Search for dissertations about: "nifH"

Showing result 1 - 5 of 9 swedish dissertations containing the word nifH.

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

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

    Abstract : 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. READ MORE

  2. 2. Nitrogen fixation among marine bacterioplankton

    Author : Kjärstin H. Boström; Lasse Riemann; Åke Hagström; Grieg Steward; Högskolan i Kalmar; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Bacterioplankton; Nitrogen fixation; Bakterioplankton; Kvävefixering; Cyanobakterier; Kvävefixerande bakterier; Microbiology; Mikrobiologi; Mikrobiologi; Microbiology;

    Abstract : While bacterioplankton indisputably control vital biogeochemical paths in the cycling of carbon and nutrients in the world’s oceans, our knowledge about the functional and genetic diversity of bacterioplankton communities is negligible. In this thesis, molecular and more traditional microbiological methods were used to study the specific function of N2-fixation and in a general sense diversity of marine bacterioplankton species. READ MORE

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

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

    Abstract : 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. READ MORE

  4. 4. Diazotrophy and diversity of benthic cyanobacteria in tropical coastal zones

    Author : Karolina Bauer; Birgitta Bergman; Paul K. Hayes; Stockholms universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Marine cyanobacteria; benthic nitrogen fixation; diversity; diazotrophy; Lyngbya majuscula; Zanzibar; western Indian Ocean; Plant physiology; Växtfysiologi;

    Abstract : Discoveries in recent years have disclosed the importance of marine cyano-bacteria in the context of primary production and global nitrogen cycling. It is hypothesized here that microbial mats in tropical coastal habitats harbour a rich diversity of previously uncharacterized cyanobacteria and that benthic marine nitrogen fixation in coastal zones is substantial. READ MORE

  5. 5. Non-cyanobacterial nitrogen fixation insights in humic freshwater lakes and ponds

    Author : Leyden Fernandez-Vidal; Stefan Bertilsson; Sari Peura; David Walsh; Uppsala universitet; []
    Keywords : humic lakes; thaw ponds; non-cyanobacterial diazotrophs; nitrogen fixation; nitrogenase;

    Abstract : The biological basis of nitrogen fixation beyond the canonical role of Cyanobacteria is not well understood in freshwater ecosystems. To address this gap in knowledge, the main objective of this thesis is to study non-cyanobacterial nitrogen fixation in freshwater lakes and ponds. READ MORE