Reconstruction of palaeoceanographic conditions in the South Atlantic Ocean at the last two Terminations based on calcareous dinoflagellate cysts

Despite the increasing interest in the South Atlantic Ocean as a key area o f the heat exchange between the southern and the northern hemisphere, infor mation about its palaeoceanographic conditions during transitions from glac ial to interglacial stages, the so-called Terminations, are not well unders tood. Herein we attempt to increase this information by studying the calcar eous dinoflagellate cysts and the shells of Thoracosphaera heimii (calcareo us cysts) of five Late Quaternary South Atlantic Ocean cores. Extremely hig h accumulation rates of calcareous cysts at the Terminations might be due t o a combined effect of increased cyst production and better preservation as result of calm, oligotrophic conditions in the upper water layers. Low rel ative abundance of Sphaerodinella albatrosiana compared with Sphaerodinella tuberosa in the Cape Basin may be the result of the relatively colder envi ronmental conditions in this region compared with the equatorial Atlantic O cean with high relative abundance of S. albatrosiana. Furthermore, the pred ominance of S. tuberosa during glacials and interglacials at the observed s ite of the western Atlantic Ocean reflects decreased salinity in the upper water layer.