Antarctica. Credit: Oleksandr Matsibura, Shutterstock
A vast network of 332 giant submarine canyons piercing several 4,000 metres over 4,000 metres is revealed under Antarctic ice waters in the region’s most detailed mapping to date.
A high-resolution submarine area survey led by David Amblàs at the University of Barcelona and Riccardo Arosio at University College Cork has identified five times the canyons of previous studies. Published survey results Science every dayhighlighting how these immeasurable valleys affect ocean circulation, ice shelf stability, and global climate patterns.
Hidden corridors in Antarctica
Submarine canyons are vast valleys carved into the seabed, often transporting sediment and nutrients from the coast to the deep sea, creating a habitat rich in biodiversity. Globally, scientists have identified around 10,000 such canyons, but only 27% of the Earth’s seabed are mapped at high resolution. This means that the actual total can be much higher.
The size and depth of the Antarctic canyon stand out. “Like people in the Antarctic submarine canyons of the Arctic, they resemble canyons in other parts of the world,” Umbras explained. “However, they tend to be bigger and deeper due to the long-term effects of polar ice and the enormous amount of sediment transported to the continental shelf by glaciers.”
In Antarctica, most are formed by turbidity flows. This is a rapidly moving current of suspended sediments eroding the seabed. The steep slopes and abundance of glacial deposits amplify these currents and contribute to the vast scale of the canyon.
East vs. West Antarctica
This study revealed a prominent contrast between the two major Antarctic regions.
“Some of the submarine canyons we analyzed are deeper than 4,000 metres,” Umbras said. “The most spectacular of these lies in the East Antarctica and features a complex, divergent canyon system.” They often start at the heads of multiple canyons near the edge of the continental shelf and converge into a single deep waterway that falls sharply into the depths of the ocean.
According to Arosio, “The gorges in the East Antarctic are more complex and divergent, often forming a broad canyon channel system with typical U-shaped cross sections,” suggesting long-term development under sustained glacial activity.
In contrast, the canyons in the West Antarctic are short, steep, and usually V-shaped, indicating different geological processes. Amblàs said this morphological disparity supports the theory that the East Antarctica ice sheet is older and longer in development. This was previously suggested by sedimentary records, but not by previous large-scale seabed mapping.
“When shelves become weak or collapse, continental ice flows rapidly into the oceans, directly contributing to rising sea levels around the world,” Umbras warned.
amblàs and arosio emphasize that current marine circulation and climate models, including those used in the Intergovernmental Panel on Climate Change (IPCC), do not yet accurately replicate the small-scale processes occurring in and around submarine canyons.
Next steps in Antarctica exploration
Researchers argue that further high-resolution mapping is essential as most of the Antarctic seabed remains unexplored. They recommend combining detailed mapping with both in-situ observation and remote sensing. This could reveal more canyons and help scientists better understand their role in the ocean and climate system.
The finding adds urgency to Antarctica research when ice shelves are already under threat from rising temperatures. It also raises doubts on the scientific and political community. If such a large-scale, climate-critical structure remains hidden, what other important features may be undiscovered?
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