Neutral carbohydrate geochemistry of particulate material (trap and core sediments) in an eutrophic lake (Aydat, France)

Carbohydrate compositions were determined on sinking particles and core samples from eutrophic lake Aydat. Carbohydrate fluxes indicate that phytoplanktonic production is the main organic matter (OM) source whereas the monosaccharides concentrations normalised to OC contents (T ) mostly reflect degradation. The abundance of rhamnose in all samples, its increasing fluxes (together with fucose) with increasing water depth, and its strong decrease in the top 5 cm of the bottom sediments mark the intense activity of the microbiota. The almost complete removal of sugars in the water and top sediment indicates very little contribution to the preserved OM stock.