Sökning: "diatoms"

Visar resultat 16 - 20 av 85 avhandlingar innehållade ordet diatoms.

  1. 16. Linking lake variability, climate, and human activity in Basotu, Tanzania

    Författare :Lindsey Higgins; Lars-Ove Westerberg; Jan Risberg; Sarah Davies; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tanzania; crater lake; climate change; land-use change; water resources; environmental variability; diatoms; paleolimnology; chronology; Physical Geography; naturgeografi;

    Sammanfattning : Paleoenvironmental investigations establish important baseline knowledge of the natural variability of lake systems, to better understand human impacts on the landscape, and the effects of climate change on water resources. By combining long-term environmental history with investigations into modern land use patterns and climatological events, a wider perspective can be reached that has practical applications in water governance. LÄS MER

  3. 17. Environmental history in southern Mozambique : Reconstruction of flooding events, hydroclimate and sea-level dynamics since mid-Holocene

    Författare :Sandra Raúl Sitoe; Jan Risberg; Elin Norström; Lars-Ove Westerberg; John Compton; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Southern Africa; Limpopo River floodplain; flooding event; sea-level change; climate change; diatoms; phytoliths; mineral magnetics; grain-size; radiocarbon dating; kvartärgeologi; Quaternary Geology;

    Sammanfattning : The aim of this thesis has been to reconstruct paleoenvironment, paleohydrology and paleoclimate in coastal southern Mozambique, with emphasis on tracing past flooding events on the lower Limpopo River floodplain. In order to extend flood chronologies beyond periods covered by instrumental data, sediments from lakes on the floodplain were studied (Lake Lungué, Coassane Oxbow, Lake Magandane and Lake Soane). LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  5. 19. Phenotypic and Genotypic responses in the planktonic diatom Skeletonema marinoi - Effects of Natural Processes and Anthropogenic Stressors

    Författare :Susanna Gross; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diatoms; genotype; phenotype; resting cell; eutrophication; spring bloom; diversity; grazing; adaptation; phytoplankton; microalgae; Skeletonema;

    Sammanfattning : Diatoms are one of the most diverse and abundant phytoplankton taxa and are highly important as primary producers, accounting for nearly half of the marine primary production and constituting the base in the marine food web. Despite their high dispersal potential they are genetically diverse and display genetically structured populations. LÄS MER

  7. 20. Holocene environmental changes and climate variability in the Eastern Mediterranean : Multiproxy sediment records from the Peloponnese peninsula, SW Greece

    Författare :Christos Katrantsiotis; Stefan Wastegård; Rienk Smittenberg; Jan Risberg; Elin Norström; Sherilyn Fritz; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mediterranean; Greece; Peloponnese; Holocene; sediments; diatoms; n-alkanes; stable isotopes; tectonics; climate variability; monsoons; NAO; NCP; Physical Geography; naturgeografi;

    Sammanfattning : This thesis presents multiproxy reconstructions of the mid to late Holocene climate and environmental changes in the Peloponnese peninsula, SW Greece. The combined dataset consists of diatom, biomarker and X-ray fluorescence spectrometry (XRF) elemental data in radiocarbon-dated sediment cores taken from the Agios Floros fen and the Gialova Lagoon in SW Peloponnese and the Ancient Lake Lerna in NE Peloponnese. LÄS MER