http://oceanusmag.whoi.edu/v42n2/sohn.html

Unique Vehicles for a Unique Environment New autonomous robots will pierce an ice-covered ocean and explore the Arctic abyss

By Robert Reves-Sohn, Associate Scientist, Geology and Geophysics Department, Woods Hole Oceanographic Institution magine you have inherited a magnificent medieval cas- Itle. You wander its corridors, climbing spiral staircases to hidden towers, delving purposefully into subterranean caverns, and delighting in the details of its architecture, history, and artistic treasures. Over time you come to realize there is a great North Wing Puma and Jaguar are autonomous that has long been sealed off from the rest of the castle. underwater vehicles (AUVs) designed You’ve found old documents in the library describ- to overcome the technical challenges ing construction of the North Wing, and it appears as that now preclude under-ice operations though it was built using rare materials that are not in the Arctic Ocean. They will home in found anywhere else in the castle. As best as you can to an acoustic beacon and latch onto a tell the castle’s main thermostat is inside the North Puma wire suspended from a hole in the ice. Wing, which adds some urgency because lately Puma has sonars and sensors to search the castle seems to be getting inexplicably wide areas and detect temperature, warmer. And, perhaps most intriguing, chemical, or turbidity signals from recent evidence suggests that some- hydrothermal vent plumes (the green thing—perhaps even something lasers detect particulates in the water). unusual—might actually be Puma can track the plume back to its living in there. seafloor source, where Jaguar then will Even so, it might be be deployed to hover with camera and more accurate to con- lighting systems, high-resolution sonar, fess that you’ve just got and a manipulator arm for close-up to gain entrance to the imaging, mapping, and sampling. North Wing—because not being able to enter rooms in your own house is unbearable.

Jaguar E. Paul Oberlander, WHOI Graphic Services Oberlander, E. Paul

Woods Hole Oceanographic Institution 1 Finding a way in tion, possibly making the Arctic a sort of You come to realize, however, that marine equivalent of Australia. (See “The you’re not the first to try. Numerous ������ Evolutionary Puzzle of Seafloor Life,” intrepid individuals have dedicated page 78). themselves to the pursuit over the years, �������

their stories comprising a veritable tome G A K K E L R I D G E A 21st-century voyage of discovery of frustration and failure. And why? In 2001,������ Woods Hole Oceanographic Because the North Wing is hidden under Institution (WHOI)������ scientist Henry Dick a moat of water more than two miles Arctic was part of a team that conducted the deep, which, in turn, is covered by a per- Ocean most detailed exploration to date of the manent layer of ice. Basin Gakkel Ridge, which transects the eastern Moreover, it is so far north that the Arctic Basin and is perhaps the most enig-

compasses and gyroscopes typically used������ ���������� matic tectonic plate boundary on Earth.

Emerging Technology Emerging for navigation are essentially useless. The������ Like all mid-ocean ridges, the Gakkel tools required to get through ice and into Ridge is an undersea volcanic mountain the abyss to explore the North Wing can- chain where magma erupts to create new not be bought at any price. You will have ������ ocean crust that spreads out on both sides to make them yourself. of the ridge. It was thought to be spreading

