PARTICLE FLUXES OVER A MEDITERRANEAN SEAGRASS BED - A ONE-YEAR CASE-STUDY

A sediment trap experiment was carried out in the Bay of Calvi (Corsic a, France) over a Posidonia oceanica seagrass bed, at a depth of 36 m. The traps collected 44 samples over a complete annual cycle and allow ed a rough partition between 'sinking' and 'resuspended' matter. The m easured annual flux of particulate matter amounted to 1.3 kg m(-2), of which about 70% arose from sediment resuspension, this process being particularly enhanced during northerly gales. Resuspended material con sisted mainly of seagrass-derived detritus, as evidenced by SEM photom icrographs. Chemical analyses of trapped material showed seasonal vari ations in inorganic carbon content, organic C/N ratio and delta(13)C. Benthic signature (C-inorg, C-org- and C-13-enriched Posidonia-derived matter) was emphasized when resuspension occurred, while planktonic f eatures (N- and C-12-enriched matter) prevailed during bloom condition s.