Skip links

List of Oceans and Facts for Kids

An ocean is a body of saline water that composes a large part of a planet’s hydrosphere. The word “sea” is often used interchangeably with “ocean”, but strictly speaking a sea is a body of saline water (possibly a division of the World Ocean) partly or fully enclosed by land. Earth is the only planet known to have an ocean. Because it is the principal component of Earth’s hydrosphere, the world ocean is integral to all known life, forms part of the carbon cycle, and influences climate and weather patterns. The total volume is approximately 310 million cu mi with an average depth of 12,080 ft.

  • It is the habitat of 230,000 known species, although much of the ocean’s depths remain unexplored and it is estimated that over two million marine species exist.
  • The only confirmed large stable bodies of extraterrestrial surface liquids are the lakes of Titan, although there is evidence for the existence of oceans elsewhere in the Solar System.
  • The Mars ocean hypothesis suggests that nearly a third of the surface of Mars was once covered by water, though the water on Mars is no longer oceanic, and a runaway greenhouse effect may have boiled away the global ocean of Venus.
  • Compounds such as salts and ammonia dissolved in water lower its freezing point, so that water might exist in large quantities in extraterrestrial environments as brine or convecting ice.
  • Unconfirmed oceans are speculated beneath the surface of many dwarf planets and natural satellites; notably, the ocean of Europa is believed to have over twice the water volume of Earth.
  • The Solar System’s gas giant planets are also believed to possess liquid atmospheric layers of yet to be confirmed compositions.
  • The area of the World Ocean is 139 million square miles, and its volume is approximately 310 million cu mi.
  • The vast expanses of deep ocean cover about 66% of the Earth’s surface.
  • Oceanographers divide the ocean into different zones depending on the present physical and biological conditions.
  • The pelagic zone includes all open ocean regions, and can be divided into further regions categorized by depth and light abundance.
  • The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean near the Northern Mariana Islands.
  • Surface heat and freshwater fluxes create global density gradients that drive the thermohaline circulation part of large-scale ocean circulation.
  • While Earth is the only known planet with large stable bodies of liquid water on its surface and the only one in our Solar System, other celestial bodies are believed to possess large oceans.
  • Likewise the ice giants of Uranus and Neptune may also possess vast oceans of liquid water under their thick atmospheres, though their internal structure has not been confirmed.
  • Some planets and natural satellites beyond the Solar System are likely to possess oceans, including possible water ocean planets similar to Earth in the habitable zone or “Liquid Water belt”.

List of Earths Oceans

Pacific Ocean
Atlantic Ocean
Indian Ocean
Southern Ocean
Arctic Ocean