Resumen de Bathyal benthonic foraminifera biofacies from the Nigeria sector of the Gulf of Guinea (West Africa)
Forty deep water (bathyal) marine, bottom, van Veen grab samples collected during the marine sedimentological survey of the offshore Niger delta, by the M. V. Mees Cremer expedition (1959), were studied for their total benthonic foraminifera content. Benthonic foraminifera compared to the planktonic forms are few within this environment, the foraminiferal assemblage being dominated almost exclusively by planktonic forms. Many of the benthonic foraminifera appear to be restricted in their distribution, according to depth, to allow the subdivisions of the bathyal environment. Bottom sediments have been studied in the hope that additional information, would further be obtained on patterns of distribution. Probably due to uniform temperature and salinity, some of the benthonic species are ubiquitous. Canyon samples contain admixed fauna (littoral and bathyal). The mixing being considered the result of hydrodynamic conditions, such as mudslides or turbidity currents. Variation in size, form and ornamentation, related to water depths have been noticed and are considered, due, probably, to minor changes in temperature with depth. Four distinct bathyal biofacies Upper, Middle, Upper Lower and Lower Lower are recognised, based on relative abundance and depths of first and last appearance. Some of the benthonic species are restricted to each of the bathyal biofacies
