Influence of Mesologic Parameters on the Phytoplankton Distribution along of Transects Localized Between Cape Cantin and Dakhla

The marine phytoplankton was studied in january and july 2002 in four transects: 32°30’n, 29°n, 24°30’n and24°n. water samples were collected at four depths (surface, 10m, 30m and 50m).the total microalgal densityshows that the southern area is more productive than the northern. the maximum of density is recorded at -30mdepth in winter and -10m in summer in all transects. the analysis of the spatiotemporal variation of thephysicochemical parameters shows an activity of upwelling during summer in whole transects, while in winterno marked gradient of physicochemical parameters was detected, except in dakhla (24°n), where a coldfilament was observed. generally, the upwelling activity, the presence of filaments and the morphology of thecoast determine largely the spatiotemporal variability of phytoplankton in the studied areas.