Seawater sampling in 2020 for subsurface microplastic analysis in the western Arctic Ocean

The distribution of microplastic in the open ocean of the Arctic Ocean is largely undocumented. Substantial numbers of studies on microplastics have been reported in the Pacific and Atlantic Oceans, yet very few data are available in the polar oceans. In the present study, we conducted microplastic surveys along the cruise track to fill gaps in the Arctic Ocean.Sea subsurface (ca. 7 m depth below sea surface) microplastic samples were collected using a pumped seawater system of the ship throughout the cruise. The pumped unfiltered seawater was continuously filtered through a 333 μm mesh screen and then 100 μm mesh screen at a flow rate about 3–4 L/min, enabling ca. 5,000 L per day. These meshes were collected and replaced every 24 hours, and the collected meshes were wrapped with an aluminum foil and stored in a vacuum sealed aluminum bag at room temperature until analysis.Microplastic samples from the pumped seawater will be subjected to enumeration and identification of plastic types using a microscope and FT-IR. The distribution, density and concentration of microplastic in this study will be compared with the previous reports in the Arctic Ocean.