Sea Ice Loss Triggers Major Shift in Arctic Ocean Ecosystems from Lower Nitrogen Levels

Nature Communications Earth and Environment, 28 May 2026

Rapid sea ice loss is driving a fundamental shift in the Arctic Ocean, from a system limited by sunlight to one limited by nitrogen, a nutrient essential for marine life. Using a 25-year record (1998-2023) from the Fram Strait between Greenland and Svalbard, researchers found that nitrate concentrations declined sharply beginning around 2009, shortly after Arctic sea ice underwent major losses. As sea ice retreats, larger areas of open water support greater phytoplankton growth, increasing the consumption and removal of nitrogen from Arctic shelf seas. The study finds that this mechanism has doubled nitrogen losses in some regions, particularly the Chukchi and East Siberian seas, while changes in ocean circulation have spread nitrogen-poor waters across the Arctic. As a result, Arctic ecosystems are becoming reorganized, with declining nitrogen availability favoring smaller plankton species and altering the foundation of the marine food web. The findings indicate that continued sea ice loss could have long-lasting consequences for Arctic ocean productivity and ecosystem functioning.

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