A recent survey along a midocean ridge beneath the Arctic icepack unveiled an unexpected abundance of hydrothermal activity. Besides casting doubt on current theories about where such vent systems can arise, the wayward vents could harbor ecosystems that are dramatically different from those found in other oceans.
Midocean ridges are seams where material wells up from Earth's interior to form new seafloor, explains Hedy Edmonds, a marine geochemist at the University of Texas' Marine Science Institute in Port Aransas. In 2001, she and other scientists used icebreakers to plow their way across the Arctic Ocean to make measurements along a 1,100-kilometer segment of the 1,800-km-long Gakkel Ridge. That little-explored midocean ridge, which is spreading slower than other known seams, runs within 350 km of the North Pole and lies at frigid depths between 4,500 and 5,000 meters.
Edmonds and her colleagues dredged the ocean floor for rocks at more than 150 sites along the ridg