AGGREGATE STUDIES IN THE BENTHIC BOUNDARY-LAYER AT A CONTINENTAL-MARGIN

A new instrument for aggregate size determinations in the benthic boun dary layer is described. It takes video pictures from the horizontal a ggregate flux at 10 to 100 cm above sea floor. For retrieving water sa mples at the depth of the video pictures, the system can be integrated into an existing bottom water sampler, the BIOPROBE system or work as an independent camera/sampling module in free fall lander systems at a maximum depth of 6000 m. A computer-based image analysis system is u sed to convert video film material to quantitative particle size and m orphology data. Deployments in the Greenland Sea continental margin do wn to 2800 m gave encouraging results. An analysis of horizontal aggre gate flow at 60 cm above sea floor is presented. The aggregate size di stribution was different due to varying particle characteristics of th e water and boundary layer flow conditions.