Explorers to Use New Robotic Vehicles to Hunt for Life and Hydrothermal Vents on Arctic Seafloor


June 21, 2007

Scientists and engineers from the Woods Hole Oceanographic Institution
(WHOI) have just completed a successful test of new robotic vehicles designed for use beneath the ice of the Arctic Ocean. The
multidisciplinary research team will now use those vehicles to conduct
the first search for life on the seafloor of the world’s most isolated
ocean.

WHOI researchers have built two new autonomous underwater vehicles
(AUVs) and a new tethered, remote controlled sampling system
specifically for the difficult challenges of operations in the Arctic
ice. They hope to discover exotic seafloor life and submarine hot
springs in a region of the ocean that has been mostly cut off from
other ecosystems for at least 26 million years.

The 30-member research team will depart on July 1 from Longyearbyen, Svalbard, for a rare
expedition to study the Gakkel Ridge, the extension of the mid-ocean
ridge system which separates the North American tectonic plate from the
Eurasian plate beneath the Arctic Ocean.

The 40-day cruise on the
Oden—a 108-meter long (354-foot) icebreaker operated by the Swedish Maritime Administration—will
take researchers close to the geographic North Pole.

The research team for the Arctic Gakkel Vents Expedition (AGAVE)
includes specialists in each field of deep-sea exploration, with
scientists and engineers from the United States, Norway, Germany, Japan, and
Sweden.

WHOI geophysicist Robert Reves-Sohn will serve as chief
scientist. Fellow principal investigators include: Tim Shank, a
hydrothermal vent biologist from WHOI; Hanumant Singh, a WHOI engineer
and vehicle developer; marine chemist Henrietta Edmonds of the
University of Texas at Austin, who sailed on the last research
expedition to the Gakkel Ridge in 2001; Susan Humphris, a WHOI
geochemist who has surveyed dozens of hydrothermal vent sites around
the world; and Peter Winsor, a WHOI oceanographer who studies Arctic
Ocean circulation and its implications for climate.

Major funding for the expedition and for vehicle development was
provided by the National Science Foundation (NSF) and the National
Aeronautics and Space Administration (NASA).

“This is an exciting opportunity to explore and study a portion of
Earth’s surface that has been largely inaccessible to science,” said
Reves-Sohn. “Any biological habitats at hydrothermal vent fields along
the Gakkel Ridge have likely evolved in isolation for tens of millions
of years. We may have the opportunity to lay eyes on completely new
life forms that have been living in the abyss beneath the Arctic ice
pack.”

Most of the instrumentation that researchers would normally use to
study deep sea environments and organisms—such as the human occupied
submersible Alvin or tethered vehicles—cannot be safely operated in the
Arctic ice, which can easily crush most small vehicles. So researchers
asked Singh and colleagues to design and develop three new vehicles
from scratch.

During the July expedition, researchers will use the Puma AUV, or
“plume mapper,” to sniff out the chemical and temperature signals of
hot, mineral-rich fluids venting out of the ocean floor. Once Puma
finds the source of venting, Singh and colleagues will send down the
Jaguar AUV, which will use cameras and bottom-mapping sonar systems to
image the seafloor. Finally, the CAMPER towed vehicle will be lowered
to the seafloor to scoop or vacuum up rocks, sediments, and living
creatures.

During a 10-day engineering trial in May and June 2007, all three
vehicles were lowered through the Arctic ice and driven underwater,
while engineers simultaneously tested acoustic communications
techniques. The researchers were able to recover their vehicles from
beneath the ice, which can be risky in the midst of moving floes that
can quickly close the leads around an icebreaker.

“Anyone can deploy an AUV in the Arctic; the trick is getting it back,” said Singh, who will send his
vehicles to the seafloor for 10 to 24 hours at a time during the Gakkel
expedition. “In order to have a good day
with autonomous vehicles, the number of recoveries must equal the
number of launches.”

The Gakkel Ridge extends roughly 1,800 kilometers (1,100 miles) from
north of Greenland toward Siberia. It is both the deepest ocean
ridge—ranging from 3 to 5 kilometers (1.8 to 3 miles) beneath the ice
cap—and the slowest spreading tectonic plate boundary anywhere on
Earth. The ridge moves roughly one centimeter (1/3 inch) per year,
about 20 times slower than most other ridges.

At most mid-ocean ridges, Earth’s crust spreads apart, allowing hot
magma from the mantle to come up and form new ocean crust. The enormous
heat sparks chemical reactions between crustal rocks and the seawater
that seeps down into them.

These chemical reactions produce hot,
mineral-rich fluids that spew like geysers from seafloor vents, as well
as massive deposits of minerals, such as copper and zinc. These
hydrothermal fluids also contain chemicals that sustain rich
communities of unusual life forms, which thrive via chemosynthesis,
rather than photosynthesis.

Many geologists believed the Gakkel Ridge region would be too
geologically cold to produce hydrothermal vents. And yet during a 2001
expedition, researchers found signs of such venting in the Arctic.
Where there are vents, there may be unusual seafloor life forms.

“A few years ago, mid-ocean ridge and hydrothermal vent biologists came
together and asked: ‘Where are the key places in the world to go to
make big leaps in understanding biodiversity?’ The Gakkel Ridge was one
of the top places,” said Shank, who plans to study the genetics of
animals found during the expedition.

“The region has been mostly
separated from the Atlantic and Pacific oceans for millions of years,
so whatever lives there has since been evolving in relative
isolation—much the way animals in Australia did,” Shank added. “We know that deep-sea
Arctic fauna found away from vents are more than 70 percent different
from all others around the world. So at hydrothermal vents we are
likely to find completely new suites of species with never-before seen
adaptations.”

Some scientists—including program managers and scientists from the NASA
Astrobiology Program—have been keenly interested in the possibility
that Gakkel Ridge may harbor life forms and environmental conditions
consistent with primordial Earth or other watery planets.

“The origin of life discussion comes up because the rocks that are
exposed on this very slow spreading ridge are not volcanic, but instead
come directly from Earth’s mantle,” said Humphris. “The chemistry is
very much like the volcanism that occurred on the primordial Earth. If
you are thinking about origins of life, you’d like to have an area that
is the closest analog to what was happening on the early Earth.”

In July 2001, WHOI researchers were part of the Arctic Mid-Ocean Ridge
Expedition (AMORE) that produced the first detailed maps of the Gakkel
Ridge and made the unexpected discovery that the ridge is volcanically
active. Scientists also found that large sections of Earth’s
mantle appear to be deposited directly onto the seafloor along the Gakkel Ridge.

The Gakkel Ridge expedition will be covered live on the web, allowing
students, educators, and the general public to follow along with daily
dispatches from the Arctic Ocean. The Dive and Discover web site brings students and teachers along on
research field trips to read about science in action, while the Polar
Discovery
project uses photos and live phone
calls from the Oden to allow museum visitors and the public to see the
Arctic through the eyes of the explorers.

Support for the Gakkel Ridge
expedition and for underwater vehicle development has been provided by
the National Science Foundation’s Office of Polar Programs and Division
of Ocean Sciences; the NASA Astrobiology Program; the WHOI Deep Ocean
Exploration Institute; and the Gordon Center for Subsurface Sensing and
Imaging Systems, an NSF Engineering Research Center.

The Woods Hole Oceanographic Institution is a private, independent
organization in Falmouth, Mass., dedicated to marine research,
engineering, and higher education. Established in 1930 on a
recommendation from the National Academy of Sciences, its primary
mission is to understand the oceans and their interaction with the
Earth as a whole, and to communicate a basic understanding of the
ocean’s role in the changing global environment.