The ocean keeps the Earth alive. Covering around 70 percent of our planet's surface, the ocean regulates temperature, drives weather, and supports all living organisms in some way. For centuries, it has also provided humans with food, transport, commerce, leisure, and inspiration.
Lack of technology, high cost, and difficulty have hindered deep underwater exploration, but that's not to say humans haven't tried for, and even achieved, inspiring feats of ocean exploration. From inventing new types of submersibles to new ways of kicking with their own two legs, innovators, explorers, and sportspeople have reached unthinkable depths through a number of impressive methods.
The deepest salt-water scuba dive
Dark, cold, and hostile are words that come to mind when thinking of deep-sea diving. But as the saying goes, when there's a will, there's a way, and Egyptian scuba diver Ahmed Gamal Gabr certainly has a will.
Reaching an unimaginable 1,090 feet 4.5 inches (323.35 meters), Gabr gained the Guinness World Record title for the deepest scuba dive. To put it into perspective, the Chrysler Building in New York City stands 1,046 feet (319 meters) tall — Gabr dove to a depth deeper than the height of the Chrysler Building.
The 41-year-old dive instructor took the plunge on September 18, 2014, in the Red Sea, off the coast of Dahab in Egypt. He had 17 years of experience at the time and trained for four years for his feat, which goes to show just how much work goes into deep-sea diving.
Interestingly, the descent took him only around 12 minutes. On the other hand, his ascent took him nearly 15 hours, due to the requirements of decompression. All in all, he used nine tanks filled with a mixture of oxygen, nitrogen, helium, and hydrogen to achieve his record dive. His support crew carried around 90 bottles in total.
Scuba diving is a beloved sport around the world, and to be allowed to dive people have to first pass a test and receive training from a certified association like PADI.
The most common diver's license is the PADI Open Water certification, where divers can descend to 60 feet (18 meters). The Advanced Open Water license allows divers to go to depths of 80 feet (30 meters). Divers have to get new certifications for different depths and environments such as caves, wrecks, night-time, etc.
It's an extremely controlled and specific sport because if you come up too quickly or don't measure enough air for your dive, for instance, the repercussions can be fatal. So when Gabr broke the record in 2014, he proved humans can reach staggering depths, and still survive the extreme conditions of deep-sea diving.
Deepest free dive
Humans haven't only been diving to incredible depths with scuba equipment, though. In a discipline called freediving, people have managed to reach hundreds of feet beneath the water's surface using only the air they bring with them in their lungs.
Used by pearlers and fishers for thousands of years freediving is an underwater discipline where divers use breath control to enable them to spend long periods without breathing. Simply put, divers take one breath and then dive down. That said, there's a lot of special breathing techniques professional freedivers use, and they train for years before it's safe for them to go deep down.
Known as "the Deepest Man on Earth," Herbert Nitsch made it down to 702 feet (214 meters) in just a single breath. Adding to his already impressive 33 freediving world records, Nitsch gained another title at the world's deepest and most extreme freediving discipline, the No Limit dive challenge, in Spteses, Greece in June 2007. At that event, he dove to 830 feet (253 meters).
Nitsch can hold his breath for more than nine minutes. That's about eight and a half minutes longer than the average person.
To put it into perspective, there are only four freedivers in the world who have made it past 560 feet (170 meters), and two of whom have tragically died trying. Nitsch, so far, is the only person to have officially made it past those depths with just one breath.
Deepest shipwreck dive
When humans aren't diving to incredible depths with the use of scuba equipment or their own breath, they're doing so in motorized submersibles equipped with incredible technology.
This year, a crewed expedition successfully completed the world's deepest shipwreck dive in history, made in the submersible DSV Limiting Factor, developed by Caladan Oceanic. The wreck, the deepest shipwreck ever located, is of the USS Johnston, a US Navy destroyer that sank on October 25, 1944, during WWII. The vessel now sits 21,180 feet (6,456 meters) underwater off the coast of the Philippines.
The wreck was originally discovered in 2019 by Robert Kraft and his team, who filmed pieces of the shipwreck using a remotely-operated vehicle (ROV). However, as the ROV could only reach a maximum depth of 20,000 feet (6,000 meters), part of the wreck was beyond its reach.
So, this year, when Victor Vescovo piloted the highly-maneuverable DSV Limiting Factor submersible down to the full depth of the wreck, he and his team completed the world's deepest crewed wreck dive in history. They went down twice for eight hours at a time, filming and taking pictures of the historical dive.
Deepest submersible dive
That's not all Vescovo and the DSV Limiting Factor submersible have achieved. Well known in the diving world, the American explorer and his submersible also shaped diving history in 2019.
Before this year's USS Johnston shipwreck dive, Vescovo piloted his submersible to the deepest points in each of the world's five oceans as part of the "Five Deeps Expedition".
During that expedition, Vescovo successfully piloted his submersible down to the Challenger Deep in the Pacific Ocean. The Challenger Deep lies in the Mariana Trench and is approximately 36,200 feet (11,034 meters) deep — it's known as the deepest underwater point on Earth, and is deeper than Mount Everest is tall.
On May 13, 2019, Vescovo became the first person on Earth to reach a depth of 35,853 feet (10,927 meters), and the third person to ever descend to the Challenger Deep.
The last visit to the bottom of the Challenger Deep was made by filmmaker and explorer James Cameron in 2012 when he reached a depth of around 35,787 feet (10,908 meters) aboard the Deepsea Challenger submersible. The first-ever dive down to the Challenger Deep was in 1960 when Lieutenant Don Walsh and Swiss scientist Jacques Piccard made it to about 35,800 feet (10,911 meters) in the Trieste submersible.
All of these feats are incredibly impressive. It has to be pointed out that both the Deepsea Challenger and the Trieste submersibles dove down to the Challenger Deep once, whereas the Limiting Factor submersible made a total of four dives down into the Mariana Trench.
Deep-sea exploration and its relevance
As you can see, diving to the ocean's deepest points is no easy task. In nearly six decades, only three men have made it to the bottom of the ocean. In comparison, 24 people have traveled beyond low-Earth orbit in just the four years between 1968 and 1972, not to mention the many that have made the trip since.
Intense physical pressure and difficulty on the human body make diving down to such depths dangerous. Moreover, the high cost of developing the correct technology for underwater vehicles makes deep ocean dives and exploration tricky. But is that any harder than developing astronaut suits and space vehicles? We're not so sure.
That's not to say we should favor ocean exploration over space exploration, but understanding what's happening closer to home could have a deep impact on our lives. For instance, we could learn to more effectively manage, conserve, regulate, and use ocean resources that are crucial to our economy and our lives - and environment.
Through ocean exploration, we collect information and data that help address current and future needs, explains the National Oceanic and Atmospheric Administration (NOAA). It helps conservation and sustainability efforts, as well as helping us better understand and respond to natural events like earthquakes and tsunamis. It also pushes forward new technological advancements that could be used in other environments.
Certain corporations and explorers, including NOAA, are putting effort into ocean exploration, but it takes time. Until then, we're sure to see new deep-sea diving records broken, and humans pushing the limits of what's possible. For now, it's time to practice holding your breath for nine minutes.