Sökning: "diazotrophs"

Visar resultat 1 - 5 av 12 avhandlingar innehållade ordet diazotrophs.

  1. 1. Distribution and activity of nitrogen-fixing bacteria in marine and estuarine waters

    Författare :Hanna Farnelid; Lasse Riemann; Jonathan Zehr; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 454-pyrosequencing; diazotrophs; heterotrophic bacteria; marine bacteria; marine microbial ecology; microbiology; nifH; nitrogenase; nitrogen fixation; PCR; qPCR; Mikrobiologi; Microbiology;

    Sammanfattning : In aquatic environments the availability of nitrogen (N) generally limits primary production. N2-fixing prokaryotes (diazotrophs) can convert N2 gas into ammonium and provide significant input of N into the oceans. Cyanobacteria are thought to be the main N2-fixers but diazotrophs also include a wide range of heterotrophic bacteria. LÄS MER

  3. 2. 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. 3. Genomic and morphological diversity of marine planktonic diatom-diazotroph associations : a continuum of integration and diversification through geological time

    Författare :Andrea Caputo; Rachel Ann Foster; Monika Quinones Winder; Ramon Massana; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phytoplankton; diatoms; cyanobacteria; diazotrophs; symbiosis; evolution; phylogenetics; confocal microscopy; qPCR; CARD-FISH; tropics; sub-tropics; Marine Ecology; marin ekologi;

    Sammanfattning : 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. LÄS MER

  5. 4. Genetic variability and nitrogenase activity of cyanobacterial communities associated with tropical seagrass meadows (western Indian Ocean)

    Författare :Mariam Hamisi; Birgitta Bergman; Thomas Lyimo; Beatriz Díez; Lucas Stal; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cyanobacteria; nitrogenase activity; diazotrophs; seagrass; western Indian ocean; Plant physiology; Växtfysiologi; Plant Physiology; växtfysiologi;

    Sammanfattning : Tropical seagrass ecosystems are highly productive and important for sustaining marine life and associated coastal societies. In this study, the diversity and role of nitrogen-fixing cyanobacteria associated with five common seagrass genera in coastal regions of the western Indian Ocean (WIO; Tanzania) were examined, as well as the impact of anthropogenic activities. LÄS MER

  7. 5. Trophic complexity of zooplankton–cyanobacteria interactions in the Baltic Sea : Insights from molecular diet analysis

    Författare :Nisha H. Motwani; Elena Gorokhova; Jakob Walve; Catherine Legrand; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; bloom-forming filamentous cyanobacteria; diazotrophs; picocyanobacteria; zooplankton; grazing; molecular diet analysis; stable isotopes; biochemical indices; Marine Ecology; marin ekologi;

    Sammanfattning : Blooms of nitrogen fixing cyanobacteria (NFC) occur in many freshwater and marine systems, including the Baltic Sea. By fixing dissolved nitrogen, they circumvent general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for non-diazotrophic primary producers and ultimately supporting secondary production. LÄS MER