Possible upwelling phenomenon off the Nigerian coast

Abstract

Published information favour the occurrence in certain years of wind related upwelling in Nigeria's inshore waters especially between July and September. This is corroborated by the prevalence of petroleum source beds, glauconite, phosphorite and periodic abundance of some fish including Engraulis encrassicolus, Sardinella maderensis and the bonga Ethalmosa fimbriata which are pelagic and are associated with upwelling phenomena. Examination of temperature and salinity data for 1978 - 81 suggested that upwelling occurred during certain periods of each year. However, wind data for the same period lacked details to support postulates of wind driven upwelling. Instead, dynamic upwelling resulting from the juxtaposition of the currents in the area is adduced. This was probably augmented by transitory wind driven upwelling. A minor upwelling between December and February proposed by previous workers, though not apparent from this study, could emanate from channeled flow of off-shore winds.