Multi-table approach to assess the biogeography of phytoplankton: ecological and management implications

This study aimed to determine whether temporal variation of Bacillariophyceae and Dinophyceae changed spatially, to examine which bio-geographical features determined the spatial structure of Bacillariophyceae/Dinophyceae assemblages, and to compare between-zones variations in the phytoplankton taxonomic composition. The study is based on dataset collected during the period 2004–2007 along the coastal zones of the Gulf of Gabès using the STATIS multi-table method. This method allowed a measure of similarity between 15 sampling zones, the visualization of the species assemblages showing similar spatial variations and the reproducibility of this pattern for each zones’ association. High spatial gradient was evident for most species, and three large regions were obtained. Thirteen different taxa assemblages were then detected performing a common pattern of phytoplankton composition. For each assemblage, the most representative region which encompasses groups of zones with similar properties was identified. The hydrodynamic processes and geomorphologic properties of the different areas as well as anthropogenic activities are incriminated to play a major role in shaping the structural patterns of phytoplankton along the coastal zones of the Gulf of Gabès. This study suggested considering the bio-geographical features in the assessment of phytoplankton spatial assemblage.