A. G. Matul’
Shirshov Institute of Oceanology, Russian Academy of Sciences, Nakhimovskii pr. 36, Moscow, 117218 Russia
Received December 10, 1996; in final form, March 4, 1998
Abstract—Quantitative data on the radiolarian assemblages from the Benguela upwelling at 17°–25° S were
obtained from the analysis of 18 bottom sediment samples. The maximum absolute concentration of Radiolaria
(20 000–40 000 individuals per 1 g of sediment) was determined in the sediments of the open ocean at a depth
of 2000–4100 m. Species of tropical zones dominate in the assemblages; however, the content of species of sub-
polar and moderate zones reaches considerable values. In shelf sediments at a depth of 60–160 m, the absolute
concentration of Radiolaria (up to 5000 ind./g) is greater than in the sediments of the continental slope. In the
shelf assemblages, the species of subpolar and temperate zones dominate. The characteristic feature of the shelf
upwelling assemblages of Radiolaria is expressed by the predominance of Lithomelissa setosa (Joerg.) (up to
50–80% at 23°–25° S). L. setosa is a common representative of the radiolarian assemblages of the subpolar and
temperate regions of the World Ocean. It is presumably regarded as an eurybiont species. Probably, it propa-
gates with the subantarctic intermediate water masses from the circumantarctic area to the Benguela upwelling
region where there are favorable living conditions: the subsurface water temperature is no greater than 10°C
and there are abundant nutrients.
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