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Jacques Giraudeau, John Rogers, Phytoplankton Biomass and Sea-Surface Temperature Estimates from Sea-Bed Distribution of Nannofossils and Planktonic Foraminifera in the Benguela Upwelling System, Micropaleontology, Vol. 40, No. 3 (Autumn, 1994), pp. 275-285
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Giraudeau et al. (1994) studied this question.
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