Sea ice traps large amounts of microplastics and transports them across the Arctic Ocean according to a study in Nature Communications this week. This finding demonstrates that sea ice can act as a temporary sink for microplastics, and confirms that large amounts may be released into the ocean as climate change leads to increased sea ice melting.

Ilka Peeken and colleagues analyse the composition of microplastics (plastics smaller than 5 mm) in ice cores and sea-ice drift trajectories, and use an ice-growth model to identify regions where microplastics become trapped during sea-ice growth. They find that polymer composition varies across ice cores and identify unique compositions for different areas of origin. They also demonstrate that their sea-ice samples originated from the Amerasian and Eurasian Basins, and that most were transported through the Central Arctic via the Transpolar Drift, a major Arctic current.

The authors argue that microplastic distribution in the Central Arctic is more complex than previously considered and that microplastics released from melting sea ice have the potential to be distributed across surface and deeper waters in the Arctic Ocean.