Amazing Facts About the Earth's Oceans

You've probably heard that the majority of our planet's surface is covered by oceans. (Specifically: It's a hair shy of 71 percent.) What you might not have heard, though, is that sea waves can move at hundreds of miles per hour. Or that the ocean's depths are home to millions of tons of gold. Or that scientists have more detailed, more extensive maps of Mars than of our own oceans.

Yes, as deep as our planet's oceans are in terms of sheer liquid, they're deeper still when it comes to mystery and fascination. And these little-known facts about the ocean are sure to blow you out of the water.

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The ocean is home to nearly 95 percent of all life.

With so much going on well below the surface, it's easy to forget that the oceans are teeming with life. In fact, 94 percent of life is aquatic, according to the USA Science & Engineering Festival. That means those of us who live on land are part of a very, very small minority.

The ocean is a huge body of saltwater that covers about 71 percent of the Earth’s surface. The planet has one global ocean, though oceanographers and the nations of the world have divided it into distinct geographic regions: the Pacific, Atlantic, Indian, and Arctic oceans. In recent years, some oceanographers have determined that the seas around Antarctica deserve their own designation: the Southern Ocean.

An estimated 97 percent of the world’s water is found in the ocean. Because of this, the ocean has considerable impact on weather, temperature, and the food supply of humans and other organisms. Despite its size and impact on the lives of every organism on Earth, the ocean remains a mystery. More than 80 percent of the ocean has never been mapped, explored, or even seen by humans. A far greater percentage of the surfaces of the moon and the planet Mars have been mapped and studied than our own ocean floor has.

Although there is much more to learn, oceanographers have already made some amazing discoveries. For example, we know that the ocean contains towering mountain ranges and deep canyons, known as trenches, just like those on land. The peak of the world’s tallest mountain—Mount Everest in the Himalayas, measuring 8.84 kilometers (5.49 miles) high—would not even break the surface of the water if it was placed in the Pacific Ocean’s Mariana Trench or Philippine Trench, two of the deepest parts of the ocean.

On the other hand, the Atlantic Ocean is relatively shallow because large parts of its seafloor are made up of continental shelves—parts of the continents that extend far out into the ocean. The average depth of the entire ocean is 3,720 meters (12,200 feet).

It is unknown how many different species call the ocean their home. With many marine ecosystems suffering from rising sea temperatures, pollution, and other problems, some oceanographers believe the number of species is dropping. Still, there may be many positive surprises awaiting oceanographers in the years ahead. It could be that more than 90 percent of the ocean’s species are still undiscovered, with some scientists estimating that there are anywhere between a few hundred thousand to a few million more to be discovered. Currently, scientists know of around 226,000 ocean species.

Learning more about the seafloor and the rest of the ocean is the passion of National Geographic Explorer Marcello Calisti. He is a biorobotics expert who is developing an undersea exploration vehicle that uses “legged locomotion,” inspired by the way an octopus moves under water. His long-range goal is to design robots that can explore the depths that are difficult for humans to reach.

Since the ocean is so vast, there is plenty for future oceanographers from all corners of the globe to explore and discover.

There's enough gold in the ocean for us each to have 9 pounds of it!

There's around 20 million tons of gold dispersed throughout the oceans. It is, however, diluted pretty much to a pulp—its concentration is only a few parts per trillion, according to the National Ocean Service. The ocean floor also has undissolved gold embedded in it, but it's not cost-effective to mine it. However, if the ocean's gold were equally distributed among every person on earth, we'd each receive nine pounds of gold.

Sharks have their own underwater "café."

It turns out, humans aren't the only creatures in need of a winter vacation. In 2002, scientists discovered an area in a remote part of the Pacific Ocean, partway between Baja California and Hawaii, where typically coastal great white sharks will migrate to in the winter. The scientists named the spot the White Shark Café and some sharks hang around the area for months before heading back to the coast for warmer weather.

Human impacts

Human activities affect nearly all parts of the ocean. Lost and discarded fishing nets continue to lethally snare fish, seabirds, and marine mammals as they drift. Ships spill oil and garbage; they also transport critters to alien habitats unprepared for their arrival, turning them into invasive species. Mangrove forests are cleared for homes and industry. Our garbage—particularly plastic—chokes the seas, creating vast "garbage patches" such as the Great Pacific Garbage Patch. Fertilizer runoff from farms turns vast swaths of the ocean into dead zones, including a New Jersey-size area in the Gulf of Mexico.

Climate change, the term scientists now use to describe global warming and other trends currently affecting the planet because of high greenhouse gas[1] emissions from humans, is strikingly reflected in the oceans. The year 2018 marked the oceans’ hottest year on record, and warmer waters lead to a range of consequences, from changing colors to rising sea levels to more frequent powerful storms. The greenhouse gas carbon dioxide is also turning ocean waters acidic, and an influx of freshwater from melting glaciers threatens to alter the weather-driving currents: the Atlantic Ocean's currents have slowed by about 15 percent over the past few decades.

A community of scientists, explorers, and citizen scientists continues to study the ocean, hoping that more information will yield more paths for conservation. Underwater drones, for example, are being deployed to explore undersea frontiers, while new tools are helping scientists measure and understand what they find. Read more about ocean threats and solutions here.

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