Sea ice could be responsible for transporting plastic litter
The Arctic has a serious litter problem: in just ten years, the concentration of marine litter at a deep-sea station in the Arctic Ocean has risen 20-fold. This was recently reported in a study by researchers at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).
Plastic bags, glass shards and fishing nets: despite its location, far from any urban areas, the amount of litter in the depths of the Arctic Ocean continues to rise, posing a serious threat to its fragile ecosystem. Since 2002, AWI researchers have been documenting the amount of litter at two stations of the AWI’s “Hausgarten”, a deep-sea observatory network, which comprises 21 stations in the Fram Strait, between Greenland and Svalbard.
The results of the long-term study have now been published in the scientific journal Deep-Sea Research I. “Our time series confirms that litter levels in the Arctic deep sea have risen rapidly in the past few years,” says first author and AWI biologist Mine Tekman.
The scientists involved in the study observed the ocean floor at a depth of 2,500 metres using the OFOS (Ocean Floor Observation System), a towed camera system. Since the start of their measurements, they have spotted 89 pieces of litter in a total of 7,058 photographs. To enable comparison with other studies, the researchers have extrapolated the litter density to a larger area.
The result: an average of 3,485 pieces of litter per square kilometre in the monitoring period (2002 to 2014). Further, there has been a clearly recognizable increase in the past few years: when the team calculated a contamination level of 4,959 pieces of litter per square kilometre for 2011 in an earlier study, they hoped it was a statistical outlier. But the levels have continued to rise since, reaching a new peak of 6,333 pieces of litter per square kilometre in 2014.
The situation is particularly dramatic at the network’s northern station, called N3. “Here the amount of litter rose more than 20-fold between 2004 and 2014,” says Tekman. If we consider the findings for the northern research area in the marginal ice zone, the data for 2004 indicated 346 pieces of litter per square kilometre. Ten years later, the number had risen to 8,082. The level of contamination is similar to one of the highest litter densities ever reported from the deep seafloor, in Cap de Creus Canyon off the eastern coast of the Iberian Peninsula.
Among the litter they photographed, the researchers observed plastic and glass most frequently. As a rule, glass does not drift; it sinks straight down to the ocean floor. This indicates local sources and concurs with increasing ship traffic in the region due to the receding ice. Still, it is extremely difficult to draw any firm conclusions on the origin of the plastic litter, since it often covers a considerable distance before reaching the seafloor. In most cases, the scientists can’t determine the origin on the basis of photographs alone.
While it is clear that the Gulf Stream transports plastic litter into the Arctic with the Atlantic water masses, the authors also have a new theory as to why litter is accumulating in the Fram Strait: their results indicate a positive relationship between litter density and the summertime expansion of sea ice. “If we’re right, sea ice could entrain floating litter during ice formation. During warmer periods, the ice breaks up and is transported to the south into the Fram Strait with the Transpolar Drift, releasing entrained litter into the survey area when it melts,” says deep-sea biologist Dr Melanie Bergmann, a co-author of the study. “To date we’ve assumed just the opposite, since we viewed the ice as a barrier to litter contamination.”
The researchers are still faced with the puzzle of when and how plastic litter changes on its way to the deep sea. Over time they have observed more and more small bits of plastic, which are likely the result of larger pieces of litter fragmenting and could point to an increasing level of microplastic. This is surprising, since in the deep sea there is no UV light to break down the plastic, and the low temperatures are not conducive to disintegration. In the summer of 2016 the team rediscovered a piece of plastic, which they had first seen two years earlier. Bergmann: “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% of the marine plastic litter ends up.”
More information on the AWI Hausgarten and the OFOS camera system:
The Hausgarten is the AWI’s deep-sea observatory in the Fram Strait, and currently consists of 21 stations at depths ranging from 250 to 5,500 metres. Samples have been collected at these stations every summer since 1999. Further, the year-round operation of moorings and free-falling lander systems, which serve as observation platforms on the seafloor, makes it possible to record seasonal changes. With the help of an ROV (Remotely Operated Vehicle), samples are collected at regular intervals, automatic recording instruments are positioned and maintained, and in-situ experiments are conducted. The Hausgarten represents one of the key regions in the European Network of Excellence ESONET (European Seas Observatory Network) and is part of Germany’s Long Term Ecological Research network (LTER-D).
During Polarstern expeditions to the Hausgarten, deep-sea researchers at the Alfred Wegener Institute regularly employ the remotely controlled towed camera system OFOS (Ocean Floor Observation System). At four Hausgarten stations its cameras are suspended roughly 1.5 metres above the seafloor at a depth of 2,500 metres, where they take a photograph every 30 seconds. These photographs enable deep-sea biologists to document changes in the species diversity for larger forms of sea-life, for example in sea cucumbers, sea lilies, sponges, fish and shrimps.
Notes for Editors:
• Mine B. Tekman, Thomas Krumpen, Melanie Bergmann: Marine litter on deep Arctic seafloor continues to increase and spreads to the North at the HAUSGARTEN observatory. Februar 2017. DOI: 10.1016/j.dsr.2016.12.011; Link:
Please find printable images in the online version of this press release: http://www.awi.de/nc/en/about-us/service/press.html
Your scientific contact persons are:
Dr Melanie Bergmann
tel.: +49 (0)471 4831-1739
Mine B. Tekman
tel.: +49 (0)471 4831-2130
Your contact person at the Dept. of Communications and Media Relations is:
tel.: +49 (0)471 4831-2006
The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.
Ralf Röchert | idw - Informationsdienst Wissenschaft
Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
Understanding animal social networks can aid wildlife conservation
23.06.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Agricultural and Forestry Science
26.06.2017 | Life Sciences
26.06.2017 | Health and Medicine