Sökning: "Lasse Riemann"

Hittade 5 avhandlingar innehållade orden Lasse Riemann.

  1. 1. 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

  3. 2. Substrate control of community composition and functional adaptation in marine bacterioplankton

    Författare :Julie Dinasquet; Lasse Riemann; Edward F. DeLong; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; marine microbial ecology; bacterioplankton; community composition; functional adaptation; dissolved organic carbon; bottom-up and top down factors; ctenophore Mnemiopsis leidyi; food-webs; Southern-Ocean; Antarctica; Mikrobiologi; Microbiology; Akvatisk ekologi; Aquatic Ecology;

    Sammanfattning : A drop of sea-water is teeming with a million of bacteria, on which pelagic food-webs and biogeochemical cycles depend. These bacteria thrive on a wide range of dissolved organic carbon (DOC) compounds produced through biotic and abiotic processes. LÄS MER

  4. 3. 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

  5. 4. Marine nitrogen fixation : Cyanobacterial nitrogen fixation and the fate of new nitrogen in the Baltic Sea

    Författare :Isabell Klawonn; Helle Ploug; Lasse Riemann; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; biogeochemistry; nitrogen cycling; nitrogen fixation; cyanobacteria; Baltic Sea; Marine Ecology; marin ekologi;

    Sammanfattning : Biogeochemical processes in the marine biosphere are important in global element cycling and greatly influence the gas composition of the Earth’s atmosphere. The nitrogen cycle is a key component of marine biogeochemical cycles. 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