Researchers Create Catalog of Antarctic Submarine Canyons

Submarine canyons are deep and large-scale incisions found on most continental margins in the world. In Antarctica, these are widespread characteristics that conduct oceanographic processes with important implications for the climate and the world’s circulation. Understanding their oceanographic, climatic, geological and ecological meaning is limited by detail, precision and extent of the canyon inventory. In a new study, scientists from the University College Cork and the University of Barcelona aimed to create the best possible catalog of canyons and antarctic submarine ravines. They identified 332 drainage networks with 3,291 flow segments, almost 5 times the number of canyons identified in previous studies.

This card shows 332 underwater canyon networks on the seabed of the Antarctic continent. Image credit: Riccardo Arosio and David Amblas, DOI: 10.1016 / J.MARGEO.2025.107608.

Submarine canyons are common geomorphic characteristics that occur on all continental margins.

These are steep valleys, generally in V with fairly narrow and winding morphologies, robust slopes, starting at the edge of the continental plateau or on the continental slope, and ending with the continental ascent or the abyssal plain.

The confined canals of less than 10 km long, generally tens of meters deep and from linear view of the plan, are called submarine ravines, and are commonly found alongside or inside canyon systems on the continental slope.

The underwater canyons transport the sediments and nutrients from the coast to deeper areas, they connect the shallow and deep waters and create habitats rich in biodiversity.

Scientists have identified some 10,000 underwater canyons in the world, but because only 27% of the sea background of the earth was mapped in high resolution, the real total is probably higher.

And despite their ecological, oceanographic and geological value, the underwater canyons remain under-explored, in particular in the polar regions.

“Like those of the Arctic, the underwater canyons of Antarctica resemble canyons in other parts of the world,” said Dr. David Ambers, researcher at the University of Barcelona.

“But they tend to be larger and deeper due to the prolonged action of polar ice and the immense volumes of sediment transported by glaciers to the continental plateau.”

For their study, the authors used version 2 of the Bathymmetrical International Table of the Southern Ocean (IBCSO V2), the most complete and detailed menu of the seabed in this region.

It uses new high-resolution Bathymetric data and a semi-automated method to identify and analyze the canyons that have been developed by the authors.

In total, it describes 15 morphometric parameters which reveal striking differences between canyons in oriental and Western Antarctica.

“Some of the underwater canyons we have analyzed reach depths of more than 4,000 m,” said Dr. Ambers.

“The most spectacular of them are in the east of Antarctica, which is characterized by complex systems of a branched canyon.”

“The systems often start with several canyon heads near the edge of the continental plateau and converge into a single main channel which descends into the deep ocean, crossing the sharp and steep gradients of the continental slope.”

“It was particularly interesting to see the differences between canyons in the two major Antarctic regions, because it had not been described before,” said Dr. Riccardo Arosio, researcher at University College Cork.

“The canyons of Eastern Antarctica are more complex and branched, often forming large canyon systems with transversal sections typical in U.”

“This suggests prolonged development under sustained glacial activity and greater influence of sedimentary processes both in erosion and deposit.”

“On the other hand, the canyons of Western Antarctica are shorter and more steep, characterized by transverse sections in V.”

“This morphological difference supports the idea that the glacial cap of the eastern Antarctic is from earlier and has experienced a more prolonged development,” said Dr Amberà.

“It had been suggested by studies of sedimentary files, but it had not yet been described in the geomorphology of the sea background on a large scale.”

“Thanks to the high resolution of the new Bathymmetric Database-500 m per pixel compared to the 1-2 km per pixel of previous cards-we could apply semi-automated techniques more reliable to identify, profiled and analyze the underwater canyons,” said Dr. Arosio.

“The strength of the study lies in its combination of various techniques which were already used in previous works but which are now integrated into a robust and systematic protocol.”

“We have also developed a GIS software script which allows us to calculate a wide range of morphometric parameters specific to the canyon in a few clicks.”

The team’s work appears in the newspaper Marine geology.

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Riccardo Arosio and David Amblas. 2025. The geomorphometry of the Antarctic submarine canyons. Marine geology 488: 107608; DOI: 10.1016 / J.MARGEO.2025.107608