Eine Höraufnahme über Korallenriffe, (Text s.u.) geeignet für den Regelstandard der Phase 7. From above, the ocean seems empty. Like a desert made of water it seems barren and uninhabited. But that is just on the surface. Let us explore the colours and life that exists on the coral reefs. Coral reefs are only found in shallow, tropical seas. They may look like colourful rocks or even plants. But coral really is an animal. Corals are built by polyps, which are very small creatures related to jellyfish. Unlike jellyfish, corals do not move. They grow together in a colony called coral head. A small piece of coral may be made of hundreds of polyps. A bigger one may have thousands! Corals grow slowly. Only a few centimeters per year. It can take hundreds of years to form large pieces. Some corals are hard, others are soft. They may look like fans, bushes or feathers. But no matter what they look like, corals are a colony of tiny animals living together. When many corals grow close together, it is called a reef. Reefs are a very important habitat for fish and other sea creatures. Algae and sponges grow in a reef, which in turn, provides food for a variety of creatures such as the sea turtle. Sea turtles rely on the food, which grows in the reef. And the reef, in turn, relies on the turtles. It is a partnership, that benefits both creatures. The sea turtles get a reliable source of food as they eat the algae and sponges off the reef. Without the sea turtles coming and eating these algae and sponges, the reef would be overgrown by them. Preventing the coral from growing and expanding. With lowered turtle population in oceans worldwide, the health of coral reef systems will suffer. It is important that we do our best to protect these peaceful reptiles. Coral reefs are sometimes called 'the rainforest of the sea'. They cover only a tiny area of the ocean, but provide for a quarter of ocean animals. Unfortunately, The coral reef ecosystem is a fragile one. The delicate balance between the coral, fish, algae and animals which live there, is easily disrupted. Overfishing by humans, ocean pollution and warming temperatures have all put the world's coral reefs at risk. Right now, more than half of the world's reef systems are in danger. If nothing changes, then within 15 years nearly all corals in the world will be in danger of dying and disappearing.