The magnitude of microplastics (MPs) sinking flux and its temporal variability is crucial to understanding the global fate of MPs in the ocean. MPs have been reported in deep Arctic sediments as well as in the water column; however, the mechanisms driving their vertical transport are still unclear, and little is known about MPs sinking dynamics and export to the seafloor. Within the JPI-Oceans FACTS project, we measured MPs vertical fluxes along the water column in two Arctic glacial fjords (Kongsfjorden and Krossfjorden) located in the Svalbard archipelago. Sinking particles were collected using moored sediment traps over the course of two years. The moorings were located in strategic areas from both a hydrological and depositional point of view, where Atlantic water masses entering the fjords interact with glacial melt water fronts. In Krossfjorden, a single integrated sample was collected at 110 m below sea level, while in Kongsfjorden, a time-series sediment trap with 12 receiving cups was placed at 61 m depth on September 2021. The interval of this trap rotation was set at ~30 days allowing the study of monthly and seasonal variations in MPs deposition rates. MPs were extracted from the samples through multi-enzymatic digestion, catalyzed oxidation and density separation, and analyzed using state-of-the-art FPA-µFTIR-Imaging. These results shed new light on the temporal variability of MPs vertical fluxes in the Arctic region, providing crucial information about the mechanisms behind their export and removal from the sea surface to the seafloor.

Primary Presenter: Giuseppe Suaria, CNR-ISMAR (giuseppesuaria@gmail.com)

Authors:

Giuseppe Suaria, CNR-ISMAR, Lerici, Italy  (giuseppe.suaria@sp.ismar.cnr.it)

Andrea Paluselli, CNR-ISMAR, Lerici, Italy  (andrea.paluselli@sp.ismar.cnr.it)

Alvise Vianello, Aalborg University, Denmark  (avia@build.aau.dk)

Laura Simon Sánchez, Aalborg University, Denmark  (lasisa@build.aau.dk)

Federico Giglio, CNR-ISP, Bologna, Italy  (federico.giglio@bo.ismar.cnr.it)

Patrizia Giordano, CNR-ISP, Bologna, Italy  (patrizia.giordano@cnr.it)

Claudia Lorenz, Aalborg University, Denmark  (clo@build.aau.dk)

Leonardo Langone, CNR-ISP, Bologna, Italy  (leonardo.langone@cnr.it)

Stefano Miserocchi, CNR-ISP, Bologna, Italy  (stefano.miserocchi@cnr.it)

Jes Vollertsen, Aalborg University, Denmark  ()

Stefano Aliani, CNR-ISMAR, Lerici, Italy  (stefano.aliani@sp.ismar.cnr.it)