The Fram Strait is the only deep passage between the North Sea coast of Greenland and the Artic islands of Spitzbergen. It provides for the exchange of oxygen-rich water masses. The eastern part transports warm Atlantic water north while the western part carries sea ice and frigid water in the opposite direction southwards. This combination of circumstances is considered to be the reason why the research team at the AWI Institute detected extremely high quantities of microplastic particles in the sediment back in 2016.
Previous studies had already shown that the Artic sea ice can contain as much as 12,000 microplastic particles per litre of meltwater. "When this ice reaches the end of its journey and melts in the northern Fram Strait, it most likely releases its microplastic load into the sea, which would explain the high concentration of plastic particles in the surface waters," explains AWI biologist and first author Mine Tekman. Studies of specimens at the bottom of the deep sea in the Fram Strait show a contamination of up to 13,000 microplastic particles per kilogram of sediment. The large quantity of particles and the various types of plastic found in the sediment confirm that microplastic is continually accumulating on the sea floor and that the deep sea in this region is a sink for microscopically small plastic particles, according to AWI deep-sea expert and co-author Dr. Melanie Bergmann. Ocean circulation modelling on the routes taken by the microplastic particles to get into the Fram Strait have also shown that a large number of the particles coming to rest on the ocean floor came from distant regions. Some particles travelled up to 650 kilometres, which disproves the notion that microplastic particles sink rapidly and almost vertically to the bottom.
More information: Original publication https://pubs.acs.org/doi/pdf/10.1021/acs.est.9b06981
Title of the study, which was published in the journal Environmental Science & Technology: Mine B. Tekman, Claudia Wekerle, Claudia Lorenz, Sebastian Primpke, Christiane Hasemann, Gunnar Gerdts, and Melanie Bergmann: Tying up Loose Ends of Microplastic Pollution in the Arctic: Distribution from the Sea Surface through the Water Column to Deep-Sea Sediments at the HAUSGARTEN Observatory.
References:
- https://www.awi.de/ (25.3.2020)
- Photo: © AWI