Arctic sea-ice melt triggers nutrient tipping point, threatening the food web
New research shows that rapid Arctic sea-ice loss since 2009 reduced nitrate in the Arctic Ocean via denitrification, limiting the nutrients needed for phytoplankton growth. As more light promotes phytoplankton proliferation, the nitrate pool shrinks, shifting communities toward smaller phytoplankton and weakening energy transfer up the food web, potentially impacting fisheries and carbon sequestration. Recovery of nitrate would be slow even if sea ice rebounds, making nitrate a key driver of future Arctic productivity and climate projections.