Abundance of organic-walled dinoflagellate cysts of sediment core GeoB3603-2

• Main Authors: Esper, Oliver, Versteegh, Gerard J M, Zonneveld, Karin A F, Willems, Helmut
• Format: Dataset
• Language: English
• Published: PANGAEA 2004
• Subjects: Bitectatodinium spongium; Bitectatodinium tepikiense; Brigantedinium; Brigantedinium cariacoense; Brigantedinium simplex; Counting; palynology; Dalella chathamensis; DEPTH; sediment/rock; Dinoflagellate cyst indeterminata; Dinoflagellate cyst reworked; Echinidinium aculeatum; Echinidinium delicatum; Echinidinium granulatum; Echinidinium spp.; Echinidinium transparantum; GeoB; GeoB3603-2; Geosciences; University of Bremen; Gravity corer (Kiel type); Impagidinium aculeatum; Impagidinium pallidum; Impagidinium paradoxum; Impagidinium patulum; Impagidinium plicatum; Impagidinium sp.; Impagidinium sphaericum; Impagidinium strialatum; Impagidinium variaseptum; Impagidinium velorum; Lingulodinium machaerophorum long; M34/1; Meteor (1986); Multispinula quanta; Nematosphaeropsis labyrinthus; Operculodinium israelianum long; Operculodinium israelianum short; Operculodinium janduchenei; Pentapharsodinium dalei; Pollen; taeniate; bisaccate indeterminata; total; Polykrikos kofoidii; Polyspaeridium zoharyi; Protoceratium reticulatum long; Protoceratium reticulatum short; Antarctic; Indian; The Antarctic; Antarc*; South Atlantic Ocean
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.58937; https://doi.org/10.1594/PANGAEA.58937

Here, we reconstruct the varying influence of the Agulhas Current (AgC), the South Atlantic Current and the Antarctic Circumpolar Current on the Agulhas Retroflection (AgR) in the eastern South Atlantic Ocean for the last 160,000 years on the basis of the dinoflagellate cysts, pollen and spores present in a sediment core (GeoB 3603-2) from the southeastern Cape Basin offshore South Africa, where the Agulhas Current enters the Atlantic Ocean. Our analyses reveal strong orbital forcing on the heat exchange between the Indian Ocean and the South Atlantic Ocean during the Late Quaternary. Maxima in local productivity appear to be primarily related to a strengthening of the ocean circulation as a result of the high seasonal contrast during precession maxima. During precession minima, seasonal contrast was low and stratified, oligo- to mesotrophic conditions prevailed, notably when these minima coincided with the glacial terminations. The clear presence of periodicities on a sub-Milankovitch scale as well as modulations of the primary frequencies demonstrate that the Agulhas Retroflection furthermore is modulated substantially by complex interactions between the subtropical, 'precession-driven', climate and ocean circulation systems, and the southern, 'obliquity-driven', high latitudes.