The French Atlantic Coasts

Summer mass blooms of macroalgae have been occurring increasingly for two decades along the French Atlantic coastline (Fig. 9.1). The coasts of Brittany are the most affected, considering the nearly 100 000 m3 of green seaweeds collected yearly from the beaches. One member of the genus Ulva is particularly involved in these mass blooms, although some ectocarpales, for example Pilayella littoralis, recently appeared in some localities.