You have probably guessed by now that WHOI Graphic Services Doucette, Jayne so slowly, however, that it would have little the castle in this mental exercise is Earth, An expedition in 2007 is planned to search volcanic and hydrothermal activity on it. and the North Wing is the vast, ice-cov- for, map, and sample hydrothermal vents for But Dick and colleagues found tantaliz- ered Arctic Ocean Basin. If the old adage the fi rst time beneath the ice-covered Arctic ing clues of active volcanism and ubiqui- is true that we know more about the sur- Ocean, along the Gakkel Ridge. tous hydrothermal venting on the Gakkel face of our neighboring planets than we Ridge. What’s more, they gathered evi- do about Earth’s ocean basins (and it is), oceans, the evolution of life, and our plan- dence that seafloor spreading on the Gak- then nowhere is it more true than the Arc- et’s susceptibility to climate change. kel Ridge occurs in a fundamentally dif- tic Basin. ferent way compared to other previously An unexplored frontier explored ridges. (See “Earth’s Complex A blank spot on the map of Earth For climatologists and physical ocean- Complexion,” page 36.) Deep-sea research is hard enough as ographers, it is often said that the Arctic is a Dick and colleagues recovered rocks it is. But cover the ocean you’re trying to canary in the environmental coal mine. In from the Gakkel Ridge composed of mate- explore with a permanent ice cap, limit a warming world, the Arctic’s delicately bal- rials that normally reside in the mantle your available field season to a few months anced ocean circulation and sea ice appears deep within Earth’s interior, and that are that are not too cold and dark, and factor vulnerable to disruptions that could have rarely found on Earth’s surface. These in a generally inaccessible location at the dramatic impacts on Earth’s oceans and cli- rocks are perhaps the closest modern ana- very top of the world, and you can begin mate. Thus, climate change drives a large logues to the kind of volcanic rocks that to appreciate why we know so little about percentage of Arctic research. erupted billions of years ago in the early the Arctic Basin. But the Arctic Basin is so unknown stages of Earth’s history. They have a dis- In fact, were it not for a few Rus- and unique, it probably holds more undis- tinct chemistry that affects their interac- sian and American scientists whiling the covered scientific treasures than any other tion with seawater circulating through months away in camps on drifting ice ocean basin on Earth. Perhaps the hardest hydrothermal vent systems. (See “The floes, we would know almost nothing at all challenge is deciding which fundamental Remarkable Diversity of Seafloor Vents,” about the earth’s great North Wing. (Actu- scientific questions to attack first. page 60.) These chemical reactions release ally, U.S. and Soviet navies also gathered For marine biologists, for example, the exceptionally large amounts of chemi- data about the Arctic during the heyday Arctic represents a potential gold mine. cal “food” for the kinds of evolutionarily of Cold War submarine warfare, but this About 65 million years ago, the Arc- ancient microbes that reside at the roots information is generally classified.) tic Ocean basin became enclosed, with of the Tree of Life. (See “Is Life Thriving The human spirit cannot abide a puzzle no deepwater connections to any other Deep Beneath the Seafloor?” page 72.) with a missing piece. But this is especially ocean basin on Earth. Species and bio- The hydrothermal vent fields on the Gak- so when the missing piece could fill in logical communities in the Arctic Ocean kel Ridge could therefore provide a means crucial details about the origin of Earth’s may have developed and evolved in isola- to study hydrothermal activity on an early

