The role of hadal zones in the long-term fate of marine microplastics: Identification of microplastics in the deep sea of the Kuril-Kamchatka Trench, Northwest Pacific (Deep-MiPoll)
Final Report Abstract
The global use of plastic in everyday life is omnipresent. Oceans are affected by this pollution as they are the final destination of plastic, which is transported to the coast via rivers and the wind. In the ocean, plastic not only causes imbalances in various habitats by facilitating the invasion of invasive species, but it can also slowly kill mammals, seabirds, fish, and sea turtles that become entangled in or eat plastic. One of the biggest concerns, however, is the plastic that has been in the oceans for some time and is breaking down into microplastics (MP) due to extreme environmental conditions such as waves, wind, UV light and hydrolysis. MP, defines plastic that is smaller al 500 µm. It can be very dangerous to marine life because they perceive it as food or accidentally swallow it. Unsatisfactory reports of plastic in the most remote and inaccessible places to humans, such as the Arctic and deep sea, suggest that plastic is omnipresent and that this pollution will have long-term consequences. This work is an investigation of plastic and MP pollution in one of the most remote places on earth, the deepest point of our planet, the abyssal and hadal seafloor. The hypothesis is that the trenches could turn into marine debris garbage cans and serve as plastic repositories. Therefore, the aim of this work was to investigate the spatial distribution of MP and anthropogenic wastes in the sediments of the Kuril-Kamchatka Trench (KKT) in the Northwest Pacific Ocean. The results of initial analyses not only revealed the presence of MP and its polymer composition in the trench sediment, but also highlighted inaccuracies in estimating the amount of MP based on a small sample size. Comprehensive analysis of MP sedimentation and its accumulation in trench sediment revealed a heterogeneous distribution of MP along the sediment column and considerable variation, both at the local scale and throughout the trench system. This heterogeneous distribution reflects the particular dynamics in the trench. L-MP contamination (large MP), representing the size range > 300-500 µm, and the presence of macroplastics were examined, that plastic contamination in the trench consisted of items primarily of single-use plastic and materials used in fisheries. Several items with inscriptions still visible in Asian languages suggest that the main source of pollution to the trench is the Kuroshio Expanse, the northward-flowing Western Pacific Current along the Asian coast. Deep-sea pollution must be attributed to a global contribution and underscores the urgency of changing global policies on plastic and waste use, starting with consumer awareness. Considering the totality of the analyses on plastics and MP carried out in the MiPoll project, as well as the considerations based on a literature review, the focus will be on: a) the main points that can help to optimize the representativeness of a sample and/or a sampling plan, and b) the presentation of environmental data that correspond as closely as possible to plastic contamination in marine sediments.
Publications
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(2020): Systematic identification of microplastics in abyssal and hadal sediments of the Kuril Kamchatka trench. Environmental Pollution
Abel, S. M.; Primpke, S.; Int-Veen, I.; Brandt, A.; Gerdts, G.
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(2022): Human footprints at hadal depths: interlayer and intralayer comparison of sediment cores from the Kuril Kamchatka trench. Science of the Total Environment 838
Abel, S.M., Primpke, S., Wu, F., Brandt, A., Gerdt, G.
