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Ocean life

Ocean floor life

Crinoids, sponges and sea squirtsCrinoids, sponges and sea squirts On the ocean floor, on average about 4500 metres (15,000 feet) below the surface, the water is completely black and very cold. Here in the abyssal zone animals cannot use sight to find their food, so many are blind. Instead, they have highly developed senses of touch, or are able to detect chemical changes in the water that will lead them to a food source. The weight of water above the plain is immense, so these animals must be specially adapted to live in such a high-pressure environment. Their bodies have no air spaces inside them.

Skeletons of microscopic animalsSkeletons of microscopic animals


The floor of the oceans is covered with a thick layer of ooze, made up of sand, mud and debris from plant and animal life that forms a constant rain from the waters above. Having taken millions of years to accumulate, the ooze may be about 500 metres (about 1600 feet) thick in places. Some animals burrow into the ooze or creep across it, feeding on any animal remains, including skeletons and droppings, they find there.


Living on the ooze

There is a surprisingly high diversity of life on the abyssal plain. At a single site scientists have estimated there to be, for example, about 500 species of marine invertebrate (worms, crustaceans, molluscs and worms).

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