Photo: Unsplash // Alexander Hafemann
The Arctic Ocean absorbs as much as 180 million metric tons of carbon per year, making it a key carbon sink for the Earth. However, recent scientific findings have shown that warming waters can cause at least one region of the ocean to release more carbon dioxide than it absorbs, according to NASA’s Jet Propulsion Laboratory.
The region in question is the Beaufort Sea and the culprit for this phenomena is runoff from the nearby Mackenzie River in Canada’s northwest territories. The Mackenzie is the continent’s second largest river system. As it flows to its eventual outlet in the Arctic Ocean, it picks up mineral nutrients as well as organic and inorganic matter. The resulting carbon and sediment is eventually drained into the Beaufort Sea, where it releases into the atmosphere in a process called outgassing. However, in recent years, the Mackenzie River and its delta have endured significantly warmer temperatures across all seasons, which leads to accelerated thawing and thus greater runoff into the ocean.
In the study, published earlier this year, scientists used a computer model adapted from a global ocean biogeochemical model called ECCO-Darwin to simulate the Mackenzie’s discharge of fresh water and sediment into the Beaufort Sea from 2000 to 2019. They found that the river discharge triggered so much outgassing that it led to a net release of carbon dioxide. In fact, the output was calculated at 0.13 million metric tons per year, or the equivalent to around the annual emissions of 28,000 gasoline-powered cars.
“With our model, we are trying to explore the real contribution of the coastal peripheries and rivers to the Arctic carbon cycle,” said lead author Clément Bertin, a scientist at Littoral Environnement et Sociétés in France. The findings go a long way to understanding the ways that even small changes in the ocean can have wide-reaching consequences for our environment.
