The OFOS captures several hundred images in a single transect. Meticulously, these are analysed by Bergmann and her team when back at the AWI. Normally, the marine biologist scans the images for signs of larger bottom-dwelling organisms such as sponges, sea cucumbers or fish inhabiting the bottom of the Fram Strait – the waters between east Greenland and Svalbard. This part of the world is home to the HAUSGARTEN observatory, which is part of the FRAM infrastructure.
It is monitored year-round by measuring devices such as sediment traps and flow sensors which are moored or fitted to benthic landers. In addition, the HAUSGARTEN stations are visited and sampled every year with the research icebreaker Polarstern.
For some time now, however, Bergmann’s attention has been diverted from the animals of HAUSGARTEN to something quite different: the litter lying on the ocean seafloor. “At some point I got the feeling that the images revealed more and more rubbish every year. I then began to scan several thousand images from our archive, and investigated marine litter during my expeditions.”
The findings are clear: between 2002 and 2011 the amount of litter and debris lying on the ocean floor in one square kilometre of the HAUSGARTEN 2,500 metres beneath the sea surface more than doubled, rising from ca. 3,600 to 7,700 pieces. Plastic bags, glass bottles, and tangled bits of old fishing nets – there is a variety of trash to choose from.
“We can still only guess where it all comes from,” says Bergmann. It may be transported to the Arctic from the more populated North Atlantic; or it could be from the ships that are now venturing farther and farther northwards as the Arctic’s sea-ice cover recedes. “Unlike in the past, we can sometimes hear fishers on the radio. And we now find fishing nets here – which tells us the trawlers are now following the Atlantic cod farther north.”