Oceanographers Who Brave The Frigid Antarctic Winter

In 1914, an ambitious trans-antarctic expedition was organized by scientist/explorer Ernest Henry Shackleton. But during the middle of winter, his ship, the Endurance, was caught and crushed in the pack ice of the Weddell Sea. It wasn’t until 1988 that another ship ventured into that part of the ocean during the antarctic winter, this time with the goal of studying the delicate and complex food web of the region’s ice-edge zone, where the frozen and open ocean meet. Thoughts of Shackleton’s misfortunes may have flashed through the minds of some of the researchers on the National Science Foundation’s 210-foot research vessel Polar Duke each time they got stuck in the pack ice earlier this year. But on every occasion, they successfully freed the ship. And the hearty multidisciplinary team of oceanographers also made some unanticipated discoveries about the fragile polar ecosystem. During a 70-day research expedition conducted from June to August, the heart of the antarctic winter, the 47-member team of biological, chemical, and physical oceanographers from research institutions throughout the U.S. discovered high concentrations of tiny plants and animals that thrive throughout the winter within the pores of the sea ice. Perhaps the most significant find: the presence of krill—a tiny shrimp-like crustacean that is an important food source for whales, seals, and penguins—at concentrations denser than ever before measured. The winter expedition was the third cruise in the past five years of an NSF-funded project called AMERIEZ—for “antarctic marine ecosystem research at the ice-edge zone.” Each cruise, including others in the spring and fall, has been led by Cornelius Sullivan, director for marine biological research at the University of Southern California, Los Angeles, and David Ainley of the Point Reyes Bird Observatory, north of San Francisco. The krill discovery was important for two reasons: First, it led AMERIEZ scientists to realize that, since the small crustaceans are able to survive in such abundance, the ice must also host an abundant supply of living and growing algae and microscopic organisms for the krill to feed on. And second, the AMIERIEZ project—the first U.S. multidisciplinary project in the antarctic—allowed the scientists to look at many of those microscopic organisms, which no one had ever studied before in that frigid environment. “We didn’t anticipate that in the middle of the winter, with the darkness, the very low temperatures, and vast areas of the ocean freezing before our eyes, this would be going on,” says Sullivan. “What was really surprising to me was that the antarctic system was functioning in a business-as-normal way,” says team member Jose Tones, associate professor of oceanography at the University of South Florida, St. Petersburg. “The fish and the crustaceans seemed fine. The sea birds were all fat and happy. It wasn’t like everybody was starving to death.” The team includes scientists in each of the subdisciplines of biology, covering almost every trophic group of organisms from, as Sullivan puts it, “bacteria to whales.” This multidisciplinary group is unusual to oceanography, since most research vessels go to sea with only 10 to 25 scientists, all studying the same problem—and all researchers tending to stay aboard their ship. But the AMERIEZ group includes a mix of scientists who wanted to study organisms not only in the open ocean, but on the surface of the ice-covered waters as well. As a result, on the most recent cruise, the team had divided in half and made consecutive trips on the same ship—the Polar Duke, NSF’s research vessel with ice-breaking capability. Sullivan’s ice floe group left out of Punta Arenas, Chile, last June—a month when, in the antarctic, it is midwinter—for a 35- day voyage. Then in July, back in Chile, the group switched ship crews, and Ainley’s open-water group of scientists went back out for another 35 days. A handful of scientists, most notably those studying krill, sailed on both legs of the journey. The major challenge for each of the chief scientists during their respective 35 days at sea was to manage the diverse team projects. For Sullivan, on the pack ice, it was a challenge to keep track of each research group: At any one time a group studying seals might take a small rubber boat out to an ice floe, while another group might be collecting ice samples from the area close to the ship. Meanwhile, a third would be scuba diving below the ice, as a fourth remained on the ship to trawl for fish. “It takes a lot of tolerance on the part of all the scientists in dealing with the chief scientist, and it takes a lot of effort and tolerance for the chief scientist of the ship to be responsible for the safety of all these different experiments,” says Sullivan. Ainley agrees, saying: “The job of chief scientist is exhausting, but it’s also exhilarating. It has a lot to do with cheerleading and making sure people are awake when an opportunity comes along.” While scientists on Sullivan’s voyage studied the krill that were living in holes in the pack ice, it was on Ainley’s trip that the researchers studied the creatures in the open water. On the Ainley expedition, scientists spent more time aboard ship, which made it easier for the chief to keep track of his team but presented some scienitfic problems. On the ice floes, scientists can locate good sampling spots by looking for groups of seals and penguins, who feed on resident organisms; in the open water, deciding where to sample is more difficult. To study a variety of organisms in the water, scientists tow nets behind the ship. “It’s a real game of hide and seek,” says Ainley. “You’re sampling this little pinprick, hoping to get a representative sample of the whole ocean.” But Ainley’s own studies, which focus on sea bird ecology, proved useful and sometimes provided surprising information to AMERIEZ scientists studying zooplankton and fish. Because birds tend to gather near good food sources, they serve as indicators of the best sampling areas for scientists studying the fish that the birds eat. The benefits of Ainley’s ornithological interests for the team at large illustrates the advantage of being part of a multidisciplinary team. For example, on the spring cruise, Ainley’s work guided Torres to look at an unexpected ocean depth for one of the organisms he was trying to find. Torres, who specializes in microneckton and zoo-plankton, was trawling for one species, gigantocypris, below 500 meters—but he just wasn’t finding any. When Ainley found some of the organisms in the stomachs of his sea birds, Torres was “astounded.” Thanks to Ainley’s tip, Torres determined that unlike gigantocypris in other parts of the world, in the antarctic these organisms remain close to the surface—a finding that the two later published in the journal Science. “There’s sort of a cross-fertilization,” says Torres. “We’ve got David Ainley looking at sea bird distributions and species composition abundance, and his birds are eating our fish. We can tell how many fish there are, what their caloric value is, and how worthwhile they are as a chunk of food.” The excitement of discovery, of exploring new territory, seemed enough to keep most of the AMERIEZ researchers from thinking about their harsh working conditions—antarctic weather conditions, after all, are a far cry from the sun-baked warmth of California, Florida, and Texas climes that many of the researchers are used to. (Fortunately, the NSF had issued survival suits and insulated boots that kept team members warm enough to stay on deck or on the ice often up to eight hours at a time). Shipboard research facilities were also in stark contrast to home-institution labs. Greta Fryxell, professor of oceanography at Texas A&M, however, found that the crew on the winter cruise was sensitive to the scientists’ special needs. She spent most of her time on board the ship with a light microscope and a strobe light, studying algae—the strobe light compensates for the vibrations of the ship. “One Coast Guard engineer was extremely kind to me and would occasionally turn off the engines,” she says, “but he was taking a chance—you can’t just turn engines back on and gun the motor if you’re in trouble.”

Oceanographers Who Brave The Frigid Antarctic Winter

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