More than two-thirds of the Earth’s surface is covered by the oceans. The oceans are home to a wide variety of life, from microscopic plants to giant whales. Most ocean creatures, however, live in shallow waters near the coast, particularly on the sea bed. In the rest of the ocean, especially below a depth of about 1000 metres (3300 feet) where it is always cold and dark, there are very few living things to be found.

Surface waters

The richest variety of life in the oceans is found near the water’s surface. Here, sunlight allows microscopic plants, called plankton, to live. The plankton float in surface waters. They are eaten by tiny animals, another kind of plankton, that drift in the ocean currents. These include fish larvae (baby fish that have just hatched out). Fish and squid feed on them.

Coral reefs

Coral reefs are found in warm shallow waters in tropical regions. They grow around volcanic islands or close to rocky coastlines. They are made from the layers of skeletons of tiny animals called coral polyps. Over many years, colonies of polyps build up great banks of coral, known as reefs. There are many different kinds of coral. Their bright colours make a coral reef look like an undersea garden.

Deepwater life

Deep below the surface of the oceans, the water is dark and cold. Some very weird-looking creatures live here. The gulper fish has huge jaws and a stretchy stomach. This allows it to eat fish much larger than itself.