KINGSTON, Jamaica (AP) — The picture-perfect beaches and turquoise waters that people expect on their visits to the Caribbean are increasingly being fouled by mats of decaying seaweed that attract biting sand fleas and smell like rotten eggs.Clumps of the brownish seaweed known as sargassum have long washed up on Caribbean coastlines, but researchers say the algae blooms have exploded in extent and frequency in recent years.