Seasonal and inter-annual variability of the chlorophyll concentration in the coastal area of Gulf of Guinea using SeaWIFS images

Seasonal and inter-annual chlorophyll variability in the Gulf of Guinea is analysed for the period 1997-2004 using SeaWiFS and sea surface temperature images. Results show that the Gulf of Guinea coastal zone is characterized by a large spatial and temporal variability of its physical and biological properties. The coastal regions of Guinea-Bissau and Côte d'Ivoire and to a lesser extent Ghana are the only ones showing typical behaviour linking coastal upwellings to higher chlorophyll concentrations. The Liberian coastal zone is characterized by an almost nil inter-annual variability while the Nigerian and Gabonese coastal zones show no relation between chlorophyll and temperature. Many physical processes appear to play an important role in regions' biological responses, such as the Inter-Tropical Convergence Zone, which considerably modifies wind patterns throughout the Gulf of Guinea, and the Atlantic El-Niño, which modifies water masses in the easternequatorial region. © 2011 Pierre Larouche for the Department of Fisheries and Oceans.