Les glucides et l'évolution de la matière organique dans les sédiments marins

Carbohydrates have been analysed in arder to establish the state of organic matter in sediment. Samples were collected bath in neritic and oceanic (Orgon croises) areas. Reported data demonstrate that the insoluble-carbohydratesfsoluble-carbohydrates ratio (1/S) is a good indicator of organic matter evolution. In sediments, 1/S values ranging from 6 to 8 are associated with slightly-degraded organic matter, whereas values higher than 10 and eyen up to 30 relate to highly-degraded material. Furthermore, 1/S and CjN ratios generally show the same profile in sediments. The balance betweeh soluble (S) and insoluble (1) carbohydrates depends on the early stages of organic matter evolution, the soluble fraction being more easily degraded; such factors as sedimentation rates, redox potential, or&anic matter origin, etc., have an influence on 1/S values. The increase of the 1/S ratio in sediments is also related to "stabilization" processes during burial.