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Visar resultat 1 - 5 av 92 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Beyond carbon-limitation : A re-evaluation of the ecological role of photorespiration and direct oxygen photoreduction in seagrasses

    Författare :Pimchanok Buapet; Mats Björk; Ilana Berman-Frank; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon limitation; Chlorophyll fluorescence; Electron transport rate; Irradiance; Mehler reaction; Non-photochemical quenching; Photorespiration; Photosynthetic activity; Plant Physiology; växtfysiologi;

    Sammanfattning : Seagrasses living in shallow coastal waters are regularly subjected to changes in environmental conditions including the two essential factors for photosynthesis: dissolved inorganic carbon (DIC) and irradiance. This thesis focuses on the photosynthetic responses of seagrasses to carbon limitation induced by community metabolism and/or high light intensities. LÄS MER

  3. 2. Effects of temperature and terrestrial carbon on primary production in lake ecosystems

    Författare :Mohammed Hamdan; Jan Karlsson; Pär Byström; Erin R. Hotchkiss; Lars-Anders Hansson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lakes; primary production; benthic; pelagic; carbon dioxide limitation; light limitation; nutrient limitation; browning; warming; allochthonous carbon; grazing; trophic cascades;

    Sammanfattning : Climate warming is predicted to affect northern lake food webs in two ways: (1)directly via changes in water temperature and ice conditions, and (2) indirectlyvia changes in catchment characteristics and processes that influence input ofallochthonous coloured dissolved organic matter (cDOM) and nutrients. Input ofcDOM increases carbon dioxide (CO2) availability, causes brownification andreduced light conditions, and may increase nutrient availability especially forpelagic primary producers. LÄS MER

  4. 3. Nutrient Limitation of Bacterial Growth in Soil

    Författare :Fredrik Demoling; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ekologi; Ecology; Fertilization; Bacteria; Soil; Fungi; Thymidine or Leucine incorporation; Growth limitation; Phosphorus; Nitrogen; Carbon;

    Sammanfattning : Lack of carbon has been assumed to be the most common limiting factor for bacterial growth in soil, although there are reports of limitation by nitrogen and phosphorus. I have studied nutrient limitation of bacterial growth in soil using a novel technique, where thymidine or leucine incorporation is used to detect changes in growth rates after adding nutrients. LÄS MER

  5. 4. Metabolic analysis of shikimic acid producing Escherichia coli

    Författare :Louise Johansson; Avdelningen för kemiteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Kemiteknik och kemisk teknologi; Biokemi; metabolism; Chemical technology and engineering; transcriptome analysis; phosphorus-limitation; carbon-limitation; fed-batch; chemostat; batch; fermentation technology; Escherichia coli; shikimic acid; Biotechnology; Bioteknik; Metabolism; Biochemistry; principal component analysis; 2D-fluorescence spectrophotometry; metabolic flux analysis; carbon-rich;

    Sammanfattning : Shikimic acid production using recombinant E.coli has been developed during the past 15 years due to the increased demand of this product, primarily as a starting material for the anti-influensa medicine Tamiflu?. A detailed metabolic analysis of a shikimic acid producing E. LÄS MER

  7. 5. Factors regulating the origin and magnitude of carbon dioxide emissions from high-latitude lakes

    Författare :Hendricus Verheijen; Jan Karlsson; Cristian Gudasz; David A. Seekell; Marcus Klaus; Anne Ojala; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; lake; carbon dioxide; organic carbon; inorganic carbon; arctic; emission; environmental science; miljövetenskap; climate change; klimatförändringar; Physical Geography; naturgeografi;

    Sammanfattning : Lake ecosystems receive, transmit and process terrestrial carbon and thereby link terrestrial, aquatic and global carbon cycles. Most lakes evade CO2 to the atmosphere, but the annual magnitude of CO2 evasion, as well as sources and mechanisms underpinning CO2 evasion from lakes are still largely unresolved. LÄS MER