Material property distributions on continental shelves result from the mixing and modifications of estuarine and deep-ocean source waters. How this occurs depends on the momentum and buoyancy that are input either locally on the shelf or from the deep-ocean at the shelf break. We address this question of local versus deep-ocean forcing for the West Florida Shelf (WFS) using in situ data and a numerical circulation model. The spring and summer seasons of 1998 and 1999 show distinctively different water properties on the shelf and at the shelf break. We account for these differences by a combination of local forcing, independent of the adjacent Gulf of Mexico Loop Current, and interactions of the Loop Current with the shelf. The primary role of the deep ocean is to set the height of material isopleths along the shelf slope. Whether or not these material isopleths broach the shelf break is then a consequence of local, shelf-wide wind and buoyancy forcing. The subsequent along- and across-shelf distributions are accomplished through a combination of local and deep-ocean effects, with the bottom Ekman layer being the major conduit for the across-shelf transport of ecologically important materials.