The Angola-Benguela Current system is one of the major upwelling regions of the world, intermediate in intensity between the systems off Peru and California. It is characterized by organic-rich sediments that provide an excellent record of productivity history, which in turn is closely related to regional dynamics of circulation, mixing, and upwelling (Wefer, Berger, Richter, et al., 1998).
The Benguela Current (BC) originates near the Cape of Good Hope. On its way northward and at ~28oS, the BC divides into an oceanic (Benguela Oceanic Current) and a coastal branch (Benguela Coastal Current [BCC]) (Stramma and Peterson, 1989). The cool and nutrient-rich upwelled waters of the BCC are fed from the thermocline underlying South Atlantic central water, which in turn originates at the subtropical-subantarctic front by mixing and sinking of subtropical and subantarctic surface water (Lutjeharms and Valentine, 1987).
The Benguela upwelling area can be divided into a true coastal upwelling regime, averaging ~150-200 km wide, that is composed of several distinct upwelling cells (Lutjeharms and Meeuwis, 1987) and a filamentous mixing domain streaming offshore, with filaments that may exceed 1000 km in length (Lutjeharms et al., 1991).
Site 1084 (25o30.8'S, 13o1.7'E; water depth 1991.9 m) lies close to the largest and most active coastal upwelling center, the Lüderitz cell. Upwelling in this area is characterized by year-round high primary production, and phytoplankton assemblages are generally dominated by diatoms (Shannon and Pillar, 1986).
Site 1082 (21o5.6'S, 11o49.2'E; water depth 1279.3 m) is located at a crucial latitude where the BC turns westward into the open ocean. Thus, the sediments from this site represent an important key for reconstructing the history of the BC.