Led by researchers at the University of Houston and the Alfred Wegener Institute for Polar and Marine Research, International Ocean Discovery Program Expedition 379 left Punta Arenas, Chile, in January for a two-month trip to Antarctica on the scientific drillship JOIDES Resolution.

"The West Antarctic Ice Sheet is extremely sensitive to changes in climate," said James Allan, a program officer in NSF's Division of Ocean Sciences. "It has the potential to disintegrate, raising global sea level by 11 to 14ft or more. This expedition is studying the history of the ice sheet over millions of years to document the past interplay between seawater and air temperature and how that led to ice gain or loss."

Julia Wellner, a sedimentologist at the University of Houston and co-chief scientist on the voyage, said that marine-based ice in West Antarctica is critical to understanding how a warming planet will affect sea level rise because this ice is less stable than ice on land. As seawater warms, ocean ice melts from below. To date, the West Antarctic Ice Sheet has sustained the most ice loss in Antarctica.

Wellner and other geologists will collect and study sediment cores that allow scientists to determine how ice sheets behaved in the past. Expedition researchers will then reconstruct the history of the ice sheet over tens of millions of years.

The scientists will drill deep into the seafloor, retrieving cores that are hundreds of feet long and contain a record of environmental change. Geologists will study these cores to determine how the various sediment layers were deposited, and when the layers formed.