"The world's oceans and seas cover about 71 percent of the Earth's surface, and make up by far the largest biome on the planet. A huge variety of animals and plants live in the warm, shallow waters of the continental shelves. Oceans and the life they contain are vital to human existence, yet today this biome is threatened by pollution, overfishing, and the rising levels of carbon dioxide being released into the atmosphere by human activity"--Back cover.