They are an ancient species of flowering plants that grow submerged in all of the world's oceans. Seagrasses link offshore coral reefs with coastal mangrove forests. Today, these "prairies of the sea," along with mangroves, are on the decline globally. Scientists fear the diminishing vegetation could result in an ecosystem collapse from the bottom of the food chain all the way to the top. Changing Seas joins experts in the field as they work to restore Florida's important mangroves and seagrasses.