Plastic found 2,125m below off Irish coast

Plastic waste has been found at the bottom of a deep submarine canyon by UCC scientists who are investigating cold-water coral habitats.

UCC’s Marine Geology Research group returned on Monday after investigating in the Porcupine Bank Canyon, some 320km due west of Dingle, on a research expedition led by UCC’s Dr Aaron Lim on board the Marine Institute’s RV Celtic Explorer.

The researchers found plastic in the bottom of the canyon, deep enough that you could stack ten Eiffel Towers inside, at 2,125m water depth.

“It’s always sad to see plastic rubbish in these otherwise pristine habitats. It quite incredible that our plastic waste can get this far out and so deep in the oceans,” said UCC Professor Andy Wheeler, who has pioneered research on cold-water coral mound offshore Ireland over the past 20 years.

“I don’t think people think about this when that dump their rubbish. We’re also trying to see if microplastics are being fed to the corals from above.

“We’ve just got the samples, let’s hope we’re wrong.”

The Porcupine Bank Canyon is teeming with a whole range of cold-water coral habitats, just on Ireland’s doorstep, according to Dr Lim.

The group has recovered eight novel monitoring stations called ‘landers’ worth €450,000, deployed between 2500m water depth and 700m water depth by the Marine Institute’s Remotely Operated Vehicle (ROV) Holland 1 earlier this summer.

The monitoring stations record the speed, temperatures and direction of the currents around these habitats as well as trapping samples of the food, sediments and microplastics being deposited around the corals to understand conditions down there and how the corals are coping with changing oceans.

Dr Lim added: “The environment is much more dynamic than we thought, with two of the monitoring stations knocked over by the currents, food supply for the coral is variable but the corals are doing okay.

“Some of these habitats have existed for millions of years and have grown so large they resemble hills made of coral, called coral mounds,” he added.