Chitin biomass in marine sediments

One hundred marine sediments of various origins were screened in order to evaluate their chitin biomass. Our purpose was to assess the detritic chitin stocks in order to find some potential new source of chitin. The chitin biomass of marine sediments is very diversified, from 2 up to 2800 ug g-1 decalcified sediment (DS). Most sediments have low or very low chitin biomass (67% under 100 ug g-1 DS). No significant difference relmated to depth nor climatic influence was found except that all sediments richer in chitin (above 300 ug g-1 DS) are on the continental shelf (above 200m dephth). Actually, the chitin content is highter in coarse, much calcified sediments of organoclastic origin ; bryozoa and shelly sands and gravels are the richest. The powerful hydrolytic activity of microorganisms lower the steady state equilibrium level between chitin input and weathering, so most "unprotected" chitin is weathered very soon after settling. Marine sediments appears thus as a non comprtitive potential industrial chitin source.