"The Sargasso Sea occupies almost two thirds of the North Atlantic Ocean. Within this sea, circling ocean currents accumulate mats of Sargassum seaweed that shelter a surprising variety of fishes, snails, crabs, and other small animals. The animal community today is much less diverse than it was in the early 1970s, when the last detailed studies were completed in this region. This study shows that animal communities in the Sargasso Sea are definitely changing. The next step is to find out why."