Four decades ago, Paul Dayton, a gutsy benthic ecologist, plunged into the -2° C waters below the Antarctic sea ice, sinking as far as 61 meters to study this unique ecosystem of sponges, colorful sea stars, and other bottom crawlers. "I remember being so cold and miserable and crying daily," Dayton recalls from the warmth of the Scripps Institute of Oceanography in San Diego, where he has been a professor for 38 years. "But the dives themselves were so amazing and wonderful."
Dayton's dives were also extremely dangerous, at least in the eyes of the National Science Foundation, which oversees Antarctica's American base. By the early 1970s, NSF instituted rules banning divers from swimming below 41 meters. Much of Dayton's work—including transects he monitored annually to understand animal distributions and growth rates, and cages he planted to study starfish predation on sponges—was suddenly off limits.
Fast forward two scientific generations to Stacy Kim. Now a professor at Moss Landing Marine Laboratories south of Monterey, Calif., Kim was once a student of one of Dayton's students, and heard tales of Dayton's abandoned work."There [are] these huge data sets that, unless someone's carrying on the torch, [are] just becoming lost," says Kim. "A 40-year perspective on benthic ecology, especially in arctic regions, that's just an unheard of data set."
Ecological data from this part of the world's oceans is especially valuable because, until recently, the area was relatively undisturbed by human forces. This isolation is disappearing, though, as fisheries begin casting their nets for Antarctic cod, tearing up the sea floor and changing the predator-prey balance in the process. Because Dayton's experiments were initiated decades ago, Kim says, they would provide a priceless timeline of the changes in benthic populations, and how those changes have been impacted by global warming.
During a soak in the hot tub one night in 2003, Kim's future husband, engineer Bob Zook, asked her if there was any tool that would make her Antarctic research easier. He listened, then cobbled together model airplane motors, security cameras and cell phone power sources to create SCINI, the Submersible Capable of under Ice Navigation and Imaging.
The $50,000 underwater rover— relatively inexpensive by commercial submersible standards—is about 1 meter long and 15 cm wide, can dive to depths of 300 m, and returns video with better than HD-TV resolution. Kim and her team took SCINI for its first Antarctic tests in 2007, where "it exceeded all of our expectations," functioning smoothly and allowing them to vicariously visit more of the ocean bottom than they had hoped. From the ice above, she watched on her laptop as the rover explored the flat sea floor, searching for signs of Dayton's work.
At last, one day, a shadow appeared in the distance. "You suddenly see these big, white, ghostly things coming out of the darkness toward you," Kim says.
There, on PVC plates floating on buoyed lines above the flat ocean bottom, tall, pale volcano sponges had settled as larvae decades ago and grown to a meter in diameter. As the submersible came even closer, feathery hydroids and vivid colors became apparent—the dark greens, bright yellows, and vibrant reds of smaller sponges. The effect, Kim says, was "kind of like coming up on a shipwreck." (Visit our website www.the-scientist.com for a video.)
In the end, Kim was able to relocate all Dayton's original experiment sites, and collected some preliminary data from them. SCINI's images suggest that the sponges of Antarctica's sea floor grow faster than expected during their youth—tens of centimeters each decade instead of the few millimeters per decade Dayton had observed in older animals. If her findings are confirmed, Kim says, they would be "fantastic news" for the regeneration of the scarred ocean bottom.
Kim returned to Antarctica late last year with the goal of fine-tuning the SCINI's imagery system and observing three tantalizing undersea destinations: A sponge field legendary for its gigantic volcano sponges, a gathering ground for icebergs, and the underside of a permanent ice shelf—something visited only five times in the history of Antarctic research.
She hopes that one day Dayton can join her on the ice so she can "extract every last ounce of precious knowledge out of him." If he can make it, says Dayton, now 67 and studying kelp forest ecology, "I would love to go."