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Philip Hauge Abelson Seminar Explores "New Horizons in Polar Science"
The narwhal (Monodon monoceros), a cetacean of 15 feet or more in length, has a surprisingly sensitive tusk ranging from six to 10 feet long
Photo © Glenn Williams
Strange whales with long, sword-like tusks, dwindling Adélie penguin populations, microorganisms entombed in ice, and the cosmic origins of the universe were among the mysteries explored by speakers at the annual Philip Hauge Abelson Advancing Science Seminar at AAAS.
As global climate change affects Earth's poles—and especially the highest latitudes—the hardest, native people and their cultures are increasingly vulnerable, leading researchers warned during the seminar, moderated by AAAS President-elect James J. McCarthy, the Alexander Agassiz Professor of Biological Oceanography at Harvard University.
"It has been said that polar regions are like the canary in the coal mine, and when the canary drops, it's time to leave the mine," said McCarthy, who co-chaired the Intergovernmental Panel on Global Climate Change (IPCC), Working Group II (2001). "But we have no exit path."
The 30 October event, "New Horizons in Polar Science," was planned in recognition of the International Polar Year and in honor of Philip Abelson, who served as editor of the journal Science for 22 years, and then as senior adviser to AAAS until shortly before his death at the age of 91. Abelson "had almost no interest in the past," said AAAS Chief Executive Officer Alan I. Leshner, executive publisher of Science. "He was a man who was only interested in where science was going."
Martin T. Nweeia
In that spirit, Martin T. Nweeia described his efforts to integrate scientific observations with indigenous knowledge in the Arctic, to better understand the narwhal (Monodon monoceros), a cetacean of 15 feet or more in length, with a tusk ranging from six to 10 feet long. Nweeia, an instructor at the Harvard School of Dental Medicine and a research associate in the Smithsonian Institution's Marine Mammal Program, said narwhals had been observed in Western Greenland migrating two weeks later than usual, in late October and early November. So, his research team set out to learn whether the whale might provide new insights to climate change in the Arctic.
Researchers also wanted to learn more about the creature's unusual traits, especially the giant, horizontally impacted tooth piercing its upper lip, Nweeia said. Roughly 1.5 percent of Narwhals have two tusks, he noted. Further study of fresh samples revealed tube-like structures extending from the core to the exterior. The tubules seem to allow narwhals to detect pressure, temperature, osmotic gradients, and tactile sensations with their tusks, Nweeia said. Thus, narwhals may use their tusks to find food or ideal mating waters, and navigate a deep salty layer of sea water to avoid entrapment by ice.
Research colleague Naomi Eidelman discovered yet another peculiar feature of the narwhal's tusk: Material near the inner tube of the tusk was hard, whereas the exterior was softer, "as if the tooth were inside-out," Nweeia said. Not only that, but the tusk can flex a foot in all directions, confirming Inuit knowledge about the tusk's flexibility.
To take advantage of traditional knowledge of narwhals, Nweeia's group also captured video and audiotape of interviews with elders and hunters in six Arctic communities. Through that effort, for instance, the researchers learned from Rasmus Avike of Qaanaaq, Greenland, that he believes Narwhals molt in brackish water inlets—a detail that still must be confirmed by others. Hunter David Angnatsiak of Pond Inlet, Baffin Island, in Nunavut, Canada, has reported spotting narwhals in feeding grounds where he has never seen them before. "I realized, three years into the experience, that it took someone to listen," Nweeia said of his work with Arctic peoples.
F. Stuart "Terry" Chapin III
F. Stuart "Terry" Chapin III, professor of ecology at the University of Alaska-Fairbanks, also noted the increasing impact of global climate change on residents of the Arctic. As climate change results in warming summers, fixed infrastructure has made it more difficult for communities to relocate, he noted. Thus, wildfires related to global climate change can claim a way of life for a generation of indigenous people who rely upon hunting animals such as caribou. It can take up to 80 years for caribou populations to return to regions devastated by fire, he added.
At the other end of Earth, on the western Antarctic peninsula, a population once pegged at 16,000 breeding pairs of Adélie penguins near Anvers Island and Palmer Station has been shrinking so that only 3,000 pairs of Adélie penguins now remain, said ecologist William Fraser of the Polar Oceans Research Group, whose work is funded by the U.S. National Science Foundation. Global climate change is a primary reason for the decline of Adélie penguins, according to Fraser. Winter temperatures at three U.S. research stations on the western Antarctic peninsula, below the tip of South America, have increased 5.4 times more than the global average since 1950, he noted. The duration of the annual sea-ice season has decreased by 85 days over the past 25 years.
