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Visar resultat 1 - 5 av 33 avhandlingar som matchar ovanstående sökkriterier.

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. Predation on marine pelagic bacteria : On the in situ rates, regulation and dynamics of bacterivory studied with a molecular genetic technique

   Författare :Johan Wikner; Åke Hagström; Caron David; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Marine; grazing; minicells; molecular genetics; method; predation rate; dynamics; bacterivore; predator-prey; mikrobiologi; Microbiology;

   Sammanfattning : .... LÄS MER

4. 3. Bacterioplankton in the light of seasonality and environmental drivers

   Författare :Carina Bunse; Jarone Pinhassi; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; marine bacteria; marine microbiology; seasonal succession; ocean acidification; proteorhodopsin; photoheterotrophy; microbial time series; Akvatisk ekologi; Aquatic Ecology; Mikrobiologi; Microbiology; Miljövetenskap; Environmental Science;

   Sammanfattning : Bacterioplankton are keystone organisms in marine ecosystems. They are important for element cycles, by transforming dissolved organic carbon and other nutrients. Bacterioplankton community composition and productivity rates change in surface waters over spatial and temporal scales. LÄS MER

5. 4. Nitrogen fixation among marine bacterioplankton

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

   Sammanfattning : 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. LÄS MER

7. 5. Effect of environmental factors on bacterioplankton community composition, diversity and functionality

   Författare :Johanna Sjöstedt; Lasse Riemann; Silke Langenheder; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; marine microbiology; bacterioplankton; community composition; diversity; functionality; environmental factors; disturbance; distribution; Mikrobiologi; Microbiology; Akvatisk ekologi; Aquatic Ecology;

   Sammanfattning : The ocean covers more than 70 % of the Earth surface and represents the largest ecosystem on Earth. Bacteria are an important part of the marine food web not only in remineralisation but also since they utilize dissolved organic matter (DOM) and make the energy available to higher trophic levels. LÄS MER