The search for Antarctic explorer Sir Ernest Shackleton's lost Endurance ship has been called off, after extreme weather trapped an underwater vehicle in a sheet of frozen ice.
Severe weather closed in and the sea ice conditions led to the loss of the AUV7, a specialist submersible autonomous underwater vehicle, which was deployed to locate the wreck using HD still colour cameras.
The Weddell Sea Expedition team was on the final leg of the mission when the vehicle entered underneath a vast sheet of floating ice to take images of the legendary ship but contact was lost with the Expedition research vessel, the S.A. Agulhas II.
Despite efforts to recover the AUV7, the team decided to abandon the mission due to risks of becoming themselves trapped in the ice.
Any captured footage that may have been of Endurance on the seabed was lost.
The AUV7 had conducted what is believed to be the longest and deepest dedicated under ice survey ever, lasting over 30 hours.
Dr John Shears, polar geographer and expedition leader, said: "The Weddell Sea Expedition team are truly disappointed that after such a huge effort, and overcoming several major setbacks, we have not been able to find Endurance.
"We are, however, very proud of our other achievements over the past weeks in Antarctica.
"We have greatly surpassed our primary Expedition objective of undertaking pioneering scientific research at the Larsen C Ice Shelf.
"We have also conducted an unprecedented educational outreach program, allowing children from around the world to engage in real time with the expedition and our adventures from the outset.
"The expedition team, and the officers and crew of the S.A. Agulhas II, have been simply outstanding."
Sir Ernest Shackleton's ship, Endurance, was crushed by ice and sank in 1915.
The search for Endurance was part of a ground-breaking scientific research program in the waters around the Larsen C Ice Shelf and the A-68 Iceberg in Antarctica.
The international team of glaciologists, marine biologists and oceanographers involved in the Expedition have surveyed the sea floor and the rich and little-studied biological systems that lie beneath the ice infested sea.
Mensun Bound, director of exploration on the expedition, said: "As a team we are clearly disappointed not to have been successful in our mission to find Endurance.
"Like Shackleton before us, who described the graveyard of Endurance as 'the worst portion of the worst sea in the world', our well laid plans were overcome by the rapidly moving ice, and what Shackleton called 'the evil conditions of The Weddell Sea'.
Shackleton's attempt to cross Antarctica began in 1914.
After the vessel became trapped in ice for 10 months and then sank, the explorer and his crew survived for six months before reaching uninhabited Elephant Island.
Shackleton and five other men then set off to seek help at a whaling station on the island of South Georgia.
After three unsuccessful attempts, Shackleton finally rescued his men in August 1916.
The Weddell Sea Expedition team says it may attempt the mission again.
