Humans have been exploring the oceans since the first sailing vessels left the shores of Egypt more than 6,000 years ago.
It’s easy to assume that during that time and with our modern technologies, we would have discovered everything there is to know about the oceans. However, the latest estimates suggest that less than 10% of the world’s seabed has been accurately mapped.
So, while we may have accurately mapped areas close to home, discovered new species, and explored shipwrecks, our understanding of the ocean is far from complete.
As we answer “how much of the ocean have we discovered?” we’ll look at the history of ocean exploration and explore the current state of this highly challenging science. We’ll also explain why continual ocean exploration is essential and how it can help humanity in the future.
How Much of the Ocean Have We Discovered?
The five ocean basins cover 71% of our planet, contain 97% of the water, and are, without a doubt, the lifeblood of the Earth.
Despite our reliance on the ocean, the National Oceanic and Atmospheric Administration report that more than eighty percent of the ocean floor has not yet been mapped, let alone directly explored. Less than ten percent of the seabed has been precisely mapped using modern sonar technology.
Even in the coastal waters of the United States, only about 35 percent of the ocean floor has been mapped accurately.
The lack of knowledge is due to several factors, mainly the immense size of the ocean, the incredible depth, and its extreme inaccessibility.
As we will discover, it’s not just mapping the seabed that is important. Understanding life in the deep ocean and how the environment is changing gives us considerable insight into the health of our planet.
Without the ocean, there wouldn’t be any life as we know it above or below the surface. The planet’s water cycle would be broken. We would be starved of oxygen as scientists estimate that 50-80% of the vital gas produced on our entire planet comes from the ocean.
The oceans also play a massive role in regulating the temperature of our planet and absorb much of the carbon dioxide produced by both natural and industrial activities.
Further, the ocean provides food, transportation, energy, commerce, and even medical advances.
So, with the ocean being essential to our planet, studying it is of the utmost importance.
To understand how much of the ocean we have explored, it is important to differentiate between the ocean’s water and the seafloor.
In terms of the water close to the surface, we have explored a significant amount. We have mapped and continue to observe the ocean’s currents and tides and studied its chemical composition and surface temperatures, thanks, in part, to modern satellite technologies.
However, our knowledge of the deep ocean and the seafloor is still very limited.
History of Ocean Exploration
Ocean exploration began when the first humans left their lands on rafts to catch food or travel short distances. However, oceanography is a relatively young science that explicitly studies the oceans.
The ancient Egyptians launched the first sailing ships around 4000 BC, and their version of ocean exploration will have focused on the winds to get to where they wanted to, observing the tides, and trying to check how deep the water was so they didn’t run aground.
The ancient Greeks and Romans, Phoenician sailors from the eastern Mediterranean, Viking seafarers in Northern Europe, and Chinese and European sailors, amongst others, traveled impressive distances. Still, exploration below the surface remained limited mainly to navigational needs.
Some of the first significant attempts to map ocean depths were made in the 19th century. The French explorer Jules Sébastien César Dumont d’Urville used lead-weighted ropes to measure depths in the Mediterranean Sea. He went on to produce the most accurate charts of the time of the South Pacific and Antarctic.
In 1913 echo sounding was invented in Germany, and ocean measurements took a giant leap forward. Between 1925 and 1938, the German vessel Meteor traveled the Atlantic Ocean, mapping the seabed using the newly invented sonar equipment.
While the modern submarine was invented in the 19th century, the first people to directly observe the deep ocean were the Americans Otis Barton and William Beebe in the 1930s. They descended as far as 923 meters (3,028 feet) in their tethered Bathysphere submersible during multiple dives off the coast of Bermuda.
Advances in the twentieth century, much of it from the second world war, including the development of better sonar and echo-sounding technology, gave researchers the ability to map the sea bed with increasing accuracy from their ships.
Meanwhile, deep ocean submersibles, including the Trieste bathyscape in 1960, allowed men to visit even the deepest part of the ocean, the Mariana Trench.
It was satellite technology that created the next significant step in ocean exploration. Satellites allowed scientists to measure vast sea areas in much less time than was possible for research vessels.
Satellites bounce radar beams off the ocean’s surface and use the data received to measure variations in height, which can be used to create maps of the sea bed.
Finally, in 2017 the Seabed 2030 project was launched with the aim of entirely and accurately mapping the ocean floor by 2030.
Current State of Ocean Exploration
We’ve explored most of the Earth’s shallow coastal waters and have broadly mapped the ocean floor, albeit perhaps not as accurate as we’d like.
We’ve also discovered an enormous variety of marine life, from the tiniest plankton to giant whales.
However, there are still many mysteries left to uncover. Thousands of new species of marine life are left to still be discovered, particularly in the deep ocean trenches.
Specifically designed research vessels are used worldwide to map the ocean floor using advanced multibeam echosounder sonar.
Satellites monitor ocean currents, measure water temperatures, and track marine life. They are also used to detect oil spills and other environmental hazards.
However, they can only measure the surface, and much of the vital information lies in the deep ocean. Scientists are using submersibles, remotely operated vehicles (ROVs), and autonomous underwater vehicles (AUVs) to explore “in person” at depths and bring back footage with a previously unimaginable clarity.
One of ocean research’s most critical areas is climate change. Changes in water temperatures in the deep oceans give us a considerable amount of information about what is happening to our planet. These readings must be made “in-person” and repeatedly to track the changes.
In addition, the study of new life found around high-temperature hydrothermal vents is leading researchers studying global warming to consider ways they may preserve shallow marine life.
