Greater Precipitation and Meltwater Reduce Nutrient Availability in the Arctic Ocean

Nature Geoscience, August 16

In the western and central Arctic Ocean, distinct layers of ocean water – based on their temperature, salt content and depth – are becoming increasingly divided or “stratified.” This is because rising global temperatures cause an increase in precipitation, river discharge, and glacial melt into the Arctic Ocean. This influx of freshwater increases the stratification between layers of Arctic water, slowing the mixing of deeper nutrient-rich waters with the sunlit surface. Reconstructions of Arctic stratification during the end of the last ice age (11,000 years ago) suggest that sustained warming will increase the separation between these Arctic water layers, reducing nutrient availability and thus impacting the foundation of the Arctic food web.