Sökning: "diatom analysis"

Visar resultat 1 - 5 av 29 avhandlingar innehållade orden diatom analysis.

1. 1. Benthic diatoms in the Gulf of Bothnia : Community analysis and diversity

   Författare :Svenja Busse; Michael Sullivan; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Baltic Sea; Biodiversity; Biomass; Community ecology; Diatoms; Multivariate analysis; Navicula; Phytobenthos; Salinity gradient; Scale; Size; Water movement; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Ecological Botany; Ekologisk botanik;

   Sammanfattning : Benthic diatoms are valuable tools for biological monitoring and paleo-ecological reconstruction of past environmental conditions. This thesis aims at describing size-related properties of benthic diatoms and suggests that data assessment for community analysis can be improved by considering the importance of scale. LÄS MER

3. 2. Diatom and Sedimentological Investigations on West Antarctic Shelf Sediment

   Författare :Charlotte Sjunneskog; Bjorg Stabell; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Antarctica; climate change; diatom abundance; geochemistry; Geovetenskap; Earth sciences; Geovetenskap; Quarternary Geology; kvartärgeologi;

   Sammanfattning : Climate and environmental change following the retreat of the last glacial ice sheet in the Antarctic Peninsula has been interpreted, employing diatom abundance, relative abundance of Chaetoceros resting spores and diatom assemblages as proxies. These together with sedimentological data and radiocarbon dating, suggest four major events that can be further subdivided. LÄS MER

4. 3. Late Quaternary Biostratigraphy of Sediments of the Southeastern Baltic Sea

   Författare :Daiva Üsaityté; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; SE Baltic Sea; pollen analysis; Late Quaternary; numerical zonation; principal components analysis; Geovetenskap; Earth sciences; Geovetenskap; Quarternary Geology; kvartärgeologi;

   Sammanfattning : This thesis presents Late Quaternary biostratigraphy in the SE Baltic Sea, based on palynological data from fifteen sediment cores. An objective subdivision of the cores has been achieved by numerical zonation. Ordination has revealed a succession of pollen spectra that can be used for biostratigraphic correlation across the region. LÄS MER

5. 4. 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

7. 5. Changing Landscapes : An Environmental History of Chibuene, Southern Mozambique

   Författare :Anneli Ekblom; Paul Sinclair; Louis Scott; João Morais; Uppsala universitet; []
   Nyckelord :HUMANIORA; HUMANITIES; Archaeology; environmental history; archaeology; archaeobotany; paleoecology; vegetation history; pollen analysis; environmental management; environmental insecurity; resource utilisation; landscape; paleclimatology; trade; oral tradition; Mozambique; Vilanculos; Arkeologi; Archaeology subjects; Arkeologiämnen;

   Sammanfattning : This thesis analyses the dynamics of environmental change and its embeddedness in the long term interactions of social history and rainfall variability through the building of an environmental history of the Chibuene locality, the coastal plain of southern Mozambique, 5 km south of the town Vilanculos, from 400 AD to present day. Land-use practices over time are discussed on the basis of vegetation and land-use history based pollen analysis, charcoal influx and diatom analysis. LÄS MER