Trophic regimes of the Red Sea: a satellite analysis

Until now, in situ sampling of the Red Sea remains a challenge. Portioning of the red sea using cluster method based on satellite surface chlorophyll concentration could help to identify homogeneous bio-regions and guide for in situ sampling. Thus, ten years of satellite surface chlorophyll concentration observations, presently available, were used to characterize the biogeography of the Red Sea and the resulting seasonal cycle of phytoplankton for each bioregions. A K-means cluster analysis has been applied on the satellite time-series of chlorophyll concentration. We found 5 significant bio-regions based on climatological seasonality (phenology) of the phytoplankton. These 5 bio-regions are linked to the biophysical-interactions observed in this environment. For example, the northern region is characterized by a clear phytoplankton bloom resulting from mixing events in the winter. On the other hand, the most southern bio-region is characterized by a phytoplankton bloom in summer due to an intrusion of nutrient-rich water through the Gulf of Aden in response to the monsoon. The resulting coherent patterns for each bio-regions need to be explained based on the knowledge of the basin’s functioning and modeling.