Researchers discover coral ‘living on the edge’ off Irish coast

10 Nov 2020

Cold-water coral has been found to survive in extreme conditions off the coast of Ireland. Image: UCC/Marine Institute

UCC researchers exploring Ireland’s largest underwater canyon have found coral surviving in extreme conditions.

The durability of cold-water coral has been revealed in a recent discovery made by a team of University College Cork (UCC) and Marine Institute scientists. The team, led by Dr Aaron Lim, was exploring the Porcupine Bank Canyon – Ireland’s largest submarine canyon off the island’s west coast.

Up to 3,500 metres deep, the canyon was explored using the remotely operated vehicle Holland 1 launched from the RV Celtic Explorer vessel. It found that cold-water coral in this canyon can survive at current speeds of up to 114cm per second, the highest speed ever recorded in a cold-water coral habitat.

“These cold-water corals are growing at the very edge of a near-vertical cliff face in Ireland’s largest submarine canyon, some 850 metres below the surface, in very intense conditions,” Lim said. “They’re quite literally living on the edge.”

Cold-water corals help form deep-water reefs and mounds, which can range in height from 10 metres to more than 100 metres. The Porcupine Bank Canyon is a rich source of these natural structures and some of these mounds date back as far as 2.6m years ago.

As part of the study – the findings of which have been published to Nature – the team was looking to understand why some cold-water coral habitats were predominantly alive, while others were found to be mostly dead.

A remote monitoring device placed by the UCC team on the ocean floor.

One of the remote monitoring devices placed by the UCC and Marine Institute team. Image: UCC/Marine Institute

A ‘deep, dark and cold’ world

Using Holland 1, the team collected data on the coral habitats and reconstructed them in 3D to better understand how deep-water currents were affecting them.

UCC marine biologist Luke O’Reilly said the canyon is “a strange-place; deep, dark and cold, but full of life”.

“This submarine canyon is so deep and complex and, together with the Marine Institute, we developed a monitoring system which could withstand these pressures and conditions for months at a time,” O’Reilly added.

Commenting on the recent findings, Prof Andrew Wheeler, head of the School of Biological, Earth and Environmental Sciences at UCC, said: “Interestingly we found that while the corals can survive these extreme conditions, it appears that they favour when the current slows down, such as when the tide turns, and this is likely when they feed.”

The team recently deployed more monitoring stations that will gather data over the next year to see how the corals will respond to these conditions over a longer time frame.

Colm Gorey was a senior journalist with Silicon Republic