Friday, April 24, 2009

University of Georgia paleontologist helps unravel strange lack of fossils in Antarctica; results could lead to reappraisal of continent’s past

The sun never set. Sally Walker, a paleontologist from the University of Georgia, could walk outside the scientific research station any time, day or night, into a dazzling world of dry valleys and vistas of ice. But the sun, circling the sky, was always visible on the surface of the cold Earth.

Welcome to Antarctica, bottom of the world and home to an intriguing mystery that has baffled researchers for years. In frigid waters off the continental coast, there are large numbers of species that flourish, from bizarre serpent starfish to a group of microscopic creatures called foraminifera or forams. And yet, weirdly, there is little evidence of any fossil creatures in seafloor sediments.

Why? That’s the question, but finding the answers is intriguing a team, of which Walker is a principal investigator. The research group, sponsored by the National Science Foundation, isn’t simply wondering about ancient remains of tiny, ice-loving creatures. Answers may help explain everything from the evolution of Antarctic ecosystems to reasons for global warming.

“One of the main questions is how ice affects the presence of fossil invertebrates on the Antarctic seafloor,” said Walker. “But the processes involved are very complex, and unraveling them will take more than a single approach.”

Indeed, Walker is working with two veterans of Antarctic research, Molly Miller of Vanderbilt University and Sam Bowser from the New York State Department of Health’s Wadsworth Center. The team was in Antarctica from October to December of last year, during the continent’s “summer,” though that’s a relative term, because wind chills at the team’s research outpost often reached 20 degrees below zero.

Walker, in UGA’s department of geology, part of the Franklin College of Arts and Sciences, was making her first trip to the frigid continent, but the new research fit right into work on which she’s spent a lifetime: taphonomy, the study of the process of fossilization.

The trip to the bottom of the world is long and arduous. Walker first flew to Christchurch, New Zealand, and then took a flight to Ross Island in Antarctica, the location for more than half a century of McMurdo Station, a thriving scientific research community, especially in the so-called Austral summer, which lasts from October to January.

“MacTown, as McMurdo is called by the inhabitants, is run by the National Science Foundation to investigate a wide range of science in extreme conditions, from physics to biology,” said Walker. “About 1,300 people are there in the Austral summer, with the majority of residents comprising carpenters, food service professionals, technical engineers, helicopter aviation experts and other highly trained support individuals who are essential to achieve high-quality science. Without them, there would be no science.”

From McMurdo, Walker and her team members flew on to a much smaller research site called New Harbor, which is at the mouth of a dry valley, a moraine-filled area of pebbles and soil that fronts on a much-studied frozen bay. Here, they camped in small permanent structures for the duration of their stay.

Just 20 years ago, this was, literally and figuratively, the end of the Earth—barely, if at all, in touch with the rest of the world. Now, the site not only has satellite communications links, it has Wi-Fi so that researchers can use and surf the Internet, even in the field.

The team is thus able under much better circumstances to delve into the abiding mystery of why there are few signs of fauna in the fossil records from cores taken beneath the ice in the bay. The team’s future findings could have widespread significance, said Tom Wagner, program manager of Antarctic Earth Sciences in the NSF’s Office of Polar Programs, which is funding the research.

“It’s important information because it would tell us about past ecosystems while providing another perspective on climate change,” Wagner told The Antarctic Sun, NSF’s online news source for information on science in that icy continent. “It could be that [fossils] aren’t preserved, but it could also mean that we just don’t know how to interpret the records that we have. And that’s what makes this project so exciting—it could lead to a total reappraisal of Antarctica’s past.”

There are many physical and chemical processes that may be involved with the mystery of the missing fossils, said Walker, ranging from the geochemistry of the icy waters to the action of so-called pressure ridges—places where frozen seawater collides with the shores, causing a number of changes in the ecosystems.

While a reappraisal of Antarctica’s past might be seen as enough to learn, much more is at stake, because the answers, when uncovered, could have implications for understanding global warming.

Whatever the team discovers—and it will return in the Austral summer of 2010 to follow up on its work—the science is taking place at one of the most forbidding and gorgeously beautiful places on Earth. Antarctica is the driest, windiest and coldest continent on Earth, but it is also drawing increasing interest from researchers, as each year scientists from as many as 27 different nations conduct experiments not reproducible in any other place in the world.

One thing Walker brought back to Athens has less to do with science than with the amazing individuals who do such important work under in such a remote but staggeringly beautiful place.

“Everyone works like a tightly interwoven civilization despite the extreme weather conditions, cramped dormitories, and lack of privacy,” she said. “It is awe-inspiring to watch and to participate in such an endeavor.”

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