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Dispatch 3, from the Second Data-gathering Cruise of SO GLOBEC
April 23, 2002 / Marguerite Bay: The first days of data collection on the Nathaniel B. Palmer were marked by overcast skies and low visibility. But just when it seemed endless clouds would swallow the Palmer, the sun burst through and revealed the ice-covered lands of Antarctica. Voyagers enjoyed several brilliant days that lifted their spirits. The sun shone brightly and the sea was tranquil as the Palmer made its way along the coast of Adelaide Island and, later, as it steamed deep into Marguerite Bay. Scientists observed crabeater seals in the distance as swooping birds chased the boat and an occasional white snow petrel landed on the bow for a rest. Yesterday evening, a large crowd gathered on the bridge to admire the sunset. Light pink ribbons of sky framed the snow-covered mountains of Adelaide Island, that, sculpted and imposing, resembled a giant white castle rising up out of the blue sea. "It's breathtaking," said Amy Kukulya of Woods Hole Oceanographic Institution in Woods Hole, Mass. "You look up and forget how cold you are." This morning at sunrise, the Palmer rendezvoused with its sister ship, the Laurence M. Gould, to transfer supplies. Pink streaks again painted first the sky and then the icy mountaintops as the sun peaked up slowly over the horizon. Scientific work has taken on a comfortable rhythm, as has life aboard the ship. Scientists work on alternating 12-hour shifts, most from noon to midnight or midnight to noon. E-mail comes via satellite at 9 a.m. and 6 p.m.; ship's engineer Bryan Zipperer makes nightly rounds with his bottomless bucket of Chilean chocolates; the sun rises about 8:30 a.m. and sets around 4:30 p.m. "The trip's mellow compared to last year. Everything's going pretty smoothly," said Alice Doyle, the marine projects coordinator from Raytheon Polar Services Co., NSF's logistical coordinator. Wrangling the BIOMAPERBut research in Antarctica is never completely routine; like Antarctic weather, it can be fickle and bumpy. At station 12, the zooplankton and krill research team dodged a close call with their key instrument, the Bio-Optical Multi-frequency Acoustical and Physical Environmental Recorder (BIOMAPER-II), when an electrical fire broke out in its garage--a converted blue shipping container on the back deck. Luckily, the fire burnt itself out and BIOMAPER-II was unharmed except for a layer of soot easily washed off by the ocean. BIOMAPER-II, which is towed behind the Palmer and finds krill and other zooplankton in the water, has had its share of calamities in the harsh Antarctic environment--particularly in winter ice. "We crashed it a couple of times last year," said Jennifer White, a marine technician from Raytheon. "The whole tail was completely torn away. The fiberglass nose was crunched. The VPR [Video Plankton Recorder] thing on the front was so twisted, we couldn't even bend it; we had to chop it up and weld it back together to make it work." BIOMAPER-II is a fifteen-by-three-foot white box, reminiscent of a chest freezer, adorned with an airplane tail, a black nose, and mounted black cameras that resemble coiled antennae. Wearing a round, yellow Woods Hole sticker right where an eye might be, it looks almost like a living creature. At 1700 pounds, it weighs as much as a baby whale. "It's kind of funny: they don't call it 'The BIOMAPER' they just call it 'BIOMAPER,' like it's a being, like it's this little entity," White said. Its operators refer to it affectionately as "the fish," and other scientists jokingly ask when they can watch it be fed. Seeing Through Underwater EyesThe Woods Hole team has good reason for acting like proud and protective parents. BIOMAPER is unique to Woods Hole, created in the mid-1990s by Peter Wiebe and Tim Stanton. Wiebe and Stanton took a standard piece of oceanographic equipment--one that images microscopic sea animals with high-frequency sound waves--and added capabilities no other instrument has. On this Antarctic expedition, Wiebe is using the second-generation BIOMAPER-II. BIOMAPER-II has three subsystems: the acoustics, the VPR, and the CTD (conductivity, temperature, depth). Carried together, these instruments measure the distribution of zooplankton relative to the physical structure of the ocean along each transect in the research grid. BIOMAPER-II sends sound waves up and down the water column from five "up-looking" and five "down-looking" acoustic transducers. Particles and organisms in the water scatter the sound waves and bounce them back to receivers on BIOMAPER-II. The pattern of scattering depends on the density, size, and