Subseas canyons are among the most spectacular geological formations on the seabed. But many of these deep cuts are still undetected – especially in more remote ocean regions. Now researchers have completed the most extensive and detailed mapping of the underwater canyons off the coast of the Antarctic. Your cards show five times more sub-marine gorges around this continent than before, they belong to a total of 332 canyon networks. Many of these canyons are cut hundreds of kilometers long and kilometers into the coastal seagrow. However, there are clear differences between Western and Eastern ATARKTIs. Overall, the results suggest that the Antarctic Sea Gorges could have a greater influence on the ocean cycle, the thinning of the ice shelf and global climate change could have.
Around the mainland base of the continents, underwater gorges have buried deep into the ocean slopes. These mostly steep-walled, v-shaped canyons range from the flat shelf to the deep sea and can be several hundred kilometers long and several kilometers deep. These underwater canyons are usually formed by local currents in which a mixture of sediment and water flows down the continental slopes. Over time, these cloudy flows erode the seabed and notify it deep into it. The sub-marine gorges not only shape the topography of many continuous edges, they also play a crucial role in ocean dynamics: they transport sediments and nutrients from the coast into deeper sea areas, combine flat and deep water zones and create habitats with a high biodiversity. According to a first global inventory, there are more than 100,000 underwater canyons worldwide, which together take around 4.4 million square kilometers – at least. Because the actual number of sub -marine gorges is estimated that it is much higher.
Antarctic underwater canyons combine ice and deep sea
Underwater canyons play a particularly important role in the polar areas. “In the Arctic and Antarctic, these gorges are typically deeper into the continental slopes and width than the canyons in non -polar widths,” explain Riccardo Arosio from the University of College Cork and David Amblas from the University of Barcelona. “At the base of the slopes, they often develop into channels that extend to the deep sea over hundreds of kilometers above the seabed.” These long, deep gorges influence the transport of the sea water both from the Schelf into the depth and vice versa. In the Antarctic, these gorges flow into the deep sea through these gorges of cold, dense water that is created in areas with sea ice and malfunction and forms the antarctic deep water there. “This process is crucial for the ventilation of the deepest ocean layers and plays an important role in the global thermal jelly circulation and the long -term storage of carbon,” explain the researchers. Conversely, the canyons can penetrate warmer water from the deep layers to the Antarctic Schelf. This increases the thinning and melting of the malfunction and thus accelerates the glacier melt on the coasts of Antarctic.
Despite this enormous importance, the underwater canyons of the Antarctica have so far hardly been researched and only mapped incompletely. That is why Arosio and AMBLAS have evaluated data from the global bathymetrical database IBCSOV2. It comprises more than 25,000 billion data points that were collected as part of almost 1500 sonar maps. “Thanks to the high resolution of this new bathymetrical database – 500 meters per pixel compared to one to two kilometers per pixel on previous cards – we were able to use semi -automated techniques more reliably to identify, profile and analyze underwater canyons,” explains Ambrosio. This method allowed the depth, length and branch of the submarine gorges to be grasped along the entire Antarctic coast.
Eastern antaltic canyons are deeper, longer and more branched
The result of this evaluation is the most detailed catalog of antarctic underwater canyons so far. It comprises 3291 individual gorges that can be assigned 332 networks. This is five times more individual canyons than identified in previous maps. “Some of the underwater canyons we identify reach depths of over 4,000 meters,” says Amblàs. The length of some gorges is also considerable: with 53 of these systems, the main canyon reaches length of more than 30 kilometers. “The longest underwater canyon is located in the Wedellmeer and runs around 859 kilometers well above the continental slope and the deep-sea level,” report the researchers. The gorges around the West Antarctic Peninsula, 130 of the canyon networks are the biggest density. “These gorges are typically shorter, straight and steeper than the underwater canyons in other parts of Antarctic,” report the researchers. You attribute this high dense steep steeper to a close tectonic rejection. The differences in height on the Pacific coast of the peninsula have reinforced their movements and thus also promoted erosion.
However, the most striking is the difference between the underwater canyons of the two large antarctic regions, West Antarktis and the Eastern Attarktis. “The Eastern antaltic canyons are more complex and branched, often they form extensive canyon channel systems with typical U-shaped cross-sections,” reports Arosio. These complex systems often start in several gorges near the edge of the continental shelf and then combine into a main channel reaching into the deep sea. In contrast, the western antaltical canyons are shorter and steeper, with predominantly V-shaped cross-sections. According to the researchers, these differences are likely to go back to the fact that the Eastern antaltical ice shield was created earlier than the western antecarctic. “The longer existence of the Eastern antalstore ice shield and its glaciers led to extended periods of erosion and sediment transport,” explain Arosio and Amblas. “This could have contributed to the complexity and size of the canyon systems in the Eastern Antarctic.”
Meaning also for the melting of ice
However, the new mapping also indicates that the Antarctic underwater gorges – especially in the Eastern Antarctic – could have a greater impact on the stability of the ice shield and the glacier than previously assumed. Because if there are more and larger connections between Schelf and Tiefse, this affects the water and heat exchange. This could accelerate the ice melt more than predicting common models. “Precise climate forecasts depend on models of octech circulation, the interactions between currents and topography, especially in complex structures such as shelf channels and canyons, effectively reproduce,” explain Arosio and Amblas. “Despite their importance, however, the current ocean models are not yet able to adequately dissolve these flow topography processes.” It is all the more important to collect and evaluate other bathymetrical data from previously incomplete or only roughly mapped areas.
Source: Riccardo Arosio (University College Cork) and David Amblas (University of Barcelona, Marine Geology, DOI: 10.1016/J.Margeo.2025.107608
