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‘Five Deeps’ mission to explore mysterious ocean trenches

In this submersible, two people can descend to 11,000 meters and gather samples with a robotic arm.


By Erik Stokstad

He scaled Mount Everest and the highest peaks on the six other continents. He skied to the North and South poles. Now, Victor Vescovo, the multimillionaire co-founder of a private equity company in Dallas, Texas, wants to be the first person to visit the deepest point in each of the five oceans. This week, Vescovo was set to complete the first dive in the yearlong Five Deeps Expedition, piloting a titanium-alloy, 12.5-ton submersible down 8408 meters to the deepest part of the Atlantic Ocean, in the Puerto Rico Trench.

Five Deeps may look like a vanity project, but for scientists, it is a rare opportunity to study inaccessible, mysterious places. “If there wasn’t this rich guy, there is not any funding agency that would be willing to spend so much money to visit all those areas,” says Ann Vanreusel, a deep-sea biologist at Ghent University in Belgium. The expedition will yield high-resolution maps that could offer clues about how ocean trenches form when tectonic plates plunge into the mantle. The dives are also sure to spot new species, which will give researchers a chance to compare the ecosystems that have evolved in these isolated, exotic habitats. “Great insights could come when we can start comparing these ultradeep sites,” says Stuart Piertney, an evolutionary biologist at the University of Aberdeen in the United Kingdom.

The HMS Challenger Expedition, a pioneering voyage in the 1870s, showed that life exists across the deep ocean by trawling and dredging up creatures from as deep as 8000 meters. Since then, research trawls have netted cutthroat eels, snailfish, and other animals adapted to the cold and pressure. Some rely on bioluminescence to attract mates or prey in the darkness. Below 8000 meters, sea cucumbers and giant crustaceans called amphipods dominate.

Firsthand exploration of the trenches has been limited. People have reached the bottom of the Mariana Trench, the world’s deepest trench, only twice: in 1960, in the bathyscaphe Trieste, and in 2012, when movie director James Cameron descended in an $8 million custom submersible. In 1964, a French submersible descended 8385 meters to what was then thought to be the deepest part of the Puerto Rico Trench. The other three deeps have never been visited, although trenches elsewhere have been probed with remotely operated submersibles and autonomous landers. Landers can make measurements, record images, and collect samples before returning to the surface, but can’t be controlled or targeted.

Alan Jamieson, a marine ecologist at Newcastle University in the United Kingdom who designed some of these landers, now can visit multiple trenches himself, as the science leader for the Five Deeps Expedition. In March 2017, he received a cryptic phone call from Triton Submarines, a high-end manufacturer in Sebastian, Florida. After signing a nondisclosure agreement, Jamieson learned that Vescovo had bought a 68-meter-long research vessel from the U.S. government and commissioned Triton to build a submersible capable of diving to 11,000 meters. Designed for quick descents and ascents, the Limiting Factor has three acrylic portholes, leather seats for Vescovo and a passenger, and custom lithium batteries to power propellers for scooting along the sea floor. “When someone phones up and says, ‘We have a multi-multi-multi-million-dollar submarine that can do things that your own gear can’t,’ it seems like a logical step forward,” Jamieson says.

A rotating cast of 15 collaborators will join Jamieson on the mother ship, Pressure Drop. It has space for three scientists, a wet lab, and a $1.5 million multibeam sonar to map the sea floor and verify its deepest spots.

Race to the bottoms

The Five Deeps Expedition aims to reach every ocean’s deepest trench and seven other deep sites in 11 months.