Arctic Groundwater Carrying Lots of Carbon

December 13, 2025

A relatively small amount of groundwater trickling through Alaska’s tundra is releasing huge quantities of carbon into the ocean.

Researchers found that although the groundwater makes up only a fraction of the water discharged to the sea, it’s liberating an estimated 230 tons of organic carbon per day along the almost 2,000-kilometer coastline of the Beaufort Sea during the summer. This quantity of carbon is on a par with what free-flowing rivers in the area release during summer months.

The study is the first to use direct observations to show that freshwater is being discharged into the submarine environment where the coast meets the sea. Before this research, the existence of fresh submarine groundwater discharge in this area of the Arctic was thought to be very limited.

The study is also the first to isolate freshwater — which could be made up of rainwater, snow melt, thawed shallow ground ice, and potentially some permafrost thaw — from the total groundwater discharge.