Press Release - January 15, 2003
Contact: Barbra Rodriguez, Media Relations,
College of Natural Sciences, 512-232-0675
Dr. Hedy Edmonds, Marine Science Institute, 361-749-6772,
Date: Jan. 15, 2003
Embargoed until 2 p.m. (ET), Wednesday, Jan. 15
Marine Scientists Discover First
Hydrothermal Vents in Arctic Ocean
AUSTIN, Texas-A geologically sluggish
region in the Arctic Ocean turns out to have hot spots of activity, according to
the first study of the Gakkel Ridge that runs near the North Pole. The study led
by a marine scientist at The University of Texas at Austin revealed that the
ridge where two tectonic plates meet has at least nine hydrothermal vents
releasing hot water as a result of volcanic activity.
"I never in my wildest dreams thought we'd see the extent of activity we saw in
the Arctic Ocean," said Dr. Hedy Edmonds, an assistant professor of marine
science and a hydrothermal vent expert.
Edmonds is lead author of an article about the Gakkel vents that will appear
Jan. 16 in the journal Nature. About half as many vents were expected to
be found along the Gakkel Ridge, an underwater volcanic mountain chain that
snakes for 1,100 miles from north of Greenland to Siberia.
of Gakkel Ridge area. The black dotted line is the ship's track for
July 28-Oct 3, 2001, and the yellow dots are the nine new vent sites. The North
Pole is at the center of the image.
The finding changes scientists' understanding of the way hydrothermal vents are
globally distributed. It also has implications for the way heat and chemicals
are exchanged between the Earth's mantle, the crust overlying the mantle, and
oceans, as well as for the way the Earth's crust forms when tectonic plates pull
Hydrothermal vents are often surrounded by rich underwater ecosystems, supported
by micro-organisms that survive on chemicals in the vents. Because the Gakkel
Ridge is isolated from its counterparts in other oceans, these new Arctic
ecosystems also likely contain previously unidentified organisms, which Edmonds
and other scientists hope to discover during future expeditions.
Hydrothermal vents develop along mid-ocean ridges when tectonic plates pull
apart, which allows molten material from the Earth's mantle to edge upward.
Water circulating through rocks that form the ocean floor absorbs heat from the
molten material, with the water escaping the Earth's interior in scalding hot
vents. The water can reach 350 degrees Celsius (662 degrees Fahrenheit), and
contains chemicals on which specialized microbes thrive.
The Gakkel Ridge, which is the slowest spreading of all mid-ocean ridges, was
expected to have about four vents based on a previous theory. The theory
postulated that slow-moving ridges should produce less molten material and heat
to fuel the formation of hydrothermal vents than their faster-spreading
counterparts. Based on the 2001 cruise results, hot spots of volcanic activity
likely make up for the low level of heat found along much of the ridge.
No one had previously looked for hydrothermal vents on the Gakkel Ridge because
of the time and expense involved in breaking surface ice to analyze the water
below. Edmonds searched the ridge for vents as an extra scientist on a nine-week
research cruise in summer 2001 on the U.S. Coast Guard cutter Healy. The
Healy and a companion German icebreaker were being used by geologists to
dredge rocks from the ocean floor to study how the Earth's crust forms.
Whenever the geologists on the Healy lowered their dredging equipment,
Edmonds and her colleagues attached a recording device to its steel cable to
test the water at different depths for increases in temperature or particles
that indicate a nearby hydrothermal vent. Vents release a mixture of chemicals,
including iron oxide particles, which are rare in surrounding ocean water. The
water from a vent initially stays together to form what is called a plume,
allowing its characteristics to be measured.
Edmonds obtained 145 water "profiles" and located nine hydrothermal vents to
within a few miles based on the signals of ocean temperatures and suspended
sediments as the Healy cruised along. She also pegged three other areas
as likely vent locations.
"Eighty-two percent of our water profiles had signatures of plumes in them,"
During the cruise, the geologists also mapped the ocean floor along the ridge,
which allowed Edmonds to confirm that the vents were located in geologic
features where hydrothermal vents would likely occur.
As further confirmation, she and colleague David Graham of Oregon State
University deployed a more specialized piece of equipment to measure additional
water characteristics associated with vent plumes. The device, called a CTD
(conductivity-temperature-depth) cast, was lowered into the ocean depths at six
locations along the ridge.
The CTD cast included 24 bottles for obtaining water samples at various depths.
Edmonds, Graham and British researchers Douglas Connelly and Chris German from
the Southampton Oceanography Centre, analyzed the samples after the cruise, and
discovered high concentrations of manganese and other vent-associated chemicals
at sites that matched Edmonds' earlier findings.
"With these additional measurements, we could say with certainty that this water
was coming from hydrothermal vents," Edmonds said.
Click here for a high-resolution, color map of the Gakkel
Ridge area or contact Barbra Rodriguez at