Reconstruction of recent and late Quaternary surface water masses of the western subtropical Atlantic Ocean based on calcareous and organic-walled dinoflagellate cysts.

Only very few studies focus on recent calcareous and organic-walled dinoflagellate cyst diversity, geographic distribution and ecology in the tropics, so that information on the distribution patterns and environmental affinities of individual cyst species is still extremely limited. This information is, however, essential if we want to use dinoflagellate cysts for palaeoenvironmental and -oceanographic reconstruction in tropical areas, and a large part of this thesis is devoted to the acquisition of such data. Surface sediment samples from the generally oligotrophic western equatorial Atlantic Ocean, an area greatly influeneed by Amazon River discharge waters, were quantitatively and statistically analysed for their total dinoflagellate cyst content. The surface water and thermocline conditions appear to be particularly suitable for high production rates of calcareous dinoflagellate cysts, especially in the oceanic regions beyond the far-reaching influenee of the Amazon River.