Humpback whales near the Hawaiian Islands
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Courtesy of NOAA

Life in the Open Ocean

The open ocean is the largest area of the marine ecosystem. It reaches from coasts to the middle of the ocean. The living things that survive in the open ocean need to have a way to float or swim in ocean water.†

At the top of the open ocean, sunlight shines through the water. This is where most life in the open ocean is found.

Some living things float or drift in ocean water. They are called plankton. They are moved around the open ocean by currents and wind.† Some plankton, like diatoms and other algae, do photosynthesis. They are the beginning of food chains. Other plankton are animals and one-celled protozoa that drift in the ocean water.

Many animals swim in the open ocean, including fish, whales, and sharks. Some fish swim in schools while others swim alone.† Some animals have other ways of moving through the water. Squid propel themselves through the ocean with a jet of water. Flying fish are able to glide just above the water surface using fins shaped like wings.

In the parts of the deep open ocean, too deep for sunlight to shine through, there are fish and other animals likegiant squid. Many animals living in the deep ocean get the food they need from the bodies of dead animals falling from the shallower water above.

Last modified June 1, 2010 by Lisa Gardiner.

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