Spatial Distribution of Microplastics in the Water Column of the coastal Norwegian Sea

• Main Author: Reding, Lina
• Format: Thesis
• Language: unknown
• Published: 2022
• Subjects: Arctic; Norwegian Sea
• Online Access: https://epic.awi.de/id/eprint/57323/; https://hdl.handle.net/10013/epic.a82bfd4e-848b-406f-a7df-0f371e348a75

Despite the mounting awareness of the ubiquity of global plastic pollution, annual production rates of synthetic polymers are increasing exponentially. As this global environmental problem evolves, microplastic research, focusing on plastics of the size < 5 mm, has received growing attention in recent years. The pervasive infiltration of microplastics (MP) in all aquatic environmental compartments is now evident even in the most remote regions including the Arctic. While researchers have reported some of the world's highest MP concentrations in the Arctic marine environment, potential pollutant sources and pathways into this region are poorly understood. The present study therefore investigates the spatial distribution of MP particles (> 11 μm) in the coastal Norwegian Sea to provide comprehensible data on concentrations, polymer composition, and size classes. As part of a sampling campaign, water column samples were taken at 15 stations along the Norwegian Coastal Current (NCC) which acts as an important connector between the more densely populated lower latitudes and the Arctic. Using in situ high-volume filtration two samples of different depths and water layers were collected at each station. Sample purification was performed using an oxidative digestion followed by a density separation to remove all organic and inorganic material present. Isolated MP was subsequently identified and quantified using state-of-the-art focal plane array (FPA) based FTIR imaging technology with automated data analysis. MP particles were identified in a total of 28 out of 30 samples, with concentrations ranging from 4.33 items m-3 to 48.33 items m-3 in the upper water layer and 1.66 items m-3 to 2764 items m-3 in the lower water layer. Overall 13 different polymer types were identified, with polyoxymethylene (38 %) being the most abundant polymer in the upper water layer and polyethylene, rubber type 3, polypropylene and nitrile rubber (all ~16 %) in the lower water layer. A trend towards small MP particles was evident, ...