You can’t see them on the surface. But at the bottom of some of the world’s largest bodies of water are areas called dead zones where fish and other life can’t survive. Robert Diaz (College of William & Mary) tracks the development of these dead zones, which are rapidly increasing. He says agricultural runoff and pollution are the cause, but that it’s not too late to repair the damage. Also featured: Twenty years ago, the sport of fly-fishing experienced a renaissance when the film A River Runs Through It was released. Today, it’s still a popular sport. But angling for trout is a complex matter. Stan Ulanski (James Madison University), author of The Science of Fly-Fishing, says an understanding of science can enhance an angler’s experience.