Preliminary results on chitin biomass in some benthic marine biocenoses

In an attempt to compare chitin productivity in different biocenoses from an ecological point of view, chitin biomass of some benthic communities was measured on Corsica northwest coasts (Calvi, Mediterranean Sea). In the infralittoral communities of photophilous algae characterized by Cystoseira stricta or C. crinita, the chitin biomass (excluding Decapod Crustaceans) was found relatively constant and amounted from 300 to 1100 mg chitin. m-2 (average 717 mg chitine. m-2 +/- 280) mainly due to exoskeletons of epiphytic encrusting organisms, such as bryozoans. Chitin biomass of Decapod Crustaceans was far more variable. Sciaphilous communities of semi-darked caves, dominated by sponges, had a lower chitin biomass, amounted from 130 to 370 mg chitin.m-2 (average 268 mg.m-2 +/- 106). Depth, from 5 to 35 meters, and slope did not seem to affect chitin biomass values.