The BAS said that an iceberg known as A68 broke off from the Larsen Ice Shelf in July 2017, revealing a section of seabed measuring 5,818 square kilometres (2,245 square miles) — nearly four times the size of London.
“It is an urgent mission. The ecosystem that’s likely been hidden beneath the ice for thousands of years may change as sunlight starts to alter the surface layers of the sea,” BAS said in a statement.
The international team left Stanley in the Falkland Islands and will spend three weeks on board the BAS research ship RRS James Clark Ross.
The BAS signalled the start of the mission in a tweet saying: “And they’re off!”, accompanied by a video from the ship leaving the Falklands.
The South Atlantic islands, known in Spanish as Malvinas, are disputed between Argentina and Britain.
BAS marine biologist Katrin Linse, who is leading the mission, said it was “a unique opportunity to study marine life as it responds to a dramatic environmental change”.
The team will explore the seabed by collecting seafloor animals, microbes, plankton, sediments and water samples. They will also record marine mammals and birds who may have moved into the area.
Environmental group Greenpeace last month visited the Antarctic seafloor in a submarine and captured alien-like images of the previously unexplored underwater world.
The Greenpeace expedition was part of a campaign to turn a large section of the region into the world’s biggest ocean sanctuary.