Special Lecture
The fate of fluid and other particles in ocean flows can be determined by mapping out appropriate invariant manifolds in physical space. An example involving inertia induced settling that is solved by geometric singular perturbation theory will be discussed first. The adaptation of these geometric techniques to complex time-dependent flows will be outlined. These ideas will be applied to a numerical model involving circulation around an island in which the effects of chaotic advection associated with the dead zone are compared to the leakage due to Ekmann pumping.