UA Researcher Helps to Understand Possible Antarctic Glacier Collapse

From the May 2018 Desktop News | A joint research project between scientists from the United States and United Kingdom will be one of the most detailed and extensive examinations of a massive Antarctic glacier ever undertaken.

Dr. Rebecca Minzoni
Dr. Rebecca Minzoni

Dr. Rebecca Totten Minzoni, an assistant professor of geological sciences at The University of Alabama, has a role to play as a marine geologist and paleontologist in the roughly $25 million research collaboration.

The collapse of the Thwaites Glacier in West Antarctica could significantly affect global sea levels. It already drains an area roughly the size of Britain or Florida, accounting for around 4 percent of global sea-level rise — an amount that has doubled since the mid-1990s.

The U.K. Natural Environment Research Council and the U.S. National Science Foundation will deploy scientists to gather the data needed to understand whether the glacier’s collapse could begin in the next few decades or centuries.

The project involves around 100 scientists from world-leading research institutes in both countries alongside researchers from South Korea, Germany, Sweden, New Zealand and Finland, who will contribute to the various projects. These projects aim to deliver answers to some of the big questions for scientists trying to predict global sea-level rise.

“For more than a decade, satellites have identified this area as a region of massive ice loss and rapid change,” said the lead U.S. scientific coordinator, Dr. Ted Scambos, of the National Snow and Ice Data Center. “But there are still many aspects of the ice and ocean that cannot be determined from space. We need to go there, with a robust scientific plan of activity, and learn more about how this area is changing in detail, so we can reduce the uncertainty of what might happen in the future.”

Totten Minzoni will use her expertise in finding clues to the past behavior of Thwaites Glacier through what is left behind in the offshore sediment to inform models for how the glacier could behave in the future.

Antarctica’s glaciers contribute to sea-level rise when more ice is lost to the ocean than is replaced by snow. To fully understand the causes of changes in ice flow requires research on the ice itself, the nearby ocean and the Antarctic climate in the region.

Satellites show the Thwaites region is changing rapidly with warmer currents swirling around it, reaching under the ice shelf and working as a sort of lubricant that melts it from below. Not enough, however, is known about this process and how extensively it reaches under the ice shelf.

The project will deploy the most up-to-date instruments and techniques available, from drills that can make access holes 1,500 meters into the ice with jets of hot water to autonomous submarines.

Totten Minzoni will be aboard a research vessel where her part of the international team will extract cores of sediment from the sea floor to reveal the conditions around the ice sheet for the past 12,000 years.

“It’s just like stepping back in time because each layer tells you about a different time period and the glacial and oceanographic conditions,” she said.

Specifically, Totten Minzoni and her students will look for the silica walls of microscopic, single-celled organisms, called diatoms, which can be preserved in sediment for millions of years. The abundance of the diatom microfossil remains, and the species present at different intervals provide clues about the water that supported them, whether it was warm or cold, and whether there was sea ice or large ice shelves at the time.

Combined with dating of the sediment cores, Totten Minzoni’s findings will help researchers understand the rates of past glacier retreat, especially in the presence warm water, which can be used to understand how Thwaites Glacier could behave in similar waters today and in the future.

“The whole focus of this large project is have a more accurate model for what the contribution of Antarctica to sea level rise is going to be,” she said.

Totten Minzoni’s team of marine geologists, Thwaites Offshore Research (THOR), is one of the eight projects funded by the joint NSF and NERC grant, and is led by the University of Houston and the British Antarctic Survey, with collaborators from Rice, Columbia and Exeter universities.