Three new robotic vehicles designed by researchers at Woods Hole Oceanographic Institution will embark on an expedition next month to search for life on the Arctic Ocean floor.
The vehicles — two autonomous underwater vehicles (AUVs) and a tethered, remote-controlled sampling system — were designed specifically for the challenges of operating in Arctic ice, which can easily crush most small vehicles.
“Anyone can deploy an AUV in the Arctic; the trick is getting it back,” said Hanumant Singh, the lead Woods Hole engineer and vehicle developer on the project. “In order to have a good day with autonomous vehicles, the number of recoveries must equal the number of launches.”
Icy Depths
The vehicles were successfully tested in May and June with trials in which they were lowered through the Arctic ice and driven underwater, while engineers simultaneously tested acoustic communications techniques. Such maneuvers can be risky because of moving floes that can quickly close the openings in ice around an icebreaker, but the researchers were able to recover their vehicles from beneath the ice.
On July 1, a 30-member research team will depart with the new vehicles from Longyearbyen, Svalbard, for a rare expedition to study the Gakkel Ridge, the extension of the mid-ocean ridge system that separates the North American tectonic plate from the Eurasian plate beneath the Arctic Ocean.
The Gakkel Ridge holds particular interest for scientists because it is believed to have been mostly cut off from other ecosystems for at least 26 million years. Scientists on the project hope to discover exotic ocean-floor life and submarine hot springs in the region.
40 Days
The 40-day expedition, which was funded by the National Science Foundation and NASA, will be conducted on the Oden, a 354-foot icebreaker operated by the Swedish Maritime Administration. It will take researchers close to the geographic North Pole.
The research team includes scientists and engineers from the United States, Norway, Germany, Japan and Sweden.
“This is an exciting opportunity to explore and study a portion of Earth’s surface that has been largely inaccessible to science,” said Woods Hole geophysicist Robert Reves-Sohn, who is the chief scientist on the project.
“Any biological habitats at hydrothermal vent fields along the Gakkel Ridge have likely evolved in isolation for tens of millions of years,” he said. “We may have the opportunity to lay eyes on completely new life forms that have been living in the abyss beneath the Arctic ice pack.”
Harsh Conditions
In order to conduct the planned investigations, the new vehicles will have to work under extremely harsh, icy conditions, and they will have to be able to remain on the ocean floor for 10 to 24 hours at a time — something most robotic vehicles used for open ocean exploration could not handle.
“Most robots are designed to be slightly buoyant, so that if something goes wrong, you can shut them down and they will float to the surface,” Singh told TechNewsWorld. “On this expedition, that wouldn’t work too well, because they would come up under ice.”
The Gakkel Ridge
The Gakkel Ridge extends roughly 1,100 miles from north of Greenland toward Siberia. It is not only the deepest ocean ridge but also the slowest-spreading tectonic plate boundary anywhere on Earth, moving just one centimeter per year.
Until recently, many geologists believed the region would be too cold to produce hydrothermal vents, which are often accompanied by life. During a 2001 expedition, however, researchers found signs of such venting in the Arctic, suggesting unusual life forms may be nearby.
The region has also been identified as one that may lend insights into astrobiology and early life on Earth because of the possibility that it may harbor life forms and environmental conditions like those on primordial Earth or other watery planets.
Other Planets
In fact, the Gakkel Ridge expedition received funding from NASA because the region’s conditions are similar to those on Europa, one of Jupiter’s moons, Singh explained.
“If you look at Europa, it has a hot volcanic core, and is covered on the surface with ice,” he said. “We don’t know how much ocean is in between the ice and the hot core, but if there is ocean, there’s also the possibility that it might be a very good place to look for life in the solar system outside of Earth.”
Singh’s vehicles and their ability to operate under ice are, in a sense, a sort of early “test-drive” for similar expeditions — some day in the future — on a planet like Europa.
Thicker Than Thick
Of course, that’s still pretty far off. In the Arctic, the ice is a few meters thick; on Europa, “it’s more like 10 kilometers thick — or more,” Steven D’Hondt, professor of oceanography at the University of Rhode Island, told TechNewsWorld.
Whether the hydrothermal vent systems in the Arctic prove to be significantly different from those in other regions of the Earth also remains to be seen.
Such vent systems are fueled primarily by reduced sulfur venting out and reacting with oxygen and nitrate in the sea water. “Deep ocean everywhere has oxygen and nitrogen, so if these Arctic vents are just pumping out sulfide, they will probably be much like vents anywhere else,” D’Hondt said.
How Different Is Different?
Given too that different portions of ocean are in communication with each other, it’s possible that any life around these hydrothermal vents will be much like those found elsewhere, he said.
“When we core sediments in cold regions of ocean, we invariably isolate hydrothermal bacteria,” he explained. “They are not native — they’ve have been dispersed there. So we might expect to find similar microorganisms in the Arctic as well.”
Genetic tests will likely be one key to determining how different — or similar — any Arctic life found actually is from that on other parts of the planet.
A Win-Win
“Life found in this tectonically benign environment likely evolved in isolation and could be quite distinct from microbial communities hosted by hydrothermal vents elsewhere,” Michael Mumma, principal investigator for the NASA Astrobiology Institute’s Goddard Space Flight Center team, told TechNewsWorld.
“The potential for obtaining new insights is clearly very high, but their significance will be revealed only after genomic sequencing of extracted samples is complete and the new results are compared with those obtained from other sites,” Mumma said.
Yet even if researchers on the expedition don’t find unique life, that in itself will be an interesting finding, D’Hondt added, and would provide insight into how ecosystems are distributed.
“Either way, they win,” he concluded, “and operating near the North Pole is just a fundamentally cool thing to do.”
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