SEDIMENTATION-RATE AND EARLY DIAGENESIS OF PARTICULATE ORGANIC NITROGEN AND CARBON IN AYDAT LAKE (PUY-DE-DOME, FRANCE)

A core of low-compacted sediment from a eutrophic lake (Aydat Lake) was extracted in order to study the early diagenesis of particulate organic carbon and nitrogen. We use a simple model where the advection rate was estimated with the classical Pb-210 method. We show that the Pb-210 data are not sufficient by themselves to provide a correct estimation of this parameter, but a model which includes the sediment compaction leads to a better understanding of the sedimentation process. Compaction is also taken into account in the diagenetic model which allows us to make an estimation of the carbon and nitrogen mineralization rates.