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Studying Seals' Extreme Environment Without Freezing

Weddell seals feed by diving beneath the frozen Antarctic sea ice to hunt fish in darkness and freezing-cold water at depths so great the pressure collapses their lungs.

To study creatures that inhabit such an extreme environment, scientists must cope with conditions that make daily living, let alone conducting research, a challenge.

Thanks to a new website, however, you can check out the lives of Weddell seals and the travails of the scientists studying them without venturing any farther than the nearest computer.

Created by Terrie Williams, professor of ecology and evolutionary biology at the University of California, Santa Cruz, the website chronicles her ongoing investigation of the feeding biology of Weddell seals.

Williams is a principal investigator on a research team that has been in Antarctica since the beginning of October. Her website features weekly installments with photos and field notes describing the progress of the 10-week expedition, which is sponsored by the National Science Foundation.

"I designed it for schoolchildren and teachers, because I wanted to give kids in science classes a taste of the thrill of scientific discovery--I hope to bring that moment of discovery alive," Williams said. "Through the web site, people can follow our successes and challenges while we're actually out there on the ice with the seals."

So far, the challenges have included an iceberg about the size of Rhode Island and temperatures nearly three times colder than a household freezer. The huge iceberg planted itself near the team's study site and completely altered the normal movement of the ice pack. The resulting changes in the sea ice made it hard for the researchers to predict where the seals would go.

"The research team must now rethink where we will place our camp," Williams wrote in the field notes for Week 2.

The researchers decided to try a new location where a few seals had already been spotted. With help from a team of construction workers from McMurdo Station, an American research base in Antarctica, the researchers built their field camp at a carefully selected site on the sea ice blanketing McMurdo Sound.

The centerpiece of their living quarters/field lab is a four-foot-diameter hole in the ice, drilled by a giant ice auger, for use by the seals during experiments.

Week 3 featured blowing snow and exceptionally low temperatures. "Yesterday the temperature high was minus 20 degrees Celsius (minus 4 degrees Fahrenheit) and the low was minus 27 degrees C (minus 17 degrees F)," Williams wrote. "With the blowing winds, the wind chill makes it feel like minus 57 degrees C (minus 70 degrees F) on your skin."

Shoveling the drifting snow is an ongoing task of critical importance. If too much snow builds up around the camp, its weight makes the sea ice bend and could eventually cause the camp to sink into the water. Unpredictable ice movements also make life interesting on the Antarctic sea ice.

"We are watching the floors of our camp buckle and a large pressure ridge develop behind the camp--it appears that the glacier behind us is moving," Williams said in an e-mail message earlier this week. "Seals are now popping up in our backyard because of the new cracks. It is always interesting here!"

In Week 4, the researchers observed three seal pups being born near a crack in the sea ice, with blowing snow and temperatures near minus 17 degrees C (1 degree F). They later found one pup frozen to death, but another weathered the storm and the researchers could see it growing fatter and healthier day by day.

Still to come, the researchers will be choosing seals to use in their experiments. They will mount video cameras and other monitoring equipment on top of the seals' heads to get a seal's-eye view of life beneath the ice.

Williams and her coworkers have conducted similar experiments in previous years. The resulting videotapes revealed surprising aspects of the diving and hunting behavior of Weddell seals, including a neat trick in which the seals blew bubbles into cracks in the ice to flush out fish. More surprises are sure to come from this year's expedition.

"The risk is we don't know what will happen," Williams said by e-mail. "There have been icebergs, bitter cold temperatures, lost seals, and broken equipment. The seals may swim away with all of our instruments. But all of the difficulties will be worth it if we discover or see just one thing that no one else has ever seen. With luck, those following the website will be there when it happens."

In addition to Williams, the principal investigators on the expedition are Randall Davis of Texas A&M University and Lee Fuiman of the University of Texas, Austin. The rest of the field team includes UCSC graduate student Matt Rutishauser, Jesse Purdy of Southwestern University in Georgetown, Texas, Markus Horning of Texas A&M, William Hagey of Pisces Designs (a San Diego video equipment company), and Don Calkins of the Seward Sealife Center in Alaska.

Williams holds the Ida Benson Lynn Chair in Ocean Health at UC Santa Cruz. She used funds from the endowed chair and from NSF to support the web site project. Stephen Hauskins, biology computing manager at UCSC, is providing web site support. - By Tim Stephens

[Contact: Tim Stephens]

12-Nov-2001

 

 

 

 

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