A collaborative mission operated by the U.S. and U.K. in Antarctica recently discovered strange structures on the underside of the Dotson ice shelf in West Antarctica.
The team found the structures using Ran, an autonomous underwater vehicle (AUV) that ventured over 621 miles (1,000 kilometers) over a 27-day survey along the glacier. Ran discovered the structures in 2022, but the research findings have only recently been published in Science Advances.
“We have previously used satellite data and ice cores to observe how ice shelves change over time,” said Anna Wåhlin, an oceanographer at the University of Gothenburg and lead author of the paper, in a British Antarctic Survey release. “By navigating the submersible into the cavity, we were able to get high resolution maps of the ice underside. It’s a bit like seeing the back of the moon for the first time.”
Ran’s under-ice missions mapped the shelf’s underside, cluing the researchers into the subglacial currents and the nature of the ice shelf’s rapid melt. It also revealed that the underside of the shelf had a “peak and valley ice-scape,” as the release put it, featuring plateaus and formations resembling sand dunes, albeit made of ice. The team also found indications of high melt in vertical fractures throughout the glacier.
Existing models of glacial undercarriages cannot explain the “enigmatic teardrop-shaped indentations,” as the team described them in the paper, which they believe are due to water flow. The team emphasizes that understanding these hitherto-unknown processes will be crucial for developing more precise models that will better predict the melt of Antarctic ice.
“The maps that Ran produced represent a huge progress in our understanding of Antarctica’s ice shelves,” said Karen Alley, a glaciological from the University of Manitoba and the study’s co-author, in the same release. “We’ve had hints of how complex ice-shelf bases are, but Ran uncovered a more extensive and complete picture than ever before.”
Unfortunately, Ran should probably be renamed “Run” given its untimely disappearance. In January 2024, the team went back to the Dotson shelf to repeat the surveys. But after just one dive, Ran disappeared on its next routine run beneath the shelf. The research team will need to replace the submersible if they want to continue their research—which they of course do.
“Although we got valuable data back, we did not get all we had hoped for,” Wåhlin said. “We hope to be able to replace Ran and continue this important work.”
