Wild weather reveals hidden valley in Antarctica, January 16, 2024
A huge underwater canyon in Antarctica has been discovered by acoustic experts aboard the icebreaker RSV Nuyina.
The valley was discovered when wild weather forced resupply work at the Casey Research Station to be temporarily suspended.
Instead of sitting and waiting for the weather to pass, the expedition leadership decided to use the time to map the sea floor at nearby Adams Glacier, about 70 kilometers away.
What they found was remarkable – 2,100 meters deep, 9,000 meters wide, and extending more than 25 nautical miles (more than 46 kilometers) off the glacier’s face.
For senior acoustician Alison Herbert and scientific systems engineer Tom Rushton Brumby, this is the second time they have discovered an impressive feature on the Antarctic seafloor using the ship’s acoustic instruments.
“This latest mapping adds to our initial discovery two years ago, on Noina’s first trip to Casey, when we mapped the nearby Vanderford Valley, which is 2,200 meters deep, 2,000 meters wide and at least 55 kilometers long,” Ms Herbert said.
“Nuyina’s multibeam echosounder gives us a much greater ability to map the seafloor in detail than ever before, and these two new discoveries suggest there will be more to come.”
The acoustics team initially explored the southern end of the valley before the ship had to return to Casey for shipping operations.
Expedition leader Keith Ashby said that fortunately, bad weather enabled the ship to return to the area a few days later, where further observations were carried out in very difficult conditions.
“Four-meter waves and 50-knot winds hampered our resupply operations at Casey, so we decided to brave the weather in open water, allowing our acoustics team to conduct about 15 hours of mapping in front of Adams Glacier,” Mr Ashby . He said.
“Then on our way back to Australia, we made another fleeting visit to fill in some of the remaining gaps, resulting in a comprehensive picture of this deep glacial basin.
“Since the flight was primarily to resupply the station, the fact that we got any opportunity to complete some seafloor mapping was really exciting. Discovering a feature as substantial as the Grand Canyon was really exciting.”
Nuyina’s multibeam echosounder works by sending fan-shaped acoustic sounds below the ship and “listening” to the returning echoes to create an image of the seafloor.
“I always find it amusing, almost magical, to make one rainbow path of the seabed one ping after another,” Ms Herbert said.
Among other things, seafloor maps created using multibeam echosounder data provide insight into the geological and glacial history of the area and allow scientists to identify areas for further study.
Lloyd Simons, RSV Nuyina’s technology director, said the vessel rose to the challenge for which it was designed.
“One of the stated goals in building RSV Nuyina was to provide Australia with the ability to map the Antarctic continental shelf,” May-Simmons said.
“Discovering and mapping these deep ice grooves is key to developing better models of the interaction between the Antarctic ice sheet and the ocean. This is just the beginning.”