Science - USA (2018-12-21)

1342 21 DECEMBER 2018 • VOL 362 ISSUE 6421 sciencemag.org SCIENCE

H

e scaled Mount Everest and the high-

est peaks on the six other continents.

He skied to the North and South

poles. Now, Victor Vescovo, the multi-

millionaire co-founder of a private

equity company in Dallas, Texas,

wants to be 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 Atlan-

tic 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 com-

pare 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 pio-

neering voyage in the 1870s, showed that

life exists across the deep ocean by trawl-

ing 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 pres-

sure. Some rely on bioluminescence to at-

tract mates or prey in the darkness. Below

8000 meters, sea cucumbers and giant crus-

taceans 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 submers-

ibles and autonomous landers. Landers can

make measurements, record images, and

collect samples before returning to the sur-

face, but can’t be controlled or targeted.

Alan Jamieson, a marine ecologist at New-

castle University in the United Kingdom who

designed some of these landers, now can

visit multiple trenches himself, as the sci-

ence leader for the Five Deeps Expedition. In

March 2017, he received a cryptic phone call

from Triton Submarines, a high-end manu-

facturer in Sebastian, Florida. After signing a

nondisclosure agreement, Jamieson learned

that Vescovo had bought a 68-meter-long re-

search 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 cus-

tom 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

Crewed sub aims to spot new species and gather rocks

OCEAN SCIENCE

In this submersible, two people can descend to

11,000 meters and gather samples with a robotic arm.

By Erik Stokstad

Atlantic

Ocean

Southern

Ocean

Indian

Ocean

Pacifc

Ocean

Arctic

Ocean

8408 meters 8183 m 7290 m

10,925 m

Mount Everest

8848 m

Expedition

route

5573 m

Puerto Rico Trench South Sandwich Trench Java Trench Mariana Trench Molloy Deep

Deep dive 1 Deep dive 2 Deep dive 3 Deep dive 4 Deep dive 5

Race to the bottoms

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

‘Five Deeps’ mission to explore

mysterious ocean trenches

CREDITS: (PHOTO) THE FIVE DEEPS EXPEDITION; (MAP) A. CUADRA/

SCIENCE

; (DATA) FIVE DEEPS EXHIBITION

Published by AAAS

on December 20, 2018^

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