The Atlantic, Pacific, Indian, Arctic, and Southern Oceans are the interconnected bodies of salt water that cover about 71% of Earth's surface. Containing 97% of the planet's surface water, oceans harbor an estimated 2 million marine species, including the photosynthetic algae that produce half of all atmospheric oxygen. The oceans buffer against abrupt climate change and regulate and redistribute moisture and solar energy through interactions with the atmosphere, supporting widespread planetary biodiversity.
> Who decided how to divide the world ocean into multiple oceans?
> The Southern Ocean's unique environment led to its recognition as the fifth ocean.
> Watch a breathtaking visualization of global ocean currents, as if seen from space.
The water that formed the oceans is hypothesized to have been expelled from Earth's interior by volcanoes before condensing as precipitation, though some may have been delivered by comets and asteroids. Geologic dating of rocks formed only during underwater eruptions or when sediments accumulated in underwater layers indicates that oceans formed at least 3.8 billion years ago. These underwater volcanoes, alongside runoff of minerals from eroded rocks, continue to add salts to seawater, which many organisms extract to build shells and skeletons.
> Earth's thick early atmosphere may have enabled the first oceans to be over 440 degrees Fahrenheit without boiling.
> Hot springs on the seafloor provide minerals that sustain rich underwater ecosystems kept warm by magma.
> Take an animated dive to the seafloor and view the animals that populate oceans.
By absorbing more than 90% of the excess thermal energy trapped by greenhouse gases, the oceans fuel extreme weather events, such as hurricanes, and can amplify climate patterns, such as El Niño. Oceans also absorb 30% of carbon dioxide emissions, with the resulting acidification threatening marine life, habitats, and food webs.
> The top several meters of the world's oceans can hold as much thermal energy as the entire atmosphere.
> Since the Industrial Revolution, surface ocean waters have become 30% more acidic.
Discover more:
> The world's ocean currents form a global conveyor belt that takes water about a thousand years to travel through.
> The names of Earth's oceans come from geography, Greek mythology, and Ferdinand Magellan.
> Is there any truth to viral videos that show two different-colored bodies of water meeting and claim that oceans do not mix?
Keep learning by exploring all our findings on Oceans here.
