Oceans are large bodies of saltwater. They cover 71 percent of Earth’s surface. The oceans contain 97 percent of all the water on Earth.
The Five Oceans
Earth has five oceans. The largest is the Pacific Ocean. The smallest is the Arctic Ocean. The other oceans are the Atlantic Ocean, the Indian Ocean, and the Southern Ocean.
The Pacific Ocean is located between North and South America and Asia. It covers about 60 million square miles (155 million square kilometers). This area is 30 percent of Earth’s surface.
The Arctic Ocean is located above the Arctic Circle. It covers about 5 million square miles (13 million square kilometers).
The Atlantic Ocean is located between North and South America and Europe and Africa. It covers about 30 million square miles (78 million square kilometers).
The Indian Ocean is located between Africa and Australia. It covers 26 million square miles (67 million square kilometers).
The Southern Ocean surrounds Antarctica. It covers 8 million square miles (21 million square kilometers).
The average depth of the oceans is about 12,100 feet (3,688 meters). The deepest spot is the Mariana Trench in the Pacific Ocean. It is about 35,750 feet (10,897 meters) deep.
Oceans and the Weather
Oceans help regulate Earth’s weather. In summer, the oceans absorb heat from the sun. In winter, the oceans release this heat into the air.
When the sun heats the oceans’ surface, water evaporates. It turns into vapor and rises into the air. The vapor then forms clouds.
When these clouds cool off, they release rain. Almost all of the rain that falls on Earth comes from the oceans.
Ocean water moves in patterns called currents. Some currents carry warm water from the equator toward the North Pole or the South Pole. (The equator is an imaginary line that circles Earth halfway between the North Pole and the South Pole.)
Other currents carry cold water from the poles toward the equator. As these currents flow along the edges of land masses, they affect the temperature of coastal regions.
Many different types of animals live in the oceans. One type is a tiny organism called plankter.
Plankton (more than one plankter) drift on ocean currents. Some plankton are plants. Some are animals. Many other ocean animals eat plankton.
Many kinds of fish live in the oceans. They include eels, sharks, swordfishes, and tuna. Shellfish live in oceans too. Among them are shrimp, crabs, and lobsters.
Mammals also live in oceans. Mammals are warm-blooded animals that give birth to live babies instead of laying eggs. Some ocean mammals are manatees, dolphins, seals, walruses, and whales.