a group of phytoplankton differentiated by their silica shell/frustule and account for ~20% of global primary production. READ MORE

4. 7. Experimental Studies on the Regulation of Pigment Dynamics in Phytoplankton and Copepods by Dissolved Inorganic Nutrients

   Author : Lies Van Nieuwerburgh; Pauli Snoeijs; Ulf Båmstedt; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biology; Astaxanthin; Baltic Sea; carotenoids; diatoms; eutrophication; food web; mesocosms; microalgae; M74 syndrome; oxidative stress; phytoplankton blooms; zooplankton; Biologi; Biology; Biologi;

   Abstract : This thesis examines the role of dissolved inorganic nutrients in generating changes in phytoplankton community and pigment composition and if such changes can affect the production of the antioxidant astaxanthin in the ecosystem via pelagic copepods. The background of my studies is the possible relationship between eutrophication and a reproductive disturbance in Baltic populations of Atlantic salmon (M74), which is associated with astaxanthin and thiamine deficiencies and oxidative stress. READ MORE

5. 8. Grazer-induced responses in marine phytoplankton

   Author : Johanna Bergkvist; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; phytoplankton; defence; dinoflagellate; diatoms; paralytic shellfish toxins; polyunsaturated aldehydes; chain formation;

   Abstract : Phytoplankton are the most important primary producers in the world’s oceans, yet little is known of how they avoid the constant threats from the pelagic grazers. From land it is well known that plants defend themselves by having thorns or producing compounds unpalatable to grazers. READ MORE

6. 9. Long-term development of subalpine lakes : effects of nutrients, climate and hydrological variability as assessed by biological and geochemical sediment proxies

   Author : Manuela Milan; Christian Bigler; Monica Tolotti; Richard Bindler; Krystyna Szeroczyńska; Atte Korhola; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Paleolimnology; diatoms; Cladocera; sub-fossil pigments; geochemistry; wavelengthdispersive X-ray fluorescence spectroscopy; Lake Garda; Lake Ledro; reference conditions; nutrient enrichment; climate change; hydrological regime.;

   Abstract : Sediment records of two Italian subalpine lakes (Lake Garda and Lake Ledro) were analyzed in order to reconstruct their ecological evolution over the past several hundred years. A multi-proxy and multi-site approach was applied in order to disentangle the effects of local anthropogenic forcings, such as nutrients, and climate impacts on the two lakes and their catchments. READ MORE

7. 10. Isotope-based reconstruction of the biogeochemical Si cycle : Implications for climate change and human perturbation

   Author : Xiaole Sun; Carl-Magnus Mörth; Christoph Humborg; Per Andersson; Brian Fry; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; diatoms; biogenic silica BSi ; dissolved Si DSi ; Si isotope fractionation; the Baltic Sea; geokemi; Geochemistry;

   Abstract : The global silicon (Si) cycle is of fundamental importance for the global carbon cycle. Diatom growth in the oceans is a major sequestration pathway for carbon on a global scale (often referred to as the biological pump). READ MORE