Hydrological and biological variability in the Gulf of Lions. II. Productivity on the inner edge of the North Mediterranean Current.

An estimation of the annual productivity in the Gulf of Lions has been made in the 0-100 m layer using a Let-Go system, with monthly measurements at a fixed station. A value of 140 to 150 g m(-2) a(-1) of C is found, of which around 75 % occurs in the upper 50 m. The seasonal production is described according to three distinct patterns during the two hydrological seasons: (1) variable production in winter; (2) surface bloom in late winter; (3) homogeneous and mean production in summer with a clear Deep Chlorophyll Maximum. The hydrological winter phase represented 60 % of total annual production. The seasonal duality of the hydrodynamic system and the mesoscale variations of the Northern Mediterranean Current account for the variability and the evolution of the three production patterns. (C) Elsevier, Paris.