Antarctica research may shed light on polar ice breakdown

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Julia Wellner is looking forward to her two-month-long, taxpayer-funded cruise, but there won’t be any poolside lounging, spa visits or blackjack tables.

Instead, the University of Houston marine geologist will be charging through frigid waters aboard a 300-foot ice-breaking ship, collecting Antarctic sediment samples that could shed new light on melting polar ice caps and rising sea levels across the globe.

The National Science Foundation in September awarded Wellner, visiting professor and researcher of geosciences at UH, a $269,000 grant to support a research cruise to Antarctica, where she will study the area that was the Larsen B ice shelf.

When this massive block of ice – about the size of Rhode Island and up to 200 meters thick – broke off from the continent in 2002 and floated away, it was an international news event and took scientists by surprise. Experts believe it was caused by rising temperatures and could portend further breakdown of the ice cap as the planet continues to warm.

By studying the sediment of the ocean floor beneath the Larsen ice shelf, Wellner hopes to identify the telltale signs of an ice shelf break. Her findings could help scientists predict future ice shelf collapses and their impact on sea levels.

The melting of ice shelves – which are huge sheets of ice floating over water – was previously thought to have little impact on sea levels. However satellite data has shown that melting ice shelves contribute to rising seas through their impact on glacier flows, Wellner said.

Because Antarctica and Greenland remain two of the biggest unknowns in global climate modeling, understanding ice shelf breakdown can help scientists better predict ocean levels as the polar ice melts, Wellner said.

By taking sediment samples from as deep as 80 feet below the sea floor, Wellner can assess the condition of the Larsen ice shelf going back 20,000 years. By verifying that the area has not seen open water in all that time, scientists can confirm that the ice break was caused by rising temperatures and was not a cyclical event.

Her upcoming research cruise will not be Wellner’s first encounter with the break up of the Larsen B ice shelf. While on a research vessel in the Weddell Sea in 2002, Wellner and other scientists aboard the ship noticed many more large icebergs in the water than was usual. Only later did scientists realize the ice shelf had broken and the icebergs were the remains of the Larsen B.

Wellner’s two-month cruise to the Antarctic Peninsula will begin in January 2009, with three follow-up trips scheduled for the next four years. She will set sail from Chile aboard the Nathaniel B. Palmer, a research vessel operated by the NSF. It carries about two dozen scientists conducting a variety of Antarctic-related research.

“It’s amazing to be on this boat,” Wellner said. “I can’t think of a luckier way to do research.”

After traversing the rough waters of the Drake Passage to reach Antarctica, the ship begins the arduous task of cutting its way through the ice. Rather than ramming the ice with sheer horsepower, the ship rides up on top of the ice and uses its weight to break the ice.

The scientists and crew live on the ship. Wellner will have a room with a heater and a private bathroom. Although January is summer in Antarctica, the temperature is still comparable to Wisconsin in winter, she said.

Rolando Garcia
Natural Sciences and Mathematics Communications

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