Diving to depths of 600 metres (1,970ft), to the summit of a previously unmapped seamount in the central part of the archipelago, the scientists witnessed a breathtaking mix of deep marine life. This has raised hopes that healthy reefs can still thrive at a time when coral is in crisis due to record sea surface temperatures and ocean acidification. It also showed the effectiveness of conservation actions and effective management, they said.

“They are pristine and teeming with life – pink octopus, batfish, squat lobsters and an array of deep-sea fish, sharks and rays,” said Dr Michelle Taylor, a marine biologist at Essex University and co-leader of the expedition in a human-occupied vehicle, HOV Alvin, a submersible able to take two scientists to depths of 6,500 metres.

The find shows that sheltered deep-water coral communities have probably persisted for centuries in the depths of the Galápagos marine reserve, supporting rich, diverse and potentially unique marine communities.

“These newly discovered reefs are potentially of global significance – a ‘canary in the mine’ for other reefs globally – sites which we can monitor over time to see how pristine habitats evolve with our current climate crisis,” Taylor said.

Banks said the reef helped scientists “reconstruct past ocean environments to understand modern climate change”. It could also help understand the role of MPAs in the carbon cycle and fisheries. “It’s very likely there are more reef structures across different depths waiting to be explored,” he said.