Just as landmasses have been divided into distinct nations, the world ocean has been divided into multiple oceans for various geographical, practical, and scientific reasons.

The Southern Ocean features the Antarctic Circumpolar Current—the largest ocean current on Earth—which encircles Antarctica and creates a unique biogeographical zone.

Earth's oceans do mix, despite viral images and videos claiming to show boundaries between oceans that waters do not cross.

The Atlantic Ocean was named after Atlas, who holds up the sky in Greek mythology, while the Pacific Ocean was named by Ferdinand Magellan.

Surface ocean currents are primarily driven by wind, tides, and Earth's rotation, while deep-ocean currents are driven by differences in temperature and salt concentration.

A simple pictorial explanation of ocean geography

Visualizing ocean geographical features, such as a coastal zone, continental shelf and abyssal plain. This article from the US Geological Survey also provides several links to diverse ocean facts.

The top several meters of the world's oceans can hold as much thermal energy as the entire atmosphere.

The Antarctic Circumpolar Current is Earth's most powerful ocean current and carries more than 100 times the combined flow of all Earth's rivers.

Although an estimated 99.999% of the deep ocean has not been explored, techniques such as sonar have been used to identify the deepest known point in each of Earth's five oceans.

Earth's oceans, which have an average depth of 3.7 kilometers (2.3 miles), may be divided into zones based on depth or the abundance of light.

Watch a visualization of global ocean currents from NASA's Estimating the Circulation and Climate of the Ocean project.

What's the difference between an ocean, sea, and saltwater lake?

What are the seven seas, the five oceans, and why isn't the Dead Sea considered a sea? This overview provides definitions for each.

Mapping the route options between the Pacific and Atlantic

This map shows some of the alternative trade route options that are available to shipping companies, from overland routes that rely on railways to transport goods coast-to-coast, to Arctic Ocean passages.

Watch a visualization of how Earth's oceans impact its atmosphere, weather, and climate.

No map of the Earth is perfect because each introduces inaccuracies in the shape, size, or orientation of landmasses and oceans by trying to flatten the planet's curved surface.

The Ocean Observatories Initiative aims to provide freely accessible, real-time ocean data for up to 30 years to help scientists identify and analyze short- and long-term ocean processes.

Null Island is located at a latitude and longitude of 0°

A buoy denotes the fictional island where the Prime Meridian intersects with the equator in the Atlantic Ocean. Nations had disagreed on where the "origin" of world maps should be located until the Prime Meridian and Greenwich Mean Time were established in 1884.

How the ocean is the new frontier of innovation

Space has been called the final frontier of innovation and investment for decades. Many innovators say the ocean is the new space, the vast majority of whose hidden depths remain obscure. In this podcast episode, business-minded experts discuss the opportunities founders see in the ocean, including seagrass restoration, underwater cable networks, and more.

The history of deep-sea mining and its governance by the International Seabed Authority

The British HMS Challenger research vessel identified metal-rich seafloor rocks between Hawaii and Mexico in the 1870s, but rules governing which nations control which parts of the ocean were not established until 1958 by the UN. It later established the ISA to oversee mineral-related operations in international waters.

How salt, sunlight, and wind drive ocean currents

The Atlantic Meridional Overturning Circulation plays a critical role in regulating earth's climate, but is threatened by climate change. Explore the effects of temperature, density, and salinity on ocean currents in this 13-minute PBS video.

American oceanographic cartographer Marie Tharp's discovery of the Mid-Atlantic Ridge, which supported the idea that continents move over time, was initially dismissed as 'girl talk.'

The Rodinia supercontinent triggered a global ice age when it broke 750 million years ago

Before Pangaea, the Earth’s continental plates had drifted together and broken apart multiple times, with each event altering atmospheric CO2 concentrations and triggering climate change. The continents are estimated to come together again in 50 million to 250 million years.

Around 380 underwater cables power the Internet across the world.

On July 29, 1858, two steam-powered battleships met in the middle of the Atlantic Ocean. There, they connected two ends of a 4,000 kilometer (2,500 mile) long, 1.5 centimeter (0.6 inch) wide cable, linking for the first time the European and North American continents by telegraph.

National Geographic presents how to protect the oceans

What can we do to protect and preserve the world's oceans? Be inspired by spectacular wildlife footage from National Geographic while learning key strategies.

Wine is divided between Old World and New World

The distinction stems from both geography and winemaking technique and tradition. This video breaks down how different viticultural regions fit into each category and the common traits of both Old World and New World wines. It also provides helpful tips for reading Old World wine labels.

The ocean's ability to store carbon long-term is being hindered by marine heatwaves

More than 4,000 robotic floats with biogeochemical data sensors, including oxygen, pH, nitrate, suspended particles, chlorophyll, temperature, and conductivity, have been deployed as part of the Global Ocean Biogeochemical Array. They have identified changes to ecosystem structure affecting the ocean's ability to transport carbon from surface waters into the deep.

Scientists determined that tectonic plates moved the ocean floor by observing symmetric patterns of magnetic stripes on opposite sides of underwater volcano systems, which could only result from seafloor spreading.

Visualizing changes in ocean temperatures between 2016 and 2020

How much does the temperature of the sea change in a given year? This visualization helps illustrate the changes by showing sea surface temperature data from January 2016 through March 2020. Sea surface temperature, which refers to water temperature at the sea's surface, plays a significant role in climate and weather.

The US Board on Geographic Names is responsible for ensuring uniform usage of geographic names within the government.

