Arctic sealife under threat amid record levels of litter
November 01 2012 Lewis Smith
One of the world’s most pristine seabeds is becoming contaminated with litter which has doubled in quantity in a decade, researchers have warned.
Photographs have revealed that in 2011 twice as much rubbish was strewn over the Arctic seabed in a deep water area between Spitsbergen and Greenland than it was in 2002.
Plastics are among the most commonly found types of litter and fishing vessels are suspected of being responsible for the majority of items.
Despite being in such a remote area there was more litter found on the Arctic seabed than in a deep sea canyon off Libson, the industrialized Portuguese city in a part of the world long frequented by shipping.
The findings were made in a study by Dr Melanie Bergmann, of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association, Germany, after a she had a hunch that litter was more prevalent.
She looked at 2,100 photographs from a deep sea camera system used at Hausgarten in the Eastern Fram Strait and found that litter could be seen in two per cent of the images taken in 2011, compared to one per cent in 2002.
"The study was prompted by a gut feeling. When looking through our images I got the impression that plastic bags and other litter on the seafloor were seen more frequently in photos from 2011 than in those dating back to earlier years,” she said.
"Waste can be seen in around one percent of the images from 2002, primarily plastic. In the images from 2011 we made the same discovery on around two percent of the footage. The quantity of waste on the seabed has therefore doubled.
"The Arctic Ocean and especially its deep-sea areas have long been considered to be the most remote and secluded regions of our planet. Unfortunately, our results refute this notion at least for our observatory. The quantities observed were higher than those recorded from a deep-sea canyon not far from the industrialised Portuguese capital Lisbon."
Fishing vessels are suspected of being behind the litter because they are much more common in Arctic waters and because most litter washing up on beaches on Spitzbergen are from fisheries.
Dr Bergmann said: "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.”
The fear is that plastic and other rubbish on the Arctic seabed will interfere with the ecosystem and change it. Animals in the region which injest chemicals from plastic, which has a range of toxic effects, might be able to absorb less food, grow more slowly or reproduce less successfully.
“Almost 70 percent of the plastic litter that we recorded had come into some kind of contact with deep-sea organisms. For example 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,” said Dr Bergmann who reported her findings in the journal Marine Pollution Bulletin.
“Other studies have also revealed that plastic bags that sink to the seafloor can alter the gas exchange processes in this area. The sediment below then becomes a low oxygen zone, in which only few organisms survive.”
In contrast, animals from outside the region are able to use litter as a hard surface to settle on: “This allows colonisation by species that previously would have found hardly any suitable substratum. This means that the waste could change the deep-sea composition of species and therefore biodiversity in the long-term.”
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