Trash increasingly litters Arctic seabed: study
"Plastic waste can probably persist for centuries"
The seabed under the Arctic ocean is increasingly strewn with litter and plastic, says a new study published in the Marine Pollution Bulletin.
For her study, Dr. Melanie Bergmann examined some 2,100 seabed photographs taken in the eastern Fram Strait between Greenland and the Norwegian island of Spitsbergen near the deep-sea observatory of Germany’s Alfred Wegener Institute.
Bergmann found these photos show evidence that deep-sea plastic pollution doubled from 2002 to 2011.
On their way to the observatory, scientists regularly drag a towed camera system from their ship. The camera goes down 2,500 metres, 1.5 metres above the seabed, and takes a photo every 30 seconds.
Biologists mainly use these photographs to document changes in deep-sea life like sea cucumbers, sea lilies, sponges, fish and shrimps.
But as she studied the photos, Bergmann found twice as many photos taken in 2011 showed deep-sea trash.
Almost 70 per cent of the plastic litter had also come into some kind of contact with deep-sea organisms.
“We found plastic bags entangled in sponges, sea anemones settling on pieces of plastic or rope, cardboard and a beer bottle colonised by sea lilies,” Bergmann said in an Oct. 23 news release from the institute.
The plastic could injure deep-sea creatures like sponges, preventing them from aborbing nutrients or impairing their breathing, she said.
The trash could also encourage other forms of deep-sea life to use the waste to settle on, changing the seabed environment..
Bergmann was unable to determine the origin of litter from the photos.
But she said she suspects that the shrinking and thinning of the Arctic sea ice, along with the increase in marine traffic, may explain why plastic trash is accumulating in the Arctic.
“The Arctic sea ice cover normally acts as a natural barrier, preventing wind blowing waste from land out onto the sea, and blocking the path of most ships. Ship traffic has increased enormously since the ice cover has been continuously shrinking and getting thinner. We are now seeing three times the number of private yachts and up to 36 times more fishing vessels in the waters surrounding Spitsbergen compared to pre-2007 times,” she said.
Plastic sea trash is likely to stick around for a long time due to the lack of movement and sunlight below 200 metres, she said.
“It is dark and cold there. Under these conditions plastic waste can probably persist for centuries,” Bergmann said.