Sökning: "diatoms"
Visar resultat 6 - 10 av 85 avhandlingar innehållade ordet diatoms.
6. Single cell carbon and nitrogen dynamics in chain forming diatoms, including their resting stage
Sammanfattning : 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. LÄS MER
7. Experimental Studies on the Regulation of Pigment Dynamics in Phytoplankton and Copepods by Dissolved Inorganic Nutrients
Sammanfattning : 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. LÄS MER
8. Grazer-induced responses in marine phytoplankton
Sammanfattning : 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. LÄS MER
9. Long-term development of subalpine lakes : effects of nutrients, climate and hydrological variability as assessed by biological and geochemical sediment proxies
Sammanfattning : 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. LÄS MER
10. Isotope-based reconstruction of the biogeochemical Si cycle : Implications for climate change and human perturbation
Sammanfattning : 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). LÄS MER
