The Alfred Wegener Institute (AWI) has been studying trash on the Arctic seabed since 2002, visiting two dozen sites in the Fram Strait every year to collect samples and photographs. The center's 15 years of data have just been published in the journal Deep-Sea Research, and the results are not encouraging.
"Our time series confirms that litter levels in the Arctic deep sea have risen rapidly in the past few years,” says lead author Mine Tekman. The team used a towed camera system to look at the ocean floor between Svalbard and Greenland, and they found an average of more than 16,000 pieces of trash per square mile. The average was quite a bit lower in years past – just short of 9,000 pieces per square mile – but it showed a steady increaase from 2011-2014. At one sampling station, the contamination level was nearly 21,000 pieces per square mile, making it among the most litter-filled areas of the deep sea.
Much of the trash is made of plastic, and while researchers are finding more small, degraded pieces in recent years, they also see evidence that the Arctic deep is a good place for preserving plastic intact – raising the possibility that the trash pile will grow. They even saw one piece twice in two years, and found that it still looked about the same. "Running into this same piece of plastic twice with hardly any changes to it is a vivid reminder that the depths of the Arctic are at risk of becoming a depot for plastic litter. The well-hidden accumulation of litter on the deep ocean floor could also explain why we still don’t know where 99 percent of the marine plastic litter ends up," said co-author Dr. Melanie Bergmann.
The scientists believe that much of the plastic is carried north and east by the Gulf Stream, with possible contributions from a gyre system in the Barents Sea. Additionally, the team hypothesizes that much of the litter that finds its way onto the seafloor off Svalbard may come from melting icebergs: it is possible that it may be getting trapped in the ice up north, then floating south with the bergs during the spring breakup.