Nearbed Flows and Sediment Movement on the Continental Slope

The steep continental slopes of the southern Celtic shelf have long been thought to be a major export region for the flux of sediment from the south west approaches to the deep ocean (47-49^). Recent studies have suggested that the transfer of energy from the large barotropic tidal currents to internal tides, and higher frequency internal waves is locally enhanced, and provides a mechanism for the re-suspension and down-slope transport of bed material on the upper slope region. This material is thought to be preferentially transported at the head of the many submarine canyons that exist along these ocean margins, where the barotropic tidal currents are locally amplified and internal wave energy focused. A unique 23 day deployment of the benlhic lander STABLE (Sediment Transport and Boundary Layer Equipment) in July 1990, was at a depth of 388m on La Chapelle Bank continental slope. The site was at the head of a canyon, and at a depth thought to be critical for the generation of internal tidal energy. It was also at the deep water end of a transect of two current meter moorings across the slope. These measurement