Bremerhaven, April 30, 2014. An international team of researchers has, for the first time ever, conducted a wide-ranging survey of litter in European waters and has found traces of waste in every region – from coastal areas all the way down to deep canyons. The results of this survey appeared on May 1 in PLOS ONE, a peer-reviewed, online journal. How this litter affects marine life and, ultimately, human beings, is largely unknown to date.
“We were quite surprised to see the extent to which our litter has already spread in the oceans. We found litter even in remote regions such as the Arctic and the Mid-Atlantic Ridge. It is a gloomy perspective that virtually every camera deployment or trawl shows litter. It appears that our waste actually reached these hitherto unknown areas of the earth long before we did,” says Dr. Melanie Bergmann.
The marine biologist from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, played an active part in the current study. Led by Christopher Pham ( University of the Azores), she cooperated with scientists from fifteen different European research institutions to compile data as to how much litter is present in European waters. This consortium used bottom trawls, video recordings and photographs to assess the amount of litter present in 32 different marine regions in the Northeast Atlantic, Arctic Ocean and Mediterranean.
In conducting the study, the scientists analysed 588 video recordings and trawl surveys for signs of litter. Some samples came from shallow coastal waters, others from depths exceeding 4,500 meters. It is the first study on litter on the seafloor to cover such a great range of habitats.
The researchers found litter everywhere: near the coasts, on the continental shelf, in deep-sea , and right down into the canyons. The largest quantities were found near densely populated population centres – and in deep-sea canyons. In some cases such canyons connect the shallow coastal waters with the abyssal plain such that they may enable the downward transport of litter from the coasts into distant, deeper waters.
The items recorded included abandoned fishing gear, glass bottles, and metal. “The kind of litter we detected most frequently was plastic,” says lead author Christopher Pham. The scientists found plastic in almost half of the videos and in nearly all trawls. Where larger pieces of plastic accumulate researchers also suspect the presence of micro plastics because the plastics degrade into smaller fragments over time, with unknown consequences for the environment. “It is with these particles, just millimetres in size, that ecological problems probably really start. Micro plastics are more easily consumed by animals and can accumulate within the food chain. Unfortunately, various toxins readily adsorb onto the hydrophobic surface of micro plastics in the ocean and they may then also accumulate within the food chain,” explains Dr. Melanie Bergmann. Microplastics have already been detected in some North Sea fish, shrimps and Norway lobsters. But these signs are presumably only the tip of the iceberg.
Plastic litter has already reached the Arctic, Dr. Melanie Bergmann concluded after analysing almost three thousand photographs taken by a towed camera system at the HAUSGARTEN – the deep-sea observatory operated by the Alfred Wegener Institute in the eastern Fram Strait. Like in other European waters, the marine biologist found plastic litter in the strait between Greenland and Spitsbergen (see press release dated October 22, 2012).
The AWI scientists beat this sad European depth record already in 1999 when they sighted litter in camera deployments at 5500m depth in the Molloy Hole – the deepest station of HAUSGARTEN and the deepest known point in the Arctic Ocean.
The scientists do not yet know how litter spreads across the seas. Ocean currents, topographic features and increasing ship traffic certainly play an important role. Plastic, in particular, owing to its longevity and its low weight, can be carried over long distances by marine currents such that they reach areas as remote as the Mid-Atlantic ridge or the Arctic. In the Arctic, the receding sea ice has probably enabled more litter reaching the far north as ship traffic increases locally.
And so the pressing questions are: How much litter is there hidden on the oceans’ floors and how does it affect marine organisms? Scientists know that animals such as sea birds and marine mammals confuse litter with food and that they become entangled in derelict fishing gear. But next to nothing is known about the effects of litter on residents of the (deep) seafloor.
Projects like this completed European study are crucial to raise public awareness of this problem. “Such studies are extremely relevant for political decision-makers. The European Union set out grand goals in its Marine Strategy Framework Directive as it committed to evaluate the condition of European waters and to define what ‘good environmental status’ of the oceans is. Litter contamination is explicitly mentioned in this directive,” explains Dr. Melanie Bergmann.
This summer, the deep-sea researchers of the Alfred Wegener Institute plan to take sediment samples at HAUSGARTEN to assess if microplastic particles have invaded this area in close collaboration with colleagues from AWI Heligoland.
The current study was initiated under the leadership of the University of the Azores and is one result of HERMIONE (Hotspot Ecosystem Research and Man’s Impact on European Seas), a project funded by the EU and in which European research institutions how human activities affect the ecosystems in the deep seas. Another German institute, which contributed to the current study was the Jacobs University in Bremen.
Notes for Editors:
The original paper was published on April 30th 2014 under the following title in the online journal PLOS ONE: Marine litter distribution and density in European Seas, from the shelves to deep basins. Follow the link to read the paper: http://dx.plos.org/10.1371/journal.pone.0095839
Your contact persons are Dr. Melanie Bergmann (tel.: 0049 471 4831-1739, e-mail: Melanie.Bergmann(at)awi.de) and Kristina Baer, Dept. of Communications and Media Relations (tel.: 0049 471 4831-2139; e-mail: kbaer(at)awi.de).
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The Alfred Wegener Institute 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.