Seasonal and interannual patterns of chlorophyll bloom timing in the Gulf of Cadiz

Seasonal and interannual variability of the spring bloom in the Gulf of Cadiz, western North Atlantic, has been investigated using remote sensing chlorophyll-a (chl-a) concentration between 1997 and 2007. Variability in both the timing and magnitude of the spring bloom in the basin has been evaluated according to physical properties in the water column such as mixed layer depth (MLD), sea surface temperature (SST), sea level anomaly (SLA), absolute dynamic topography (ADT) and wind forcing. The analysis indicated that the timing, size and duration of the phytoplankton bloom in this zone is influenced by meteorological and oceanographic conditions, which means that it can vary widely from one year to another. These results in conjunction with previous studies performed in the area show that the timing of the spring bloom affects markedly the development of zooplankton, the survival of juvenile fish and the seasonality of the biological carbon pump in the Gulf of Cadiz.