A new study published in the journal Marine Pollution Bulletin reveals that the amount of plastic debris and litter on the Arctic Ocean’s sea floor has doubled in the past 10 years. Dr. Melanie Bergmann, the study’s lead author and a biologist at the Alfred Wegener Institute for Polar and Marine Research (AWI), observed some 2,100 deep-sea photographs taken between Greenland and the Norwegian island of Spitsbergen from 2002-2011 and found that not only had plastic pollution doubled in this region within the last decade, but that 70% of the plastic litter had come into contact with deep-sea organisms, including plastic bags entangled in sponges, sea anemones settling on pieces of plastic or rope and cardboard and a beer bottle colonized by sea lilies.
“The Arctic Ocean and especially its deep-sea areas have long been considered to be the most remote and secluded regions of our planet,” said lead author Dr. Melanie Bergmann. “Unfortunately, our results refute this notion—at least for our observatory.”
Annual deep-sea photographs are generally used by the AWI to record changes in biodiversity, but when Bergmann reviewed images taken in 2011, she discovered a notable surge in plastic pollution on the sea floor: “When looking through our images, I got the impression that plastic bags and other litter on the sea floor were seen more frequently in photos from 2011 than in those dating back to earlier years. For this reason I decided to go systematically through all photos from 2002, 2004, 2007, 2008 and 2011.”
Though the exact origin of the plastic garbage in the Arctic Ocean is unknown, Bergmann suspects that it stems from the shrinking and thinning of the Arctic ice, which has prompted a substantial increase in both commercial and private ship traffic within the area. “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,” Bergmann noted. “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.”
The rise in plastic pollution is expected to affect sea floor inhabitants in numerous ways, including hindering their ability to absorb food particles, which may result in stunted growth and diminished reproduction. Plastic accumulation on the sea floor could also accumulate through the food chain and be ingested by marine animals, including commercially harvested prawns and fish. It could even deprive the water of oxygen.
“Other studies have also revealed that plastic bags that sink to the sea floor can alter the gas exchange processes in this area. The sediment below then becomes a low oxygen zone, in which only few organisms survive,” Bergmann reported, adding: “Pieces of plastic on the deep sea floor are unlikely to degrade into micro-plastics as quickly—as is the case on the North Sea coast. This is due to the lack both of sunlight at a depth below 200 meters and of strong water movement. Under these conditions, plastic waste can probably persist for centuries.”