SBI is a multi-year, multi-disciplinary program sponsored jointly by the National Science Foundation’s Office of Polar Programs and the High-latitude branch of the Office of Naval Research. The overall goal is to understand how the Arctic shelves communicate with the interior basin from a coupled physical--biogeochemical standpoint. The premise is that this system is in a delicate balance that could be upset by global change, which in turn could have important ramifications. These include possible melting of portions of the polar ice cover, changes in export of water to the global ocean, and alteration of the food web with significant consequences for native populations. From the physical oceanographic perspective the goal is straightforward: understand how shelf water is transferred, at the continental shelfbreak, to the interior basin in order to help maintain the “cold halocline” of the Arctic Ocean. This is the salty layer at mid-depth which shields the surface ice cover from the warm deep water. If this shield is weakened, there is more than enough heat contained in the underlying Atlantic-origin water to start melting the ice from below.