The British Antarctic Survey created a map of what Antarctica would look like if it lost all 27 million cubic kilometers (6.5 million cubic miles) of its ice—enough to fill almost 6,500 Grand Canyons.

The world's quirkiest time zones

In contrast to telling time by physical signs like the sun or stars, cultural time relies on political agreement and standards. The convention of time zones arose due to transportation and communication advancements, and while many work just fine, some are pretty wild. Chief among those is the time zone of the uninhabited Baker and Howland Islands in the central Pacific, which results in a technical 26-hour day.

Explaining why animals don't cross this invisible line in Indonesia

Although the distance separating the two regions is small, East and West Indonesia have starkly different species, puzzling scientists for decades. Biogeographers use the theory of plate tectonics to explain the phenomenon, arguing the two regions...

Railroads and long-distance communication led to the development of time zones, with Greenwich established as the prime meridian—the longitude of 0 degrees—due to British advancements in star mapping and navigation.

Compare the true sizes of continents, countries, and other regions around the world by dragging them across a Mercator projection.

What animals live in the ocean?

The oceans host an incredible diversity of fascinating species. Oceana's Marine Life Encyclopedia beautifully presents facts and photos of ocean animals from Atlantic Cod to Zebra Sharks.

The history of the world map

What did people used to think the world looked like? From the beginning of human history to right before the age of exploration, learn how the world maps were created.

NASA explores Earth's deepest oceans to prepare for space

By studying extreme environments in Earth's hadal zone—the deepest part of the ocean —NASA tests technologies, probes life under crushing pressure, and gathers clues about potential oceans and possible life on worlds like Europa and Enceladus.

Scientists define sea level as the elevation to which water would settle on Earth's surface, given the planet's gravitational field and rotation.

Tropical cyclones are called hurricanes, typhoons, and cyclones around the world

Tropical cyclones are named differently based on their region of origin due to historical traditions and cultural importance. These storms are called hurricanes in the Atlantic and northeast Pacific oceans, cyclones in the southwest Pacific and Indian oceans, and typhoons in the northwest Pacific Ocean.

Learn about various ocean-atmosphere cycles impacting global weather patterns

Although the El Niño-Southern Oscillation is among the most impactful, the North Atlantic Oscillation strongly influences weather patterns in the Northeast US by periodically changing atmospheric pressure over the Atlantic. The North Pacific Oscillation fluctuates atmospheric pressure and sea-surface temperatures that affect winter temperatures over much of the US.

View a map of the distribution of mineral resources on the seafloor

Polymetallic nodules are found in regions near the middle of the Pacific Ocean, along the eastern coast of South America, and along the western coast of Africa, while cobalt-rich crusts span significant portions of the Pacific tropics east of the Philippines. Polymetallic sulfide deposits occur at tectonic plate boundaries, including areas within national jurisdictions.

Earth's first oceans may have been as much as 230 degrees Celsius (446 degrees Fahrenheit), with atmospheric pressure preventing them from boiling.

The world's largest deserts—areas that receive less than 10 inches of annual rainfall—are led by the Antarctic and Arctic regions.

The missing continent that took 375 years to find

It took scientists 375 years to discover the eighth continent of the world, which had been hiding in plain sight all along. But mysteries still remain.

How glaciers melt

Greenland and Antarctica are home to most of the world's glacial ice, including its only two ice sheets, making them areas of particular interest to scientists. Watch this three-minute video to learn why understanding them is not just interesting, but crucial to our near-term adaptability and our long term survival in a changing world.

How did Polynesian wayfinders navigate the Pacific Ocean?

Ancient Polynesian navigators used the sun, moon, stars, clouds, currents, and more to sail the seas. People of Southeast Asia began their voyages to the region now known as Polynesia in roughly 1500 BCE. They would settle a vast area of 15 million square miles, including hundreds of islands, moving from islands due to overpopulation or war. Such voyages dwindled in 1300 CE as societies became more rooted.

How scientists use data to anticipate the phases of the El Niño-Southern Oscillation

Sea-surface temperatures across various regions of the equatorial Pacific Ocean can be compared with ocean temperatures elsewhere in the tropics to identify anomalies that indicate where in the ENSO cycle Earth finds itself. The "Niño 3.4" region in particular—known as the Ocean Niño Index—is a key indicator of ENSO phase and intensity.

Why the ozone hole altered Southern Hemisphere jet streams and rainfall patterns

Ozone depletion over Antarctica shifted jet streams southward, drying Australia while increasing rainfall in Uruguay, Brazil, Paraguay, and Argentina. Around the turn of the millennium, these trends began to slow as the Montreal Protocol phased out ozone-depleting substances.

The Köppen-Geiger system divides Earth’s climate into five main categories

This classification system, developed by a German-Russian botanist and a German climatologist, results from differences in the intensity of solar radiation and rainfall in different parts of the world. Each category is further divided into multiple coded zones.

How melting ice impacts the whole world

Melting glaciers and ice caps are far from where most people live, but their impact can be felt across the planet. Visit four places—the American West, a Himalayan valley, the northern Atlantic, and Texas—with this immersive interactive to see the various impacts of melting ice around the world.

Records of Earth's magnetic field on the seafloor validated plate tectonics

Matching glacial, fossil, and rock records, mountain ranges, and continental shapes across oceans was insufficient evidence for continental drift. Precise measurements of magnetic minerals on the ocean floor revealed seafloor spreading, which could only be explained by moving landmasses.