Denman Marine Voyage: long-term vision now a reality

Accessing the vast and remote Denman Glacier system in Australian territory in East Antarctica by ocean is a monumental task, and after many years of planning and collaboration it’s now a reality.

The Denman Marine Voyage (DMV) – the maiden marine science voyage of RSV Nuyina – departed Hobart on March 1, 2025 and is expected to reach the Shackleton Ice Shelf and Denman glacier area in coming days.

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Getting to the Denman Glacier was a core element of the original proposal for the Australian Centre of Excellence for Antarctic Science (ACEAS) in 2019, says Director, Professor Matt King.

Australia’s new state-of-the-art icebreaker was coming online, he said, presenting an opportunity to get into what had traditionally been one of “the very tricky places.”

“You have to break a lot of sea ice to get there, in order to make the measurements of the ocean and beneath the ice and the ecosystems,” said Professor King.

“We saw the need and there was the opportunity provided by Nuyina, so we thought we need to get in there and do that.”

It’s now several years since ACEAS came into being, and 60 scientists from four scientific partner organisations – ACEAS, AAPP, SAEF and the AAD – are on board the DMV in a major research collaboration.  

“We are looking forward to studying how the glacier and ice shelf are changing the nearby ocean and vice versa.” says ACEAS Science Coordinator Professor Delphine Lannuzel.  

“The Denman Glacier and the Shackleton Ice Shelf next to it are interesting areas because it’s really that transition zone between the land and the ocean. We’re looking at the drivers of change as well as the impacts of those changes on the local ecosystems, both in the water and on the seafloor. ”

The DMV follows the land-based Denman Terrestrial Campaign (DTC), carried out over recent summers around the glacier in the Bunger Hills in East Antarctica. The DMV bridges the two missions together.

“It’s an area that’s sensitive to changes. We know that the glacier is losing ice and  the grounding line – that’s the area where the ice sheet meets the seafloor – is eroding away.”

The Denman Glacier has long stood out because of its “massive sea level rise potential – one and a half metres of global sea level rise if it was to melt entirely,” said Professor King.

“It’s worth pausing and thinking – what is one and a half metres of global sea level rise?” he said.

“If you stood at the edge of the ocean and looked out over the Pacific Ocean or the Indian Ocean and thought, what would it take to raise this ocean by one and a half metres? – well, that’s the Denman Glacier, just on its own.”

Professor King said while the glacier would take a lot longer than the next centuries to melt, very little was known about it.

“So the potential of it, combined with a lack of knowledge about it, lead us to say “actually, we need to understand this and we need to understand it from on the ice and around the ice, but also from the ocean side,” he said.

“It’s the ocean that’s the enemy of Antarctica. The air is so cold that you would need to warm the atmosphere by five or six degrees to have a large -scale surface melting.”

“But the ocean… you only need to turn the knob by a fraction of a degree to actually melt the ice faster and to cause it to flow faster, and to drive up sea level and to have more fresh water in the ocean. That disrupts the circulation of the ocean, which changes ecosystems.”

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Professor Lannuzel said traditionally, much of the focus on the melting Antarctic ice sheet has been on the western hemisphere side, and the east “was considered a sleeping giant. This perspective has been challenged in recent years.”

“The Denman is almost like a plug. If you pull it, then the rest of the East Antarctic ice sheet can start to flow into the ocean,” she said.  

“Antarctica is not out of sight, out of mind. It does have an impact on our day-to-day lives in Australia.”

“We’re proud of the work that we do and look forward to reporting back to Australians about what we’ve observed during the campaign, and how it may impact them.”

The DMV is part of the Australian Antarctic Program (AAP). The RSV Nuyina will return to Hobart in early May 2025.