An expedition to the Arctic this summer by Woods Hole researchers will explore a part of the world still largely unseen by humans.
Adrianne Appel
Deep below the Arctic ice sits a vast volcanic ridge of mountains where numerous hydrothermal vents spew water as hot as 350 degrees Celsius. In hopes of finding new life forms there, Woods Hole scientists are embarking on a major expedition this summer to explore the underwater ridge.
Robert Reves-Sohn, a geophysicist with the Woods Hole Oceanographic Institute (WHOI), is leading a team of 40 scientists from 15 countries. In July, they will ride aboard a Swedish icebreaker headed towards the Gakkel Ridge, a long stretch of mountains, some as high as 1,000 meters, located on the floor of the Arctic Basin. The researchers will cut holes in the three-foot layer of ice and drop two newly built unmanned underwater vehicles into the water; one will find the vents, the other will travel 3,000 meters to the bottom to take pictures. “We don’t know what to expect,” said Reves-Sohn.
Oceanographers have previously discovered new species, like giant tube worms and strange kinds of shrimp, in hydrothermal vents in other parts of the world. But vents on the Arctic sea floor have remained largely unexplored because of the expense and challenge of working under the ice.
“The Gakkel Ridge vents are one last, large chunk of vents that haven’t been explored yet,” said Hanumant Singh, an oceanographic engineer with WHOI who designed the new vehicles. “It’s very exciting.”
The trip is part of International Polar Year, which begins tomorrow and continues until March of 2009. Organized by the International Council for Science and the World Meteorological Organization, this program includes more than 200 research and education projects on the Arctic and Antarctic and more than 1,000 scientists from around the globe.
Vent adventure
Scientists first found evidence for large numbers of vents along the Gakkel Ridge during a 2001 expedition, much to their surprise. “It blew us away,” said Reves-Sohn. The Gakkel Ridge has so little seismic activity that scientists thought it would have few vents. Since that startling find, Reves-Sohn has been itching to explore further.
In studying Gakkel Ridge rocks, researchers hope to find clues about how the Earth’s crust was formed. And they hope to learn more about the origins of life on Earth. ”Vents are where some people believe life began” billions of years ago because of the unique, mineral-rich conditions they produce, Singh said.
Gakkel Ridge was too deep for any of WHOI’s existing automated unmanned vehicles so Reves-Sohn teamed up with Singh and his graduate students to build two new ones, Jaguar and Puma. These vehicles can travel more than 2,000 meters deeper than earlier generations.
Puma and Jaguar, autonomous underwater vehicles, will scout out and take pictures of hydrothermal vents deep below the Arctic ice. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)
To find hydrothermal vents, the team will rely on a rough map based on data from the 2001 expedition showing the likely vent locations within 20 meters. They will then dispatch Puma.
With its unique array of chemical, pressure and temperature sensors, and a spectrometer onboard doing real-time analysis of water samples, Puma will “sniff out” mineral-rich plumes, following them to their source, the hydrothermal vents. The vehicle will steer and propel itself using battery-powered thrusters.
Once Puma locates a vent, it will be called back to the ship and Jaguar will be deployed.
Jaguar, which can dive deeper than Puma, will head to the bottom and hover near the vents. Once there, the 500-kilogram machine will turn on its lights and, using onboard cameras, take thousands of photographs. Reves-Sohn hopes the vehicles will each make 20 trips to the bottom during the 40-day expedition.
NASA chipped in $3 million for the construction of the vehicles because it views the expedition as a test run for a future NASA mission to one of Jupiter’s moons, Europa. Like Gakkel Ridge, Europa features volcanic activity beneath an icy surface.
The scientists will send another device, called Camper, weighing more than two tons, down to the ocean bottom. Tethered to the ship and equipped with a sort of shovel and vacuum hose, it will collect and suck up rocks and sand and any organisms it might find.
Most of the biological samples will be frozen and ferried back home for DNA testing and species identification, Reves-Sohn said.
The researchers have no idea what they might discover. “We just don’t know what’s going on under the Arctic Ocean. So it’s really exciting,” Singh said.