Upper Pleistocene Ethmodiscus rex Oozes from the Eastern Equatorial Atlantic

The large planktonic diatom Ethmodiscus rex (Rattray) Hendey occurs in largely monospecific oozes in the eastern equatorial Atlantic. These oozes are restricted to glacial episodes in Pleistocene sediments and are found only between the equator and latitude 5? N. The various mechanisms proposed over the past 70 years to account for these accumulations are reviewed and evaluated. We conclude that the Wiseman-Hendey theory of a massive, but short-lived, productivity bloom of E. rex is the most plausible and best fits the observed data. The causes of such a high production of one species are unknown. Upper Pleistocene Ethmodiscus rex oozes from the eastern equatorial Atlantic