The structure of phytoplankton communities off Cape Juby (28°N) in the Canary Current System (Northwest Africa)

Phytoplankton community in the upwelling area of cape Juby was studied in two years 2009 and 2010. Diversity, abundance and taxonomic composition were characterized at 5 stations for each period. A total of 107 species have been recorded. Diatoms constituted the majority group represented by a total of 54 taxa, followed by dinoflagellates with 45 taxa, and 8 taxa belonging to other groups. The highest phytoplankton densities were recorded in February and June 2009, and the lowest at august 2010. The maximum number of species (87) was recorded during February 2009 while the minimum (22) was noted during August 2010. Shannon diversity index (H’) values varied in a range of 1,48 and 3,35 bits, generally in parallel with the species number (SR) and the eveness (J) variations. 34 taxa dominated the phytoplankton community but only 5 species were dominant commonly during the seven sampled periods. An overall high similarity on the species number (Sorensen Index q, Hierarchical clustering and NMDS analysis) was observed between the coast and the open ocean during all the sampling periods.