Remises en suspension sédimentaires observées en Méditerranée par 2 000 m de profondeur à l'aide de pièces à particules
Four sediment traps of two different types and two current meters were deployed fixed to two identical moorings, at a depth of 2 000 m, off the coast at Nice, for 70 days between April and June 1987. The particulate flux measured with sediment traps decreased from 1 000 to 95 mg/m2/day during this experiment. The carbonate carbon concentration of the particles also decreased during this period; organic carbon concentrations varied inversely with the flux, increasing from 1.8 to 3.7 % of the particle dry weight. It is concluded that these changes reveal the presence of a deep-sea storm with a significant resuspension of sediment to a height greater than 200 m (distance of the traps from the bottom). By the end of the experiment, identical sediment traps had not collected the same particle weight although the distance between them was only 300 m. This flux variation indicates the high horizontal heterogeneity of the resuspension. The study confirms that continental slopes are the centre of sedimentary events which, although sporadic, are of great intensity, displacing large masses of particulate material over considerable distances.