REVIEW OF GROSS COMMUNITY PRODUCTION, PRIMARY PRODUCTION, NET COMMUNITY PRODUCTION AND DARK COMMUNITY RESPIRATION IN THE GULF-OF-LIONS

Thirty years of data were used to examine the influence of the Rhone R iver discharge on the spatio-temporal distribution of primary producti on in the Gulf of Lions. These patterns are characterised for four hyd rological provinces: (i) the Gulf of Marseilles, a coastal oligotrophi c system exhibiting a typical diatom-based bloom succession; (ii) the mouth and plume of the Rhone River, containing high levels of nutrient s, constant levels of chlorophyll a, and a plankton assemblage dominat ed by nanoflagellates; (iii) the highly productive dilution area to th e west of the Rhone, with a diatom spring bloom and smaller winter dia tom blooms; (iv) the southern area encompassing the oligotrophic Ligur o-Provencal Current, a frontal zone of constantly high primary product ion and a divergence area exhibiting a typical spring bloom situation. No evidence of eutrophication due to river input was seen. In situ an d in vitro net community production data suggest the Gulf of Lions as a whole is a balanced ecosystem on an annual time scale, with the mean primary production lying between 78 and 142 g C m(-2) a(-1). (C) 1997 Elsevier Science Ltd.