I moved to paradise: Cozumel, the beautiful island in the Mexican Caribbean. Like the rest of the Riviera Maya, its warm, clear water called to me like a siren song. Then came sargassum. That, in itself, is not unusual. Sargassum is part of life in this region. But over the past eight years living on Cozumel, I’ve noticed a change: every year, there seems to be more of it. Much more. When sargassu...