Sökning: "dinoflagellate cysts"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden dinoflagellate cysts.

  1. 1. The Greenhouse - Icehouse Transition : a dinoflagellate perspective

    Författare :Caroline A. van Mourik; Henk Brinkhuis; Malgorzata Moczydlowska-Vidal; Stockholms universitet; []
    Nyckelord :Eocene - Oligocene; dinoflagellate cysts; biostratigraphy; paleoecology; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : Through the analysis of the stratigraphic and spatial distribution of organic walled dinoflagellate cysts (dinocysts) from climatologically and oceanographically key sites, this project aims to contribute to a better understanding of the Eocene-Oligocene (E/O) environmental changes and their timing. A central issue is to identify the global environmental changes which are responsible for the Eocene cooling and its underlying mechanisms with the focus on the Oligocene isotope-1 (Oi-1) event, thought to mark the onset of major Antarctic glaciation. LÄS MER

  3. 2. Dinoflagellate studies of the Upper Maastrichtian and Danian in southern Scandinavia

    Författare :Stefan Hultberg; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Three Swedish borehole cores and three Danish outcrop sections, spanning the Upper Maastrichtian and Danian, have been analyzed for dinoflagellates. Variations in the relative abundances of certain dinoflagellate species have been used to establish a quantitatively defined, high-resolution zonation for the Upper Maastrichtian of southern Scandinavia. LÄS MER

  4. 3. Cretaceous dinoflagellate cyst stratigraphy of the Höllviken 1 well, Scania, Southern Sweden

    Författare :Helena Westin; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The main aim of this thesis was to develop an improved biostratigraphical subdivision for part of the Lower and Upper Cretaceous section (Albian to Santonian) of Scania, Southern Sweden. Earlier attempts at biostratigraphic zonation within the sequence Cenomanian to Coniacian based on other micro- and macrofossils have proven difficult due to an impoverished fauna. LÄS MER

  5. 4. The role of resting cysts in the survival and succession of freshwater dinoflagellates

    Författare :Karin Rengefors; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Biologi; Biology; Biologi; limnologi; Limnology;

    Sammanfattning : Phytoplankton have adapted to survive in the variable and heterogeneous environment that is characteristic of lakes in temperate regions. One strategy for survival during periods unfavorable for growth is to form resting propagules. LÄS MER

  7. 5. The significance of sexuality and cyst formation in the life-cycles of four marine dinoflagellate species

    Författare :Rosa Figueroa; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cyst; Hydrobiology; akvatisk ekologi; marine biology; aquatic ecology; limnology; sexuality.; meiosis; Lingulodinium polyedrum; life-cyle; limnologi; Marinbiologi; Gymnodinium nolleri; Gymnodinium catenatum; Alexandrium catenella; dinoflagellates;

    Sammanfattning : Sexuality and cyst formation were studied in the marine dinoflagellate species Gymnodinium catenatum Graham, Gymnodinium nolleri Ellegaard ? Moestrup, Alexandrium catenella (Whedon et Kofoid) Balech, and Lingulodinium polyedrum (Stein) Dodge. The study included the morphological characterization of sexual stages and processes, the time and description of meiosis, the study of the length and regulation of the mandatory dormancy period of resting cysts, and the relationships among parental strains and cyst progeny at phenotypic and molecular levels. LÄS MER