Why We Must Explore the Sea

Robert Ballard, the famed explorer who discovered the wreck of the Titanic, ponders what else is on the ocean floor

Why We Must Explore the Sea 1 Ocean Floor
The vast unknown deep sea floor © 13/Last Resort/Ocean/Corbis

Most people think the bottom of the ocean is like a giant bathtub filled with mud—boring, flat and dark. But it contains the largest mountain range on earth, canyons far grander than the Grand Canyon and towering vertical cliffs rising up three miles—more than twice the height of Yosemite’s celebrated El Capitan.

When you look at publicly available topographies of the seafloor, you can get the impression that the job of mapping the planet is over. Far from it. Even these seemingly precise representations, often based on satellite estimates of ocean depths, are not all that revealing. They’re rather like throwing a wet blanket over a table set for a fancy dinner party. You might see the outlines of four candelabras surrounded by a dozen chairs, perhaps some drinking glasses if the blanket’s really wet. But that’s about it. You wouldn’t see the utensils and plates, let alone what’s for dinner. Satellite data, in other words, only gives a rough idea of what lies beneath the sea.

Only a tiny percentage of the ocean floor has been carefully mapped, which means we know less about 71 percent of the Earth’s landscape than about the far side of the Moon. That’s a lot of terra incognita. More than half of the United States of America lies in the 200-nautical-mile exclusive economic zone extending out from its borders beneath the sea. If the country wants to extend its claim farther onto the continental shelf, and thus claim the trillions of dollars’ worth of oil and gas deposits probably found there, it needs to map those realms.

Exploration and mapping, and making the data open source, would be for the betterment of all citizens—not just in economic terms but in opportunities for unexpected discoveries. Meanwhile, too many ocean researchers go back to well-trodden regions.

In one way or another I’ve been mapping the ocean since 1967. After being assigned by the Office of Naval Research to the Woods Hole Oceanographic Institution, I soon found myself standing watch on the research vessel Chain as it steamed back and forth across the continental margin off the East Coast, equipped with an instrument that bounced sound waves off the bottom of the sea and gauged the return. But the smooth, curved landscape pouring from the wet paper recorder onboard barely resembled the submarine canyons the ship was passing over. We simply had to guess how deep each canyon was.

Years later I learned that the Navy had worked with General Instrument to produce a sophisticated sonar system yielding extremely accurate maps, but the system was secret and few oceanographers knew it existed. I saw what this sonar could produce in 1973 during Project FAMOUS (French-American Mid-Ocean Undersea Study), the first time scientists used deep-diving vehicles to explore the rugged volcanic terrain of the Mid-Atlantic Ridge in water depths of 10,000 feet and more. Similarly detailed maps helped guarantee the success of our historic expeditions to the Mid-Cayman Rise and Galápagos Rift in 1976 and 1977, including the discovery of the first hydrothermal vents and their exotic chemosynthetic life-forms.

Last year I mounted the latest multi-beam sonar on Nautilus, the vessel operated by the Ocean Exploration Trust, the nonprofit education and research organization I founded. The instrumentation makes highly accurate 3-D maps, discerns if the seafloor is hard or soft, and can even detect oil and gas in the water column.

We filled in holes in publicly available bathymetry, as the science of measuring ocean depths is known, between the Bahamas and Florida, where there is potential for underwater landslides that could generate tsunamis reaching the East Coast. Such maps can reveal slope instabilities. We worked with the National Oceanic and Atmospheric Administration to map a refuge for spawning fish near the Florida Keys National Marine Sanctuary and made some of the first maps around the Belize Barrier Reef.

One standout mission included surveys over natural gas seeps in the Gulf of Mexico, where we tracked gas bubbles from their source deep in the seabed. Then there are the cultural artifacts that so capture public imagination: Nautilus mapped the wreck of the U-166, the only German U-boat known to be sunk in the Gulf of Mexico during World War II.

All in all, our forays with Nautilus have mapped nearly 40,000 square miles of seafloor—a vast area the size of Kentucky, but a drop in the bucket compared with what’s left to do. Next year’s expeditions include trips south of the Equator for the first time. I can only wonder what waits for us in that hemisphere, where the ocean covers more than 80 percent of the area and where few explorers have ever been.

Get the latest Science stories in your inbox.