Scientists and engineers from the Woods Hole Oceanographic
Institution (WHOI) have just completed a successful test of new robotic
underwater 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.
|Researchers will use two new autonomous underwater vehicles (AUVs) in tandem to locate hydrothermal vent sites on the seafloor of the Arctic Ocean. Puma will "sniff out" the source of hot, mineral-rich fluids venting from the seafloor, and Jaguar will use cameras and bottom-mapping sonar systems to image the location. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)
|Enlarge ImageMap of the Arctic Ocean, looking down on the North Pole, shows the Gakkel Ridge, Nansen Basin, and the proposed cruise track of the Oden. (Data from the International Bathymetric Chart of the Arctic Ocean and the National Geophysical Data Center; with graphic enhancements by Jack Cook, Woods Hole Oceanographic Institution)
|Enlarge ImageThe icebreaker Oden, operated by the Swedish Maritime Administration, will carry 30 researchers from Svalbard to the Gakkel Ridge (roughly 85 N latitude) and back to Norway. (Photo by Hanumant Singh, Woods Hole Oceanographic Institution)
|Enlarge ImageThe Puma AUV uses sonar, lasers, and chemical sensors to search wide areas near the ocean floor to detect the telltale signals from hydrothermal vent plumes. (Photo by Hanumant Singh, Woods Hole Oceanographic Institution)
|Enlarge ImageThe Camera Sampler, or CAMPER, towed vehicle is lowered over the stern of the icebreaker Oden during engineering tests in June 2007 in the Arctic Ocean. (Photo by Hanumant Singh, Woods Hole Oceanographic Institution)
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 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.
cruise on the Odena 108-meter (354-foot) long icebreaker
operated by the Swedish Maritime Administrationwill 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,
Germany, Japan, Norway, 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 currents and their 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 organismssuch as the human occupied
submersible Alvin or tethered vehiclescannot 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. (Click here to view an MP4 animation of the sequence.)
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
“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
during the Gakkel expedition. “The trick is getting it back. In order to have a
good day with an autonomous vehicle, 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 ridgeranging from
3 to 5 kilometers (1.8 to 3 miles) beneath the ice capand 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 isolationmuch 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
Some scientistsincluding program managers and scientists
from the NASA Astrobiology Programhave 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 recently also found that large sections of Earth’s mantle are
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 (www.divediscover.whoi.edu) brings students and teachers
along on research field trips to read about science in action, while the Polar
Discovery project (polardiscovery.whoi.edu) 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