Search for dissertations about: "nifH"

Showing result 6 - 10 of 10 swedish dissertations containing the word nifH.

  2. 6. 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

  4. 7. Functional genomics of the Baltic Sea cyanobacterium Nodularia spumigena in relation to nitrogen fixation, heterocyst differentiation and toxin production

    Author : Simina Vintila; Rehab El-Shehawy; Peter Lindblad; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; cyanobacteria; Nodularia; nitrogen fixation; heterocyst; nitrogenase; ammonium; phosphate; nodularin; Baltic Sea; Plant physiology; Växtfysiologi; Plant Physiology; växtfysiologi;

    Abstract : Nodularia spumigena is a filamentous, heterocystous cyanobacterium that dominates the annual, toxic cyanobacterial blooms in the Baltic Sea. The blooms are believed to have increased in recent years, due to eutrophication by phosphate and/or nitrogen. Toxicity of these blooms is well-documented and attributed to the hepatotoxin nodularin. READ MORE

  5. 8. Biodiversity and Ecosystem Functioning : What Diversity? Which Functioning?

    Author : Fabian Roger; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecology; Biodiversity; Ecosystem functioning; Multifunctionality; Microbial Ecosystems;

    Abstract : We share our planet with an estimated 8.7 million eukaryotic species and an uncountable number of bacteria and archaea. But that amazing diversity is under threat from overexploitation, habitat destruction and climate change. This realization has lead ecologists to study the consequences of species loss. READ MORE

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

    Author : Andrea Caputo; Rachel Ann Foster; Monika Quinones Winder; Ramon Massana; Stockholms universitet; []
    Keywords : 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;

    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

  7. 10. Significance of N2 fixing planktonic symbioses for open ocean ecosystems

    Author : Marcus Stenegren; Rachel A. Foster; Agneta Andersson; Stockholms universitet; []
    Keywords : 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;

    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