Flightless Adélie penguins depend upon sea ice to reach feeding areas where they can find krill, he explained. Both sea ice and krill populations have been shrinking around Anvers Island, and to make matters worse, warmer temperatures have increased evaporation from the ocean, thus increasing winter snowfall. Too much snow makes it difficult for the penguins to build their pebble nests, lay eggs, and raise their young before krill season ends, Fraser has reported. His latest research has focused on better understanding the Adélie penguins' feeding habits, particularly near deep-sea canyons called polynyas, and the north-to-south migration of species. Adélie penguins need sunlight for foraging, he noted, so they can't venture too far south into the Antarctic darkness. Yet, populations of other species of penguins have been increasing south of Anvers Island, he added.
Much of Antarctica remains an unexplored scientific frontier, noted John C. Priscu, professor of ecology at Montana State University. New investigations of the Amazon-sized river basins and huge subglacial lakes beneath Antarctica's icy surface are revealing "an oasis of life in a polar desert," he reported. Specifically, a limited initial number of samples extracted from subglacial environments revealed the presence of cold-loving microorganisms, and DNA sequencing suggested that many of these organisms are closely related to microbes that "eat rocks and use carbon dioxide to make a living," he said.
The subglacial microorganisms must withstand profoundly inhospitable conditions, including continuous subzero temperatures, high pressure and continuous darkness. On 28 July 1983, for example, the temperature reached -128.6 degrees Fahrenheit at Vostok Station, where Russian researchers are now within 100 meters of drilling into Lake Vostok, Priscu said. Based on data in hand, he said: "We can no longer consider the Antarctic ice sheet a big lump of ice covering frozen ground." Emerging information suggests a "living ice sheet," containing large stores of organic carbon and thriving microbial populations, he added.
John E. Carlstrom, professor of astronomy and astrophysics at the University of Chicago, explained how he uses the "wonderfully cold, clear, transparent atmosphere" of the South Pole and a 10-meter telescope to better understand how the universe formed in a Big Bang some 13.7 billion years ago. By studying cosmic microwave background radiation, for instance, researchers can develop a snapshot of the infant universe. Physicists also are continuing to unravel the mysteries of dark matter, which makes up some two-thirds of all matter in the universe, and galaxy clusters. The largest objects in the universe, galaxy clusters "formed through a tug of war between dark energy and dark matter through cosmic time," Carlstrom explained.
Francis Halzen, a professor of physics at the University of Wisconsin-Madison, is working with a team that hopes to install "a billion-ton crystal ball" called the IceCube Neutrino Detector at the South Pole by 2011. Once completed, the detector will harness Antarctic ice using photomultipliers hanging from many strings drilled into the surface of the continent to detect high-energy particles called neutrinos, which can carry information from the edge of the universe. Like an earlier-generation detector, IceCube will spot neutrinos as they rocket through the Earth, sometimes crashing into atoms in the ice to create particles called muons and leaving blue light in their wake.
Polar ice provides a "magnificent library of the history of the planet," said keynote speaker Robert W. Corell, director of the Global Change Program for The H. John Heinz III Center for Science, Economics and the Environment. The past 100,000 years have been a "sweet spot" for human beings, characterized by a climate that allowed our species to flourish, he said. But temperatures have been rapidly rising in correlation with increases in atmospheric greenhouse gases such as carbon dioxide, methane, and nitrous oxide. The respected Intergovernmental Panel on Climate Change (IPCC) has concluded that this warming is "very likely" due to human activities including fossil-fuel burning and deforestation, and models of natural causes can't fully explain the predicted increases in temperature.
"It is now clear that we are seeing a warming signal, and we are principally responsible for the warming we are seeing," said Richard Alley, the Evan Pugh Professor of Geosciences at Pennsylvania State University. As the tips of ice sheets are calving into the oceans, he noted, they are losing the natural "buttresses" that hold back walls of ice behind them, causing an eight-fold increase in the speed of loss.
In Antarctica, for example, the Larsen B ice shelf collapsed, leaving the remaining region vulnerable to disintegration. In Greenland, meanwhile, gaping rivers are pushing water beneath the ice sheet, lubricating and accelerating ice loss. If Greenland were to disintegrate entirely, Alley said, sea level would rise by six meters, though over many centuries, submerging the lower third of Florida, much of Louisiana, and many other regions of the world.
A less catastrophic melting of Greenland, causing a one-meter sea level rise, would claim much of the Harvard University campus, according to James G. Anderson, the school's Phillip S. Weld Professor of Atmospheric Chemistry whose father Paul Anderson taught Phil Abelson. A three-meter rise in sea level would cause much of Boston to disappear.
Meanwhile, 600 gigatons of carbon are locked in the melting polar caps—and if it is released into the atmosphere, it could drive an acceleration in the cycle of warming. The current U.S. federal research program is insufficient to address climate-change and energy challenges, according to Anderson. "This country is sleep-walking in terms of grappling with the scale of the problem," he said.
5 November 2007