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Science notebook--News from Antarctica and beyond
"These very cold days provide the best conditions for astronomical observations--clear skies and low wind," commented South Pole meteorologist Matt Wolf, one of 28 people spending the winter at the research station. "On the downside," Wolf added, "power usage is at a maximum and vehicle operation is almost impossible." Amundsen-Scott South Pole Station, run year round by the National Science Foundation, supports ongoing studies in astronomy, astrophysics, atmospheric sciences, and other disciplines.
Temperatures in August followed suit. Although the monthly average did not break a record, two record daily lows were reached. On 30 August, the temperature dipped to -76.1°C (-105.0°F), breaking the previous record for the date of -72.0°C (-97.6°F) set in 1995, and on 31 August, the low of -76.4°C (-105.5°F) broke the old record for the date of -73.9°C (-101.0°F) also set in 1995.(LExEn), involving more than 20 research projects and 40 scientists.
One contingent of the LExEn awards will focus on microbial life in Antarctica. Four studies will examine the relationship between microbes and the harsh south polar environment.
Scientists once considered the antarctic ice sheet to be one of the most stable features on the Earth's surface. During the last decade, however, some scientists have begun to question that stability, pointing to new research that suggests that the ice sheet diminished greatly sometime in the last several million years. Understanding just how stable the ice sheet has been over history will help scientists predict how global warming might affect sea levels in the future. Should the ice in Antarctica melt completely--an unlikely scenario--the world's oceans would rise 60 meters, the height of a 12-story building.
Gary Wilson, a postdoctoral fellow at the Byrd Polar Research Center at Ohio State University, believes that the New Zealand find points to a volatile, rather than a stable, history for the east antarctic ice sheet. "The most striking thing about this record is the variability it shows," Wilson said. "There are more than 30 rises and falls of global sea level--changes of as much as 65 feet--between 2 and 6 million years ago." Wilson believes that these changes can be attributed to growing and shrinking of the antarctic ice cover. Large-scale changes, during which the mass of the current ice sheet diminishes or increases by half, occur about every 3 million years, according to Wilson's theory, and small-scale changes, reductions and increases of about a quarter of the current mass of the ice sheet, could be occurring, he believes, as often as every 300,000 years.Ohio State University, who first determined that the fossil was the end of a crayfish's fixed finger, the stationary part of the claw. "The presence of crayfish in deposits this old," Babcock explained, "tells us that there probably were very complex freshwater ecosystems thriving by the end of the Paleozoic."
Babcock estimates that the crayfish from which the claw came was 15 to 30 centimeters long. Then as now, crayfish served both as a vehicle for cycling nutrients through freshwater ecosystems and as a primary food source for other animals. The fossil claw, Babcock speculates, was probably what was left from a predator's meal.
Another find, this one by Vanderbilt University geologist Molly Miller and Ohio State University professor emeritus of geological sciences Jim Collinson, not only supports the early development of crayfish indicated by Isbell's find, but also indicates that when the species first appeared, Antarctica was far warmer than it is now. Miller and Collinson found intricate networks of ancient crayfish burrows in deposits of rock along Kitching Ridge, about 37 kilometers from Isbell's find on Mount Butters. Some of the burrows are over 100 centimeters long and up to 15 centimeters in diameter, and they strongly resemble the burrows of modern crayfish digging in warm stream banks. "Crayfish have a very narrow temperature range within which they have to live," Babcock pointed out. "They usually must have free running water that is between 10°C and 20°C (50°F and 68°F) for at least three months out of the year. So if they were there, the climate had to be at least that warm." If Antarctica were that warm, Babcock extrapolated, "I don't know what that means for total world temperature, but my impression is that it would be pretty warm."meteorite found in the Allan Hills region of Antarctica might hold fossilized evidence of microbial life on Mars, both the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA) called for further research. Working together, the two agencies have launched an interdisciplinary program and funded studies (19 by NASA, 7 by NSF) to investigate possible traces of ancient Martian life in the meteorite, designated ALH84001 by the researchers who found it in 1984.
Some research will analyze ALH84001 itself; other studies will focus on terrestrial regions that have features similar to those of ancient Mars, such as hot springs and other extreme habitats of Earth microbes, to provide a better context for understanding the structure of ALH84001. The new research will include
"During different phases of testing," said Dave Lavery, telerobotics program manager at the National Aeronautics and Space Administration, which funded the development of the robot by Carnegie-Mellon University in Pittsburgh, "we configured the robot to simulate wide-area exploration of the Moon, the search for past life on Mars, and for the gathering of meteorite samples in the Antarctic. Nomad met or exceeded all of our objectives for this project."
Nomad's successor will join its human counterparts to search for meteorites in Antarctica during 1998 and 1999, but so far it has not been scheduled for any upcoming space missions.