type of particles and their distance from BIOMAPER-II. The signals are relayed to a computer through fiber-optic cables in the towline that ties BIOMAPER-II to the ship. What researchers see on their computer screens are smatterings of color that, to the untrained eye, look like an Impressionist painting of the world beneath the ocean surface. Specially trained acousticians, however, can read the code hidden in the colored pixels. For example, patches of krill might give splotches of color from red to orange, and even to black, when the patch is extremely dense. "It's a fish finder on your boat," explained Andrew Girard of Woods Hole. "But with the frequencies we're using, we're looking at microscopic stuff in the water." Girard, along with Pete Martin of Woods Hole, is one of two "personal surgeons" that accompanied BIOMAPER-II on the cruise. They jump whenever BIOMAPER-II breaks, Girard said. Interpreting the acoustical signals is tricky business. Researchers can't always be sure of what the acoustic transducers are seeing. "The acoustics can tell you that there's a patch of something there, but it's a patch of something," Girard said. That's where BIOMAPER-II beats standard oceanographic tools that depend solely on acoustics. BIOMAPER-II carries two high-resolution cameras--jointly called the VPR, or "video plankton recorder"--that provide visual confirmation of the acoustical data. As BIOMAPER-II moves through the water, the VPR records all the microscopic animals passing through a small volume on the front of BIOMAPER-II, giving scientists a visual sample of what's down there. "If Peter [Wiebe] sees a big red splotch on his acoustics, and says that's a patch of krill, we fly BIOMAPER down through," Girard said. "If krill start popping up on the VPR, we know that the patch was identified correctly." Like the acoustics data, the visual data is fed to the BIOMAPER-II control van (another converted shipping container) via fiber-optic cables. Equipped with several video monitors, the white van resembles a building security office. But instead of monitoring people, these scientists are keeping tabs on microscopic creatures in the ocean: copepods, diatoms, and radiolarians, to name a few. The VPR, like security cameras at a bank, is constantly recording video, making reams of tapes. "You go from getting oodles of plankton samples to oodles of tapes," said Phil Alatalo of Woods Hole pointing to a giant box of tapes. Fortunately, much of the identification and counting of plankton can be done by computer, saving researchers from having to watch hours and hours and hours of plankton flying by on the screen. "It's not perfect," said Alatalo, adding that the team often still counts manually or semi-automatically. "The human eye is always better," he said. Challenges that keep them coming backBesides VPR, another way to ground-truth BIOMAPER-II's acoustical data is to directly sample the water with nets--which scientists such as Carin Ashjian of Woods Hole are doing periodically from the Palmer. Additionally, scientists are developing mathematical models to help them better interpret the acoustical data. The zooplankton and krill group have been surprised by the results they are seeing so far. "It's been very different," said Ashjian. "We haven't seen the krill like we saw last year." The fall cruise last year saw a lot of young krill in a specific layer of colder water called winter water, and they also saw lots of krill on the continental shelf, Ashjian said. The unpredictability of the science and of the day-to-day living may be exactly what draws scientists, technicians, and crew alike to the Antarctic. "I keep coming down just because it's something different every time," said marine technician Jennifer White. "You wake up every day and look out your porthole, and who knows where you're going to be and what you're going to do." The unpredictability offers challenge, excitement, and even a little fear factor, said marine technician Steve Tarrent, adding that he was always fascinated and awed by Shackleton's adventures. "You leave port, and you've got a certain amount of material things, a certain amount of talent, and a certain amount of ingenuity and energy," Tarrent said. "Any problems that develop, you're going to have to deal with them with what you've got right here," he said. "There's a sort of grace to that." Indeed, the story of how BIOMAPER-II held together last winter with its make-do plywood tail and its taped-up VPR, is a graceful tale of ingenuity and humility. Of course, this didn't stop the zooplankton team from bringing two VPR's for BIOMAPER-II this time, just in case.
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