The effects of human activities have also been noticed by discovering plastics and other artificial waste in even the most remote depths of the sea.
On a more commercial level, the deep seabed is also being explored to search for valuable oil, gas, and rare mineral deposits.
Deep Sea Exploration
The deep sea is defined as the region of the ocean below 200 meters (656 feet). Here, the continental shelves transition into steep continental slopes, and the last rays of sunlight fade from even the clearest waters.
The average depth of the world’s oceans is an astonishing 3,688 meters (12,100 feet), and the area of the sea bed at less than 200 meters accounts for just 7 percent of the total.
Low water temperatures between −2 °C (28 °F) and 5 °C (41 °F) and the lack of sunlight make the deep ocean a challenging environment. However, it is the extreme water pressure that makes it such an extremely difficult environment to explore.
At the deepest point at the Challenger Deep section of the Mariana Trench, the Pacific Ocean sea bed lies at about 10,984 meters (36,037 feet). The water pressure here exerts 1,086 bars of pressure or, as often explained, the equivalent of more than 100 adult elephants.
Even at lesser depths, the still significant pressure means that incredible and costly engineering is required to send scientific devices into the ocean, let alone human explorers.
Ocean exploration technology is relatively new. Human beings have always explored the ocean’s surface, but only in the last few decades could we start discovering its depths for ourselves.
Even the most advanced remote vehicles are limited in range and time to stay underwater. Divers in submersibles can only stay for short periods due to needing to carry oxygen, food, water, and power and because of the lack of comfort in the cramped underwater vehicles.
So, all in all, exploring the deep sea is a highly complex endeavor.
Consider, too, the vast size of the ocean. At nearly 71% of our planet’s surface area, fully exploring it will take a staggering amount of time and resources.
Mapping the Ocean Floor
Mapping the ocean floor is essential for understanding the ocean environment. Thankfully, ocean exploration technologies have come a long way from throwing a rope over the side of a ship and waiting for it to find the bottom.
Researchers use their high-resolution multibeam sonar to produce three-dimensional ocean floor images and create maps with unprecedented detail. These maps improve our understanding of the geology of the ocean and have revealed the locations of underwater mountains and trenches.
Specific sites of interest can then be examined more closely using human-occupied vehicles (HOVs), remotely-operated ones (ROVs), and autonomous ones to collect samples to study and take photos and video.
While unoccupied vehicles are more cost-efficient, many, including the famous director and ocean pioneer James Cameron, believe that human expeditions are needed to inspire future ocean research and conservation.
As he says, “The most important aspect of exploration, in my mind, is coming back and telling the tale.”
Discoveries Made in the Ocean
The exploration of the deep ocean has led to many remarkable discoveries.
Deep-sea hydrothermal vents spewing hot, mineral-rich water into the surrounding ocean revealed a unique ecosystem containing new species of fish, worms, and even communities of bacteria that can survive in the toxic water.
Exploring the ocean floor has also revealed beautifully preserved examples of human history in the form of shipwrecks. These have been kept out of the reach of almost all destructive life forms.
In many areas, accurately mapping the seabed has been the first step in protecting it while discovering new species along the way.
The leader of the Oceana expedition in Chile, Ricardo Aguilar, said, “We only have good information on less than 5% of the world’s oceans, and maybe sparse information on another 10%. Therefore, how can we protect areas where we have no clue what is there?”
Ongoing Research in the Ocean
Scientists are constantly studying everything from marine life and ecosystems to the geology of the ocean floor to increase their understanding of the ocean environment and its effects on the planet.
Researchers are also exploring to identify new sources of energy, minerals, and other resources.
A significant area of ongoing research is the study of climate change. The ocean plays a vital role in regulating the Earth’s climate, and as the climate changes, so does the sea.
For example, researchers from the British Antarctic Survey are continually monitoring the interconnected and highly-complex polar atmosphere-ocean-sea-ice system to understand how climate change affects its delicate balance.
The ocean is also a vital source of food and resources for humans, with over 3 billion people relying on it as their primary protein source.
By studying the ocean’s ecosystems, we can learn more about how to sustainably manage these resources and better protect them from threats, including oil spills, plastic waste, and other human impacts.
With the majority of our planet being the blue ocean, it’s vital to understand it as much as possible for our future well-being.
The Future of Ocean Exploration
Technological advances are slowly making ocean exploration more straightforward and cheaper. This will lead to a dramatic increase in the data available, which should make protecting the ocean easier.
While there is a growing interest in understanding the ocean and its role in the world, exploration for commercial exploitation is also possible. The possibility of extracting vast amounts of valuable rare-earth elements from the sea bed is attractive. However, it will need to be balanced with protecting the environment.
Increasingly, governments worldwide are recognizing the value of their seas, and thanks to compelling scientific evidence, large oceans are being designated as protected zones. As research continues and improves, the significance of safeguarding larger areas will become clear.
As we’ve answered, “How much of the ocean have we discovered?” we’ve seen that the area of the sea bed that has been accurately mapped is only around 10% of the total.
While lower-resolution charts exist for the planet’s oceans, much of the ocean floor and the life above it remains a mystery.
The exploration of the ocean is ongoing and is recognized as increasingly vital. By studying our seas, we can learn more about their ecosystems and, in particular, protecting their essential role in our planet’s climate.
British-born Dan has been a scuba instructor and guide in Egypt's Red Sea since 2010.
Dan loves inspiring safe, fun, and environmentally responsible diving and particularly enjoys the opportunity to dive with sharks or investigate local shipwrecks.
When not spending time underwater, Dan can usually be found biking and hiking in Sharm's desert surroundings.