A geologically sluggish region deep within the Arctic Ocean's frigid waters has turned out to be a surprisingly hot spot of hydrothermal activity.
Marine scientists on a maiden voyage to the remote area near the North Pole discovered at least nine submarine vents spewing sizzling fountains -- and portending the possible existence of exotic life -- along the Gakkel ridge, a barely budging mid-ocean mountain chain 3 miles below the Arctic icecap.
The researchers were caught off guard by the series of undersea vents belching steamy sprays from Earth's belly in the deepest, most remote portion of the global system of ocean ridges.
The scorching plumes cascaded at the crossroads of two tectonic plates, massive, continent-hoisting slabs of solid rock drifting into, past and away from each other like so many slow-motion bumper cars. Their boundaries often tremble with volcanic and earthquake rumblings.
Here, within the depths of the frozen sea nature has constructed a window into the center of the world and an escape hatch for molten rock trapped within. As the plates pull apart, magma bulges from the mantle melting in Earth's interior in a race toward the surface, the molten rock pushing apart the seafloor in a continuous construction of new ocean crust. The scorching goo, oozing upward, heats water circulating through rocks that carpet the seafloor. The searing liquid seeks its own release in scalding vents that can reach temperatures of 350 degrees Celsius (662 degrees Fahrenheit).
"I never in my wildest dreams thought we'd see the extent of activity we saw in the Arctic Ocean," said Henrietta Edmonds, assistant professor of marine science at the University of Texas, Austin, and lead author of the study, published in the Jan. 16 issue of the British journal Nature.
"We were so surprised, we thought there might be a problem with the instrument," recalled her colleague Charles Langmuir of the Department of Earth and Planetary Sciences at Harvard University in Cambridge, Mass., who is on sabbatical in Paris.
"On communicating with one of the world's experts on hydrothermal activity, he was at first convinced we had made some stupid error and that the data were not real," Langmuir told United Press International.
The disbelief grew out of expectations based on theories that correlate the amount of hydrothermal venting with the spreading rate of a ridge. Prior to the 9-week international expedition to one of the least-explored corners of the world in the summer of 2001, most scientists had anticipated finding scant evidence for deep-sea hot springs along Earth's slowest-moving mid-ocean ridge.
Gakkel ridge, which snakes for 1,100 miles from far north of Greenland to the Laptev Sea off the coast of Siberia, creeps along at less than 1 centimeter a year. As a comparison, the bulging ridges in the Pacific Ocean widen 20 times faster.
"Most people predicted we would find little or no hydrothermal activity on the Gakkel ridge," Langmuir told UPI. "This expectation was sufficiently strong that hydrothermal work was not actually funded in our proposal -- it was 'bootlegged' as a side project."
Peter Michael of the University of Tulsa, the chief scientist on the U.S. research icebreaker Healy, which was making its maiden voyage, arranged for hydrothermal data to be collected and for Edmonds, a vent expert, to come along on the off chance she might find something.
In beating the odds, she and colleagues aboard Healy and the companion German research vessel Polarstern discovered multiple signs of deep-sea hot springs that often host oases of life on the ocean floor.
"To find so much venting with such large plumes associated with it was completely unexpected," said Maya Tolstoy, associate research scientist at the Lamont-Doherty Earth Observatory at Columbia University in Palisades, N.Y. She was the first scientist to observe a volcanic eruption on the ultraslow-spreading mid-ocean ridge, an event she described in the Feb. 15, 2001, issue of Nature.
"It just goes to show how little we still know about the seafloor, and how much of it remains unexplored."
The findings alter scientists' understanding of the way hydrothermal vents are globally distributed. They also shed new light on the process by which heat and chemicals are exchanged between the Earth's mantle, the crust overlying the mantle and the oceans as well as on the mechanisms that cause Earth's crust to form when tectonic plates slowly disengage.
"(The study) will make us change our way of thinking about this ridge system -- it no longer can be seen as a cold and likely barren site, and instead it seems like a dynamic, enticing place to go explore," Tolstoy told UPI. "What is more intriguing is what kind of biology might exist down there, since the environment is both isolated and very different from previous places we have looked."
Hydrothermal vents often attract rich underwater ecosystems, supported by microorganisms that survive on the hot spring chemicals. Because the Gakkel ridge is isolated from the rest of the world's ocean ridges, it likely harbors previously unidentified organisms, which Edmonds and other scientists hope to uncover in future expeditions.
"This article is ... an exciting illustration that deep-sea hydrothermal sources of new organisms with potential applications in biotechnology may be more abundant, and the organisms more diverse, than previously thought," Doug Clark, professor of biochemical engineering at the University of California, Berkeley, told UPI.
The vents also may hold clues to life's beginnings.
"Hydrothermal vents are likely locations for the origin of life in the early Earth because they are sources of energy and nutrients, they support life in the absence of sunlight, and they are protected from the ultraviolet rays and meteorite impacts that would have continually sterilized the early Earth," Langmuir told UPI.
"Hydothermal vents are also ... the ocean's 'kidneys.' They are an essential ingredient in the chemical balance of seawater, which without them would quickly become unsuitable for life as we know it."
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 on an expedition with the primary purpose of dredging rocks from the ocean floor to study how the Earth's crust forms.
Whenever the geologists aboard the Healy lowered their 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 would indicate a nearby hydrothermal vent.
In this fashion, Edmonds obtained 145 water "profiles," located nine hydrothermal vents to within a few miles and pegged three other areas as likely hot springs sites.
During the cruise, the geologists mapped the ocean floor along the ridge, allowing Edmonds to confirm the vents' location.
The findings point to how much humans still have to learn about their home planet, scientists said.
"The seafloor is still more poorly known that the surfaces of the moon, Venus and Mars. Great discoveries are still to be made there," Langmuir noted. "The ocean ridge system, hidden from view and unknown to most of humankind, is an essential part of the Earth system on which the successful functioning of the whole planet depends. We humans, life and the Earth are all parts of an interconnected system."