2 Oceanus Magazine • Vol. 42, No.2 • 2004 Earth, and possibly even provide clues to can be deployed and recovered through a AUVs (named Jaguar), will be deployed. the origin of life on this planet. small hole in the ice. These will be able to hover in place, and Life is easier if AUVs can simply pop equipped with camera and lighting sys- Many questions, little data up on the ocean surface for recovery, but tems, high-resolution sonar, and a manip- Scientists only began to get their first Arctic pack ice adds complications. APO- ulator arm with storage canisters, they will detailed look at the Arctic seafloor between GEE was designed with critical acoustic be used for mapping, imaging, and sam- 1995 and 1999, when the U.S. Navy and the navigation and control systems that allow pling at vent sites. National Science Foundation (NSF) teamed it to navigate to a homing beacon, latch Fully autonomous methods have never up to use Navy nuclear submarines for itself to a wire suspended from a hole been used to find and image, not to men- unclassified scientific investigations. in the ice, and ultimately be recovered tion obtain samples from, vent fields in We still have almost no data from by scientists on an icebreaker or an ice any ocean, not to mention an ice-covered most of the mountain chains in the Arctic camp. Without this essential capability, one. The technical challenges are serious Basin, so we’re still guessing about their an AUV in the Arctic would almost cer- and legion, but they are worthy of a cut- composition, age, and origin. Yet, the tainly be lost. ting-edge oceanographic institution such sparse evidence we do have suggests that as WHOI. We are of necessity drawing the Arctic Basin did not form the same To the Arctic and beyond? on the expertise, inspiration, and creativ- way other ocean basins did, and that it We conducted our last set of sea tri- ity of dozens of experts hailing from every may have the oldest extant ocean crust in als with APOGEE in 2003. Now, we have department within the institution. the world. begun to build the next generation of Arc- There is no denying that we are That’s why we dream about retrieving tic vehicles—under a joint grant (with the attempting an ambitious project that faces data from beneath the Arctic ice cap, and University of Maryland’s Space Systems stiff technical challenges, but this ener- why we have begun to harness 21st-century Lab) from the Astrobiology Science and gizes and motivates us. Ultimately, we will technology to make those dreams come Technology for Exploring Planets program succeed or fail based on the talent and true. Nuclear subs are far too expensive to of the National Aeronautics and Space dedication of the scientists, engineers, and build and operate, and besides, they are Administration. technicians who are conceiving, designing, crushed like tin cans at full Arctic seafloor Our mission will be to use AUVs to and fabricating the new instrumentation depths. Instead, in our quaint New England find, map, and sample hydrothermal we will take to the Arctic. Anyone who village of Woods Hole, we are developing vent fields on the Gakkel Ridge. We will knows the people on our team would be autonomous underwater vehicles (AUVs) develop instrumentation that will guide reluctant to bet against us. and other advanced deep-submergence future efforts to search for life on Europa, technologies that can open up the Arctic a Galilean moon of Jupiter, which may Robert Reves-Sohn is Basin to scientific investigation. have two necessary ingredients for life: an Associate Scientist active volcanism and an ocean—albeit an in the Geology and Overcoming the ice barrier ice-covered one. Geophysics Depart- ment at Woods Hole Though many scientists dream of get- The mission will also allow us to study Oceanographic In- ting beneath the ice to study the Arctic Arctic vent fields for the first time. We stitution. He decided Basin, the long-standing commitment to will use a small group of purpose-built to pursue a career in ocean technology and instrumentation at AUVs, each with different characteristics geophysics when, as a grad student at Scripps Institution of Oceanography, he read the in- WHOI gives scientists here the opportu- and equipped with state-of-the-art sen- struction sheet on “How to Prepare a Perfectly nity to turn dreams into reality. We for- sor systems. They will work in concert Putrid Poster” for his first American Geophysi- mally began a program to develop AUVs to study Arctic vent fields. For example, cal Union meeting back in 1992. The official instructions suggested that the presenter eschew specifically for under-ice operations in a “bloodhound” AUV (named Puma, for logical arrangement of the material, use illeg- the Arctic in January 2000 when the NSF Plume Mapper) will be equipped with ible fonts, and, most importantly, “consume Office of Polar Programs awarded WHOI sensors that can detect tiny telltale tem- copious quantities of beer” before presenting the poster. He immediately realized he had found a grant to design, fabricate, and test a perature, chemical, or turbidity signals the peer group he had been looking for. His prototype vehicle called APOGEE, the in the water. It will survey a wide area to interest in AUVs is a natural outgrowth of his Autonomous Polar Geophysical Explorer. “sniff out” one of the hydrothermal vent innate tendencies as a technophile, although the The objective was to develop a swimming plumes that Henry Dick got whiffs of in notion of using AUVs to get under the Arctic ice pack came to him while playing with a Sesame robot that can carry a variety of scien- 2001 and follow it back to its vent field Street submarine and giving his (then) newborn tific sensors to explore the most inacces- source on the seafloor. (now 8-year-old) daughter a bath. sible regions of the Arctic Basin, and that Once a vent is found, “hummingbird”

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