1001 Space Earth Earth Rocks and Minerals Landscape Sea Weather and Climate Natural Disasters Resources Nature History Human World Science and Technology

Choose a Page:How long has there been life in th...How much of the Earth is covered b...Why does seawater taste salty?Is the ocean floor flat?What causes waves?What is an iceberg?Are tidal waves caused by the tides?What are ocean currents?How has the ocean bed been measured?How does the sea affect the climate?*How do coral reefs form?*Are there currents at great depths?Why does the tide come in and go out? How do coral reefs form? A coral is a small animal that lives all its life in one place. It thrives in warm, shallow seawater. The coral builds a shell, which it cements onto the dead shells of other corals, and so a great mass of rocky shell material is built up. If the sea bed sinks, the corals continue to grow upward, forming a reef. Many sinking islands in the Pacific Ocean have disappeared, leaving only a coral reef behind. Australia's Great Barrier Reef is the largest coral reef in the World.   Previous: Back Book: 1001 Section: Earth Chapter: Sea