From Surface to the Abyss: The Evolution of Deep Ocean Exploration

By the end of the nineteenth century, the world’s oceans had been completely explored, at least on the surface. For the previous 3,000 years, most ocean exploration was concerned with finding ways to get from one place to another, finding new lands, and developing oceanic trade. Practical knowledge was valued: information about water depth, currents, winds, reefs, and rocks—all things that could present a danger to ocean transport. In the twentieth and twenty-first centuries, scientists turned their attention to what lay below the surface, to the deep ocean. The new field of oceanography emerged as the science of the ocean.

Though early civilizations expressed a curiosity about what lay in the deep ocean, it was difficult to conduct research on this. Some scientists, such as the American Benjamin Franklin (1706-90), began to compile information about the ocean, especially its currents, from sailors. But the field of modern oceanography really began with the Confederate soldier and scientist Matthew Fontaine Maury (1806-73). Maury compiled information about ocean currents and winds and published many books on this subject. These publications helped spread the idea of oceanography as a science and helped stimulate interest in knowing more about the oceans. A British oceanographic expedition during 1872-6, on the ship Challenger, was a result of this growing interest and gathered much new information from the area around Bermuda in the Atlantic.

In the twentieth century, new technologies such as submarines and submersibles made exploring below the ocean surface possible. Though submarines were invented around the time of the American Civil War, they were used then for military purposes. Later, in the twentieth century, smaller submarines were developed for scientific exploration. New oceanographic technology helped discover 40,000 miles of mountain ridges under the ocean surface and helped establish the theory of plate tectonics that provided an explanation for continental drift. Submersibles also documented the existence of marine microbes that could withstand extremely high temperatures near underwater volcanic vents. Today, submersibles can descend more than four miles into the ocean depths.

In 1943, French oceanographer Jacques-Yves Cousteau (1910-97) developed what he called Aqua-Lung which allowed humans to breathe while underwater. Aqua-Lung was adopted by the US Navy and rebranded as the Self-Contained Underwater Breathing Apparatus, or SCUBA. This technology allowed divers to explore at greater depths (and also led to a popular form of recreation). Cousteau’s ship Calypso made numerous voyages across the world from the 1950s to the 1980s, collecting scientific information about the world’s oceans. Cousteau also developed an underwater camera to aid in his research.

Mapping the Ocean Floor through Tragedy. The search for Malaysia Airlines Flight 370 between 2014 and 2017 yielded little information about its disappearance. The great expenses involved in locating debris as well as voice recorders on the bottom of the ocean, however, did provide new information about the remote parts of the Indian and Southern Oceans. It is estimated that only 5 percent of the ocean floor is currently mapped, and scientists rightfully point out that we know more about our solar system than about the oceans” depths. The high costs associated with the sensitive imaging material made the search for MH370 fortuitous. Although the search for the airliner was officially suspended in early 2017, scientists managed to map close to 100,000 m² of the ocean floor and will soon release this information to an interested public. Rainer F. Buschmann.

Exploration of the deep sea and oceanographic research continue in the twenty-first century. The deep oceans are the last unexplored places on Earth. Even today, explorers are continuing the more than 3,000-year-old tradition of ocean exploration. Michael Pretes.

Further Reading: Fagan, Brian. 2012. Beyond the Blue Horizon: How the Earliest Mariners Unlocked the Secrets of the Oceans. New York: Bloomsbury Press.

Fernandez-Armesto, Felipe. 2006. Pathfinders: A Global History of Exploration. New York: W W Norton.

Lavery, Brian. 2013. The Conquest of the Ocean. New York: DK Publishing.

Mack, John. 2011. The Sea: A Cultural History. London: Reaktion Books.

Paine, Lincoln. 2013. The Sea and Civilization: A Maritime History of the World. New York: Vintage Books.

Rozwadowski, Helen M. 2005. Fathoming the Ocean: The Discovery and Exploration of the Deep Sea. Cambridge, MA: Belknap/Harvard University Press.