In-situ particle sizing at sea bottom interface

Particle size discrimination has been becoming practically available for direct underwater suspended matter quantification. At the bottom sediment water interface, it is particularly important to make relevant characterization of the sediment transport process in order to get good correlations between erosion and environmental stresses such as current or wind effects. The paper presents some experiments carried out in the laboratory with different specific calibrated particles distributed inside the size range limits of the instrument (1-400 pm). After a description of the equipment and the experimental set up, some emphasis is put on the capability to sense hydrodynamic effects like elutriation in more or less turbulent conditions. In a second phase, some results obtained with stimulated bottom current provided in a test sea-water tank are proposed and discussed. This nearly real condition has been achieved on different types of seabed sediment such as sands or estuary silts