A visit to one of Earth's
By Ned Rozell
November 07, 2007
People wait years for permits to raft the Grand Canyon. Michelle
Ridgway just visited a much larger canyon in Alaska, one that
most people will never hear about.
Zhemchug Canyon, 20 percent longer and deeper than Grand Canyon,
is a T-shaped cut in the sea floor beneath the gray waters of
the Bering Sea. On a recent Greenpeace-sponsored expedition,
Ridgway, a marine ecologist and consultant from Juneau, descended
into the canyon alone in a tiny submarine.
"I'd been through the Grand Canyon the year before and was
expecting a real similar experience," Ridgway said. "But
I was humbled. (Zhemchug Canyon is) enormous."
The ancient Yukon River may have contributed to the vastness
of Zhemchug Canyon, according to a theory first presented by
David Scholl and the late David Hopkins. During the last Ice
Age, when more of the world's oceans were locked up in glacier
ice, the Yukon flowed a few hundred miles farther southwest,
carving at its mouth the vast gorge that is now Zhemchug Canyon,
which lies about 170 miles northwest of St. Paul Island.
A tiny golden king
crab living within an orange sponge in Zhemchug Canyon.
Photo courtesy Warshaw/Greenpeace
Named after a Soviet research ship and a word meaning "pearl,"
Zhemchug Canyon cuts into the ocean floor at the western edge
of the Continental Shelf, "one of the flattest and smoothest
places on the planet," Dan O'Neill wrote in his book, The
Last Giant of Beringia. "Its slope, at no more than three
or four inches per mile, is almost unmeasurable."
From that undersea plain, Zhemchug Canyon plunges more than 8,500
feet into the Aleutian Basin. Michelle Ridgway piloted an eight-foot
long submarine into that abyss.
As she descended and daylight began to fade, Ridgway noticed
Dall's porpoises darting by her tiny craft, which featured a
titanium body and pressure-resistant acrylic dome. When she reached
300 feet, the porpoises shot down to her for a final glance before
they headed back to the surface, and then she was the only mammal
she knew of. She kept dropping until she reached a bench at 1,757
feet. There, she entered a world of tangerine-colored life forms,
including fish, corals, crabs and sponges illuminated by the
submarine's blazing halide beams.
"They ranged from pale gold to a brick red," she said
of the creatures in the dark world of the canyon. "It was
That peculiar color scheme intrigues Ridgway, as does the variety
of life in Zhemchug Canyon.
A map of the sea floor
off western Alaska showing Zhemchug Canyon, one of the largest
canyons in the world. The map comes from a 1970 paper in Marine
Geology by D. Scholl, E. Buffington, D. Hopkins and T. Alpha.
"We didn't expect such a diversity of sponges and corals,"
she said. "And a huge surprise to me is what might be a
correction to what we assumed about zooplankton distribution
in the water column. The entire water column was teeming with
a very dense aggregation of zooplankton."
A common theory is that the tiny creatures that make up the plankton
kingdom hang out nearer to the surface, and the bottom-feeding
fish, sponges, and other life forms survive on the leavings of
organisms higher up. That might not be true, at least in Zhemchug
"It's rich and living at every depth we examined,"
Having descended only one-fifth of the canyon's 8,500 feet, Ridgway
wants to probe deeper into the great gorge beneath the Bering
"Next year, I hope to get in a submarine rated to 1,300
meters (about 4,200 feet)," she said. "And we hope
to have an ROV (remotely operated vehicle) that can go to the
bottom next time."
An adventurous soul, Ridgway also hopes she can someday launch
an expedition in a submarine equipped to get to the bottom of
one of the deepest canyons on the planet. Who knows what unique
forms of life await her visit?
"I'd love to go," she said.
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Ned Rozell [email@example.com]
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