Sökning: "n-p ratio"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden n-p ratio.

1. 1. Biomass and Nutrient Status of Benthic Algae in Lakes

   Författare :Maria Kahlert; Alan Steinman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; benthic algae; patchiness; C:N:P ratio; nutrient recycling; grazer; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; limnologi; Limnology;

   Sammanfattning : For a complete picture of the lake ecosystem, it is necessary to understand the mechanisms regulating biomass and nutrient status (nutrient limitation, optimal supply, or surplus) of benthic algae, which are important primary producers and a food resource for grazers. This thesis gives an overview of the natural variation of benthic algae at different scales of space and time and on different substrates, and unravels some of the underlying factors. LÄS MER

3. 2. The synthesis of chiral bidentate (N,N), (N,P) and (N,O) ligands and their use in metal-mediated asymmetric carbon-carbon bond formation

   Författare :Fredrik Johansson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Chemistry; Kemi; organisk kemi; Organic Chemistry;

   Sammanfattning : This thesis covers three projects based on the metal-mediated formation of new chiral centers in the prescence of chiral ligands. The first project, involving (N,N)- ligands, concerns the synthesis of some (C2-symmetric bis(aziridine) ligands and the use of these in the addition of organolithium reagents to N-aryl protected imines leading to enantioselectivities of up to 89%. LÄS MER

4. 3. Recruitment from resting stages among bloom-forming cyanobacteria

   Författare :Annika Ståhl-Delbanco; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; marine biology; Hydrobiology; resting stage; Cyanobacteria; recruitment; algal bloom;

   Sammanfattning : Cyanobacteria are known to form heavy blooms in eutrophicated freshwaters and also form resting stages, associated with the sediments, during harsh growth conditions. These resting stages can serve as inoculum for pelagic populations and function as a potential source for bloom formations. LÄS MER

5. 4. Nutrient limitation and elemental ratios in Baltic Sea plankton

   Författare :Jakob Walve; Karin Lochte; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plankton; Östersjön; Ekosystem i vatten; Systems Ecology; systemekologi;

   Sammanfattning : Phytoplankton growth is frequently limited by the supply of nitrogen (N), phosphorus (P), or sometimes other elements. N2-fixing cyanobacteria are favoured by N limitation, which they may alleviate by adding new N to the ecosystem. LÄS MER

7. 5. The role of sediments in the biogeochemical cycles of nutrients in the Gulf of Riga

   Författare :Juris Aigars; Matti Perttilä; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biogeochemistry; biogeokemi;

   Sammanfattning : The sediment biogeochemistry of C, N, P and biologic silica (BSi) plays an important role in cycling of these elements in aquatic ecosystems. In shallow coastal and estuarine systems, water-sediment nutrient dynamics can influence biological processes (e.g., primary production) in overlying waters. LÄS MER