Search for dissertations about: "Rachel Foster"
Found 5 swedish dissertations containing the words Rachel Foster.
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1. Genomic and morphological diversity of marine planktonic diatom-diazotroph associations : a continuum of integration and diversification through geological time
Abstract : Symbioses between eukaryotes and nitrogen (N2)-fixing cyanobacteria (or diazotrophs) are quite common in the plankton community. A few genera of diatoms (Bacillariophyceae) such as Rhizosolenia, Hemiaulus and Chaetoceros are well known to form symbioses with the heterocystous diazotrophic cyanobacteria Richelia intracellularis and Calothrix rhizosoleniae. READ MORE
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2. Environmental conditions governing the distributions of symbiotic and free-living diazotrophic cyanobacteria in two tropical open oceans
Abstract : Di-nitrogen (N2) fixation plays a crucial role in oceanic carbon and nitrogen cycles and is important for marine biogeochemistry on regional and global scales. N2-fixing (diazotrophs) cyanobacteria are considered to contribute the most to marine nitrogen fixation, and thereby fuel the surrounding phytoplankton communities with bioavailable ammonia. READ MORE
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3. Significance of N2 fixing planktonic symbioses for open ocean ecosystems
Abstract : 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). READ MORE
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4. Molecular detection of abundance and activity of marine, symbiotic, N2-fixing cyanobacteria
Abstract : Marine primary productivity in large parts of the oceans is supported by nitrogen fixers (diazotrophs). Richelia, a genus of multiple closely related species of heterocystous filamentous cyanobacterial diazotrophs, are often found in symbioses with a few genera of diatoms. Several Richelia species: R. euintracellularis, R. READ MORE
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5. Factors influencing emission fluxes and bacterial enrichment in sea spray aerosols : Insights from laboratory and field studies
Abstract : Sea spray aerosol (SSA) is one of the major natural aerosol sources and is produced when wave breaking entrains air into ocean surface water, which subsequently breaks up into bubbles. These bubbles rise to the surface and can scavenge biogenic material. READ MORE