Radiolarian and sedimentological studies on Neogene sediments of the Benguela Upwelling System

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We propose a 3 year study of the Benguela upwelling system... The Benguela upwelling system is one of the largest such in the global ocean. Upwelling is important to local fisheries, affects the regional climate of Africa and, via export of carbon to the sediments, the global C02 cycle. Previous DSDP and ODP drilling has recovered a detailed record of this system going back to the early late Miocene. Perhaps the most significant outcome of previous studies of this record is evidence that opal (Si02) and carbonate shelled phytoplankton records of productivity are frequently out of phase with each other. It is still not fully clear if this reflects true differences in how each phytoplankton group behaves over time, or if it is at least in part an artifact, due to difficulties in interpreting proxy indicators of past productivity. Because opal shelled and carbonate shelled phytoplankton export different ratios of nutrients - particularly carbon - these differences are of general importance in understanding the role of ocean productivity in regulating the global carbon cycle. Our goals are to better understand the extent and causes of decoupling between reserved records of biogenic silica based productivity ... and other components of productivity, and how these different components have evolved over the last 10 my in the Benguela upwelling system...