Embargoed until 1 P.M., EST
NSF PR 01-93 - November 28, 2001
Healy Researchers Make a Series of Striking
Discoveries About Arctic Ocean
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Video Available:
Researchers explain historical significance
of Healy's maiden scientific voyage.
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slide show, Part 1
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slide show, Part 2
A cross-section of an ocean ridge.
A larger version
is here.
Graphic credit: Kirk Woellert/NSF
A high
resolution version is here for downloading.
Researchers pore over a map of the Gakkel
Ridge
A larger
version is here.
NSF Photo: Henry Dick,
Woods Hole Oceanographic Institution
Healy and Polarstern navigating the ice
together.
A larger
version is here.
NSF Photo: Henry Dick,
Woods Hole Oceanographic Institution
The USCGC Healy in Arctic ice.
A larger
version is here.
NSF Photo: Henry Dick,
Woods Hole Oceanographic Institution
The USCGC Healy in Arctic ice.
A larger
version is here.
NSF Photo: Henry Dick,
Woods Hole Oceanographic Institution
The German research vessel Polarstern
which sailed with Healy on the
Arctic Mid-Ocean Ridge Expedition
A larger
version is here.
NSF Photo: Henry Dick,
Woods Hole Oceanographic Institution
Researchers work with a deck crane on
Healy.
A larger
version is here.
NSF Photo: Henry Dick,
Woods Hole Oceanographic Institution |
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Contrary to their expectations, scientists on a research
cruise to the Arctic Ocean have found evidence that
the Gakkel Ridge, the world's slowest spreading mid-ocean
ridge, may be very volcanically active. They also
believe that conditions in a field of undersea vents,
known as "black smokers," could support previously
unknown species of marine life.
The findings were among a range of discoveries made
by researchers aboard the US Coast Guard Cutter Healy,
an icebreaker equipped for science, and a companion
German research vessel, the Polarstern, in
late August, early in a nine-week cruise to the Gakkel
Ridge, Earth's least volcanically active mid-ocean
ridge.
"We accomplished easily a factor of two more than we
planned," said Peter Michael, of the University of
Tulsa, the U.S. chief scientist on the National Science
Foundation (NSF) funded Arctic Mid-Ocean Ridge Expedition
(AMORE).
Michael and other AMORE researchers discussed their
findings Nov. 28 at a news conference at the National
Press Club in Washington, D.C.
Among other important milestones from the cruise, scientists
discovered an as yet unexplained "discontinuity" of
volcanic activity along the Gakkel Ridge. Because
the southern end of the ridge is spreading relatively
quickly and the northern end extremely slowly, the
researchers expected volcanic activity to gradually
die out as they sailed north. Instead, there were
irregular pockets of activity as the cruise moved
northwards.
They said they were also pleased to discover that they
were able to map the ridge in great detail from the
Healy because the vessel was much quieter when
breaking ice than expected.
"Our maps show that this ridge is tectonically very
different than other ridges, the rift valley is close
to a mile deeper with many enormous long-lived faults",
explained Henry Dick, an expedition co-chief scientist
from the Woods Hole Oceanographic Institution. "This
likely accounts for why so many hydrothermal plumes
were found here."
Prior to the AMORE cruise most scientists expected
little recent volcanic activity and scant evidence
for hydrothermal vents, the deep-sea hot springs that
host oases of life on the deep seafloor. Instead,
sampling sites revealed abundant fresh lava and multiple
signs of hydrothermal activity.
Most surprisingly, a dredge team, led by Jeffrey Standish,
a graduate student at the Woods Hole Oceanographic
Institution, recovered fresh sulfides that apparently
are part of "black smoker" chimneys, the most striking
manifestation of hydrothermal activity. The find was
verified by a camera and sensor package lowered to
the seafloor from the Polarstern that showed
intact sulfide chimneys and recorded warm water vents.
The expedition proposed the name "Aurora" for the
vent field.
"We found more hydrothermal activity on this cruise
than in 20 years of exploration on the mid-Atlantic
Ridge," said Charles Langmuir, co-chief scientist
on Healy from Lamont-Doherty Earth Observatory
(LDEO) at Columbia University.
While the heated water from the hydrothermal vents
does not significantly affect ocean temperatures,
the vents have attracted the attention of both biologists
and geologists. Hydrothermal vents on mid-ocean ridges
in the world's oceans provide chemical energy that
supports exotic life forms and large ecosystems far
removed from the Earth's sunlit surface, where photosynthesis
forms the base of the food chain. "Our discovery of
these signals clearly show that hydrothermal vents
similar to those present on faster spreading mid-ocean
ridges are present in abundance here, too," said AMORE
researcher Henrietta Edmonds of the University of
Texas.
AMORE mapped and sampled the Gakkel Ridge which, extends
1100 miles from north of Greenland to Siberia, all
of it beneath the Arctic ice cap. The ridge is the
deepest and most remote portion of the global mid-ocean
ridge system, where new ocean crust is continuously
created as seafloor spreading takes place through
volcanic activity. Many theories about seafloor spreading
can be tested only on a slow-spreading ridge like
the Gakkel. Geologists, oceanographers and biologists
on both ships recovered numerous samples of rocks,
mud, water as well as organisms from the seafloor
that they will analyze in their labs.
The Arctic Ocean's isolation from major ocean basins
has led scientists to debate whether ecosystems on
Gakkel Ridge would more resemble those from the Atlantic
or Pacific Oceans, or whether they would have evolved
separately. "These exciting discoveries on Gakkel
Ridge pave the way for future expeditions that will
map the vents and may discover completely new organisms"
Michael said.
The AMORE research was the first full science expedition
for HEALY after an extensive four-month program of
icebreaking and science equipment testing in the Arctic
last year.
Editors: For B-roll, contact Dena Headlee (703)
292-8070/dheadlee@nsf.gov
The news conference will be webcast at http://www.connectLive.com/events/nsf
For more information from Columbia University about
the AMORE cruise, including the ship's log, see http://www.earthscape.org/frames/news2frame.html
See also:
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