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Arctic oases: The role of polynyas

This article is part of a series highlighting issues from the Conservation of Arctic Flora and Fauna (CAFF) working group’s landmark Arctic Biodiversity Assessment. This week focuses on polynyas – areas of open water surrounded by sea ice.

Some of the most productive marine ecosystems on Earth are found in the outer Arctic seas and in recurring areas of open water, amid sea ice, called polynyas. Many species of invertebrates, fish, seabirds and marine mammals gather at such sites making polynyas important biological hotspots in the Arctic. For example, the entire world population of spectacled eiders, a large sea duck, winter in temporary fractures in sea ice, called leads, and polynyas south of St. Lawrence Island in the eastern Bering Sea. Large recurrent polynyas provide conditions for a diverse array of birds to remain for the winter, as well as ice-associated species of seals and whales.

In regions of very high tidal currents, such as those produced in narrow inlets, small tidal polynyas remain open throughout the winter, providing refuges when shore-leads, open water areas that occur between the shore and drift ice, close. These tidal polynyas become areas of high biodiversity through the concentration of a wide variety of marine birds, and sometimes whales and seals.

Click here to read more from the “Marine Ecosystems” chapter in the ABA.

Click here to learn more about sea ice associated biodiversity in CAFF’s Life Linked to Ice Report.

For more biodiversity graphics, please visit the Arctic Biodiversity Data Service: