Although they occupy less than one quarter of one percent of Earth's marine environments, coral reefs are home to more than 25 percent of all known marine species. These habitats have been called the "rainforests of the sea," both because they support an abundance of species, and because they are predominantly located in regions of the globe with high human population growth rates. Reefs are also particularly vulnerable to exploitation, as are most rainforests. In this video segment from ZOOM, a Florida girl explores the warm shallow waters off the coral island on which she lives.