05/23/13 - Thursday's Topical Currents begins . . . underwater. Many are unaware, but the crystal-clear seawater below the Keys is the third-largest barrier reef in the world. It has a vast history, as well. Many enjoy scuba or snorkel, but historically, the reef has been a bane to shipping . . . and pirates. We speak with Brad Bertelli, author of “Snorkeling the Florida Keys." And more, Linda Gassenheimer’s Food & Dining with wine columnist Fred Tasker. That’s Topical Currents Thursday at 1pm on WLRN-HD1 rebroadcast at 7pm on WLRN-HD2 and audio on-demand after the live program.