Discovering the Depths: Exploring the World’s Subsea Canyons

Subsea canyons are some of the most fascinating and mysterious features of the ocean floor. These underwater chasms rival some of the most famous canyons on land, such as the Grand Canyon, in terms of size and depth.

One such canyon, the Zhemchug Canyon, located in the Bering Sea, dwarfs the Grand Canyon in depth, plunging to an astonishing 8,530 feet (2,600 meters) deep. In comparison, the Grand Canyon is a mere 6,093 feet (1,857 meters) deep.

But it’s not just the depth that sets these subsea canyons apart. The Kroenke Canyon in the western Pacific Ocean stretches an impressive 480 miles (700 kilometers) in length, making it the longest and most voluminous submarine canyon discovered to date. In contrast, the Grand Canyon measures 277 miles (446 kilometers) in length.

Despite their immense size and importance, subsea canyons remain largely unexplored and are still a frontier for scientific research. Just last year, a new 6,890-foot (2,100 meter) canyon was discovered off Antarctica by acousticians aboard the icebreaker RSV Nuyina.

Exploring Subsea Canyons with Cutting-Edge Technology

Scientists are constantly developing new technologies to study and understand these enigmatic underwater features. One such innovation is Geo-Sense, a portable instrument developed by researchers at MBARI that uses distributed acoustic sensing (DAS) technology for high-resolution monitoring of geological processes in canyons. By analyzing backscatter from ultrashort pulses of laser light sent down a fiber-optic cable, Geo-Sense can track seafloor processes over long distances with unparalleled precision.

In addition to Geo-Sense, seismographs have been instrumental in studying turbidity currents in canyons. These devices detect and record ground motion, providing valuable insights into sediment flows. In the Congo Canyon, seismographs have recorded sediment flows traveling over a thousand kilometers, setting new records for the longest runout sediment flows ever measured.

Unveiling the Secrets of Subsea Canyons

Even established technologies are shedding new light on the geology of subsea canyons. In 2023, deep-diving seals equipped with satellite-linked devices uncovered previously unknown underwater features along the East Antarctic continental shelf. These intrepid marine mammals dove deeper than expected, revealing new ocean depths and seascapes, including the Mirounga-Nuyina Canyon, which rivals the Grand Canyon in depth.

With ongoing advancements in technology and exploration, our understanding of subsea canyons continues to evolve. These underwater wonders not only showcase the vastness and complexity of the ocean but also hold valuable insights into the Earth’s geological processes and biodiversity.