I first heard about coral bleaching from Billy Causey, the manager of the Florida Keys National Marine Sanctuary. We were sitting in his office deep in a 67-acre hardwood hammock on Marathon Key. It is a place where ospreys, egrets, cormorants, fat black snakes, hermit crabs, parrot fish, even an old tropical fish collector like Billy can still find refuge from the Kmart mall sprawl out on Route 1. Thickset with iron-gray hair and sea-gray eyes, Causey, who moved to the Keys in 1973, sounds like some Old Testament Jeremiah as he recalls the gradual decline of the reef during the years he’s been here.