| Investigation of Dispersal Mechanisms of Zoo- and Ichthyoplankton in the Region of the Angola-Benguela Front |
Acronym: BENEFIT
Period: January 1999 till December 2003
Status: Completed
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| Institute |
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- Center for Tropical Marine Ecology, more, co-ordinator
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| Abstract |
| The Benguela Current ecosystem off south-west Africa is one of four major eastern boundary current systems of the world?s oceans. Eastern boundary current systems are characterized by coastal upwelling of deep, nutrient-rich water onto the continental shelf as a result of equatorward wind stress. They are areas of high productivity supporting abundant valuable fisheries resources. The Benguela Current region extends from the south-western tip of South Africa northward along the Namibian coast into southern Angola, roughly between about 14 and 37°S. The northern boundary is the Angola-Benguela Front, a permanent feature at the surface. Both, the northly flowing Benguela and the southly flowing Angola current meet in this area and turn towards the open southern Ocean producing a permanent convergent zone, the Angola-Benguela Front. This warm-water boundary also moves during the year.These hydrographical conditions are likely to have considerable impacts on the distribution of planktonic populations, including zooplankton and ichthyoplankton, which are subjected to the movement of water masses associated with the circulation of the region, transporting them offshore into areas unfavourable to their population dynamics, and the crossing of hydrographical fronts should be impossible for them. However, we learn from the distribution pattern of many plankton organisms, that they must be able to overcome these constraints by vertical migration, usage of counter currents etc. to remain in their preferred habitats and also cross hydrographical fronts. This project seeks at exploring mechanisms and adaptive strategies adopted by zoo- and ichthyoplankton populations which ensure their retention within the Benguela system. In addition we are looking for adaptations in feeding ecology and physiology of zooplankton organisms to understand the top-down or bottom-up interaction between different trophic levels and explain seasonal and spatial patterns of abundance and distribution species relevant to the fisheries. |
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