Billions of dollars and the fate of the Chesapeake Bay hinge on a set of computer simulations. Who are the scientists behind these "models," and how are their efforts being used to drive the biggest plan to clean up a body of water in U.S. history? Lewis Linker is one of the researchers at the heart of this project. He's the modeling coordinator for the Chesapeake Bay Program, a partnership between state and federal agencies tasked with protecting the nation's largest estuary. With his colleagues in Annapolis, Linker builds computer models to diagnose the Chesapeake's illnesses and investigate new cures. These models seek to represent the Bay's physics, chemistry, and biology using a series of mathematical calculations and some approximations. That's no small task.   more . . .