Late Quaternary history of the Agulhas Current


  • Amos Winter,

  • Keith Martin


The Agulhas Current, located in the South West Indian Ocean, is one of the world's major western-boundary currents. Vertical and lateral shifts in the Current's movements, especially during glacial intervals, would effect inter- and intra-ocean heat transfers and thus affect the world's climate, particularly off southern Africa. Oxygen isotope ratios of two cores recovered from beneath the Agulhas Current record isotopic shifts probably induced by ice volume effects with little additional shift related to temperature changes, suggesting that temperature and mean position of the flow has been stable for at least 150,000 years. Changes in the percent abundances of coccolithophore species from the same cores suggest changes in paleoproductivity due to eddy formation, lowering of sea level or nutrient content from land sources. Absence of any cold water microfossils at our southern core location suggests that during the Last Glacial, the Agulhas Current probably transferred heat from low to high latitudes and probably reached as far south as 38°S before retroflecting close to its modern-day position.