TROPHIC RELATIONSHIPS BETWEEN PELAGIC COMPONENTS OF A MESOSCALE FRONT- THE RHONE RIVER PLUME FRONT ECOSYSTEM

The Rhone River plume front is a mesoscale spatial and temporal ecosys tem, in which density and nutrient salts gradients extend from a few c entimetres to a few kilometres and the lifetime of the hydrodynamical structure lasts from a few hours to a few days. In such spatial and te mporal conditions, only the productive components (phytoplankton and b acteria) of the pelagic ecosystem are able to adjust to these rapid va riations. The coupling of this production with exporters (zooplankton and flagellates) could not be demonstrated. The biological events of t his mesoscale front are mainly ruled by physical processes.