Purpose of Activity
Using a physical simulation, we explore the vertical density structure within the ocean and how layering (density stratification) controls water motion, impedes nutrient transport, and regulates biological productivity. Our demonstration enables students to visualize the formation of horizontal layers in the ocean’s interior and the slow undulation of large-amplitude internal waves. We show that stratification limits the vertical transport of energy and nutrients. The region of strong vertical density gradient—the pycnocline—is a barrier to the downward propagation of wind energy as well as the upward transport of nutrients into the euphotic zone.