Grander Canyons
There are subsea canyons far bigger than the Grand Canyon.
The Grand Canyon is 6,093 feet (1,857 meters) deep, but the Zhemchug Canyon, located in the middle of the Bering Sea, is 8,530 feet (2,600 meters) deep.
The Grand Canyon is 277 miles (446 kilometers) long, but the Kroenke Canyon in the western Pacific Ocean is 480 miles (700 kilometers) long. It is the longest and the most voluminous submarine canyon yet discovered.
There are around 10,000 submarine canyons on Earth, covering around 11% of the continental slope, and they are an important source of ocean biodiversity, they transport sediment and pollution and they can create hydrocarbon reservoirs.
Despite their size and importance, they are still a frontier for scientific research - a new 6,890-foot (2,100 meter) canyon was discovered last year off Antarctica by acousticians on board the icebreaker RSV Nuyina.
Earlier this year, scientists at MBARI developed a new investigative technology, Geo-Sense, a new portable instrument that uses distributed acoustic sensing (DAS) technology for long-term, high-resolution monitoring of geological processes in canyons. DAS involves sending ultrashort pulses of laser light down a fiber-optic cable and analyzing millions of tiny reflections (backscatter) to essentially convert the cable into a motion sensor. The technology can track seafloor processes over long distances and in high resolution.
In the latest issue of Marine Technology Reporter magazine, Celia Konowe talks to Dr Meg Baker of Durham University about another technology development for understanding the turbidity currents in canyons. These seismographs detect and record ground motion, and they have been used to record the longest runout sediment flows ever measured in action, travelling more than a thousand kilometers along the Congo Canyon.
Still, more established technology is also playing a role in understanding the geology of canyons. In 2023, new ocean depths and seascapes along the East Antarctic continental shelf were revealed thanks to deep-diving seals. Fitted with small satellite-linked devices that measured temperature, salinity and depth, some were diving 1,000 meters deeper than the expected water depth. The new data gathered by the seals revealed previously unknown underwater features including the Mirounga-Nuyina Canyon. It too is deeper than the Grand Canyon.