Abstract

Modern and Late Quaternary oceanic assemblages of calcareous dinoflagellate cysts are often dominated by the species Calciodinellum albatrosianum, Leonella granifera and Pernambugia tuberosa. Their distribution in surface sediments of the South and equatorial Atlantic Ocean has been found to be related to a set of environmental parameters such as temperature, nutrient concentration, stratification and salinity. However, the direct influence of single parameters on the species is as yet unknown. In order to determine the effect of temperature on culture growth and cyst production, strains of the species were investigated in a temperature gradient box under controlled laboratory conditions.

Whereas culture growth was observed over a relatively broad range of 12.3–30.4°C in C. albatrosianum, 15.5–30.7°C in L. granifera, and 13.3–32.8°C in P. tuberosa, fossilisable cysts were mainly produced in a smaller range of 16.1–21.7°C in C. albatrosianum, 18.0–24.0°C in L. granifera and 22.3–27.6°C in P. tuberosa. By comparing laboratory and field data it is shown that a good correlation exists in P. tuberosa, whereas in C. albatrosianum and L. granifera higher temperatures of fossilisable cyst production were expected from the field data. As possible explanations different depths of vegetative reproduction and cyst production and seasonality in cyst production are discussed.

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