Radiolaria in the surface layer of bottom sediments from the northern sector of the Benguela upwelling

The maximum abundance of Radiolaria (20000-40000 individuals per 1 g of sediment) was determined in sediments of the open ocean at depth 2000-4100 m. Species of tropical zones dominate in the assemblages; however content of species of subpolar and moderate zones reaches considerable values.

In shelf sediments at depth 60-160 m abundance of Radiolaria (up to 5000 ind./g) is greater than in sediments of the continental slope. In shelf assemblages species of subpolar and temperate zones dominate. A characteristic feature of the shelf upwelling assemblages of Radiolaria is expressed by predominance of Lithomelissa setosa (Joerg.) (up to 50-80% at 23-25°S).