Researchers have learned that although the groundwater only makes up 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 in summer. This quantity of carbon is on par with what free-flowing rivers in the area release during summer months.

"This study shows that there are humongous amounts of organic carbon and carbon dioxide released via fresh groundwater discharge in summer," said Cansu Demir, who led the research while she was completing her doctoral degree at the UT Jackson School of Geosciences. She is now a postdoctoral research associate at Los Alamos National Laboratory.

The research is published in Geophysical Research Letters.

As the tundra continues to thaw and the flow of submarine groundwater ratchets up, Demir said that the outflow of carbon from shore to sea could effectively make ocean surface waters a carbon source to the atmosphere. The CO₂ released via groundwater could also contribute to ocean acidification.

The study is the first to use direct observations to show that fresh water is being discharged into the submarine environment of the ocean 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, Demir said.