Each year about 4.8 to 12.7 million tons of plastic enter the sea. This might affect the marine ecosysteme and marine organisms. Information on presence, amount and composition of marine litter helps to develop strategies on litter reduction.
The three Thünen fishery institutes collect data on marine litter at the sea floor since years. Litter items catched in bottom trawls are classified using the international standardized international protocol. Most litter items are plastic such as sheets, fishing lines and fishing nets. Also glass and metal litter items were collected - sometimes even an old shoe. Plastic litter can be dangerous for marine organisms if they are entangled or swallow the litter blocking their digestive tract. Data on marine litter are part of the environmental assessment as demanded by MSFD.
Another research topic is microplastic. It can enter the sea directly e.g. as cosmetic ingredient via waster (primary microplastic) or arise from bigger plastic litter items by breakdown (secondary microplastic). Fish can mistake microplastic for food and swallow it. Effects of microplastic on fish have been investigated in the reserach project PlasM.