Australian icebreaker Aurora Australis has returned from Antarctica with new information about marine life under the world's largest ice sheet.
More than 50 researchers from eight countries - including New Zealand - have spent the past two months on board.
In one project, they use an underwater robot to record more than 40 hours of vision of life under the East Antarctic ice sheet.
The voyage was not without problems, with ice freezing over late last month, leaving scientists stuck for 11 days.
In some parts the ice was 20 metres thick.
The crew eventually used helicopters to guide them back to the open sea.
Antarctic Division director Tony Fleming would not be drawn on the cost of the delay but says the extra time at sea brought research benefits.
"The delay aided the scientists because they were able to much more science and much more detailed science at a particular ice station," he said.
"So it didn't affect the science that could get done, in fact, it really aided their scientific investigations."
Modelling predicts sea ice in Antarctica could decline by 35% by the end of the century.
The scientists say their research will be useful in determining whether recent dramatic changes in ice conditions on the West Antarctic Peninsula are mirrored on the eastern side.
They have also collected valuable information about the distribution of sea ice algae and krill populations living up to 20 metres beneath the ice surface.
The Aurora Australis is being restocked and will head south again for Australia's Davis Station in the next few days.