The Fateful Tale of Chesapeake Bay - Episode Two: The Seabed

In the second episode of this 4-part podcast, Miriam and Judith sink into the deeper waters of the Bay to explore the seabed, the marine life that it sustains and the fragile ecosystem of which it is a part.
What makes a deadzone? What is the seabed thinking? And what do trees have to do with any of this?