A joint US and UK mission in Antarctica has recently discovered strange structures beneath the Dotson ice shelf in West Antarctica.
The team discovered the structures using Ran, an autonomous underwater vehicle (AUV) that traveled more than 621 miles (1,000 kilometers) in a 27-day study near the ice. Ran discovered these structures in 2022, but the research findings have only recently been published Advances in Science.
“We used satellite data and ice cores to see how the ice shelves changed 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 underwater, we have been able to obtain high-resolution maps of the subsurface ice. It’s like seeing the back of the moon for the first time.”
Ran subglacial missions map the bottom of the shelf, identifying researchers with subglacial currents and the nature of the rapid melting of the ice shelf. It also revealed that beneath the shelf was a “peak and valley ice,” as the released book puts it, with plateaus and structures that look like sand dunes, albeit made of ice. The team also found indications of high melting in vertical cracks throughout the glacier.
Existing models of the glacial undercarriage cannot explain the “teardrop-shaped indentation,” as the team describes it in the paper, which they believe is due to water flow. The team emphasizes that understanding these hitherto unknown processes will be important in developing more accurate models that will better predict the melting of the Antarctic ice sheet.
“The maps produced by Ran represent a major advance in our understanding of the Antarctic ice shelves,” said Karen Alley, a glaciologist from the University of Manitoba and co-author of the study, in the same release. “We’ve had ideas about how complex the foundations of ice shelves are, but Ran got a much broader and more complete picture.”
Unfortunately, Ran has to be renamed “Run” due to its premature disappearance. In January 2024, the team returned to the Dotson shelf to repeat the surveys. But after one dive, the Ran disappeared on its next run under the shelf. The research team will need to replace the submersible if they want to continue their research—which is exactly what they are doing.
“Even though we got important data back, we didn’t get everything we expected,” said Wåhlin. “We hope that we will be able to replace Ran and continue this important work.”
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