Plastic waste discovered in deep underwater canyon off Irish coast

29 Jul 2019

White plastic sack at the bottom of the Porcupine Bank spotted by underwater cameras. Image: UCC

The scourge of plastic waste has reached new depths, quite literally, with the discovery of waste at the bottom of a deep underwater canyon.

Despite being located 320km off the coast of Dingle, a deep underwater canyon is acting as a rubbish bin for plastic waste. The discovery was made by researchers from University College Cork (UCC) who have been investigating cold-water coral habitats in the Porcupine Bank canyon on an expedition aboard the RV Celtic Explorer.

The mission included eight monitoring stations called ‘landers’, deployed between 2,500 metres and 700 metres deep in the Atlantic Ocean. However, members of the team were disturbed to see that at 2,125 metres down in the canyon – equating in height to 10 Eiffel Towers stacked on top of one another – was plastic waste.

“It’s always sad to see plastic rubbish in these otherwise pristine habitats. It [is] quite incredible that our plastic waste can get this far out and so deep in the oceans,” said UCC’s Prof Andy Wheeler, who has conducted research on cold-water coral mounds off the coast of Ireland over the past 20 years.

“I don’t think people think about this when they 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.”

Map of Ireland and Porcupine Bank with a red dot showing where the plastic was found.

The red dot indicates where in the Porcupine Bank the plastic waste was found. Image: UCC

Aside from discovering the plastic waste, the research team did also make some important scientific breakthroughs in the vast stretch of canyon.

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

The research is part of an ongoing effort to monitor how changing environments and microplastics are affecting the cold-water reefs located between 600 metres and 1,000 metres along our continental margin.

Other researchers have raised alarm bells over the amount of plastic waste in oceans, with some predicting that by 2050 there will be more plastic by weight in the world’s oceans than fish.

Colm Gorey was a senior journalist with Silicon Republic