Chill Factors
Vescovo strategizing his
attempt to reach the bottom
of the Southern Ocean.scientist said after a particularly
hairy recovery, “I feel like I’m
watching a rescue every time.”
few afternoons before
Vescovo’s first official
dive in the Caribbean,
as camera operators
captured every con-
ceivable angle for a five-part
Discovery Channel series
that will document the quest,
Vescovo, chief scientist Alan
Jamieson, and Paul Henry Nar-
geolet, a retired French navy
submersible pilot, sat at a table
in Pressure Drop’s control room.
On the wall in front of them, a
large flat-screen displayed a 3D
map of the Puerto Rico Trench.
The area is a subduction zone,
a geologic spot where two tec-
tonic plates collide. Humankind
discovered it in 1876, when
Great Britain’s HMS Challenger
measured a depth of more than
7,000 meters by lowering a
hemp line until it went slack. In
1939, the USS Milwaukee iden-
tified the deepest part, on the
west end—which is why that
place is called the Milwaukee Deep. But more-modern
bathymetry (nautical speak for depth finding) from sur-
veys done by remote operating vehicles has rewritten that
history—a bit. According to Jamieson, their science team
identified a slightly lower point, just east of the area.
No human had been in the trench since the French
submersible Archimede dived it in 1964. The crew
reached 7,300 meters by accident. The story goes that
they weren’t looking for the deepest point; they’d wanted
to study escarpments, where the terrain juts steeply up-
ward, at the trench’s edge, and missed their landing spot.
Jamieson, a Scotsman who’s based at England’s New-
castle University, zoomed in on the map and pointed
out what a mission geologist suspected was the actual
deepest point: 8,376 meters. Over the next day or two,
Pressure Drop would cruise slowly over the area, using
sonar to scan the seafloor to verify its absolute bottom.
Mapping is a major component of the Five Deeps’ sci-
ence mission. While some trenches, such as the Mariana,
are fairly well- charted, others, including the South
Ocean’s South Sandwich Trench, are practically black
holes. Pressure Drop’s multibeam echo-sounding sonar—the most
sophisticated ever installed on a civilian vessel—would produce
detailed maps that are accurate to within just 2 meters, and should
advance the knowledge of even the better-known deeps. The crew
will make the data public and hand it over to an international orga-
nization of expert ocean cartographers known as GEBCO (General
Bathymetric Chart of the Oceans). “We are generating a baseline of
data on all five of the world’s major trenches, plus some other ones,”
Vescovo explained. “You can just imagine that the data could be used
for hundreds of years for seismology or cartography.”
Jamieson specializes in these so-called hadal zones of the
trenches—named, yes, for Hades. For the past two decades, he’s been
making special seafloor landers and joining expeditions to deploy
the portable science platforms in depths up to nearly 11,000 meters,
where they take photos and video and collect marine life samples via
onboard traps. So far, his teams have discovered “a super- giant arthro-
pod,” filmed the deepest-dwelling fish ever spotted in the Mariana
Trench, and amassed the world’s largest collection of hadal wildlife.
For Five Deeps, Jamieson worked with Triton to design three
different aluminum-framed landers that could work both alone and
in conjunction with Limiting Factor. The landers, which use the samePOPSCI.COM•FALL 2019 55