Glacier-fed rivers can consume atmospheric carbon dioxide

According to a new study by biologists from the University of Alberta, glacially fed northern Canadian rivers could consume considerable amounts of carbon dioxide from the atmosphere.

Researchers examined the Lake Hazen watershed in Quttinirpaaq National Park on Ellesmere Island, Nunavut, to study the impact of glacier melt on marine systems. fresh water.

"We observed that carbon dioxide concentrations in rivers were much lower than in the atmosphere, which means that rivers are actively absorbing carbon dioxide from the atmosphere," explained Kyra St. Pierre, who conducted the study as a PhD student under the supervision of Professor Vincent St. Louis.

Researchers attribute the difference in CO2 to a process called chemical weathering, a series of chemical reactions that occur when materials such as rocks, sediments, and soil come into contact with water and gases. # 39; s atmosphere.

"The glacial landscapes are unique in that they have huge expanses of finely crushed sediments created by the glaciers themselves as they move forward and retreat," St. Pierre said. "As these sediments mix with meltwater, which in turn mix with the atmosphere, they can experience a number of potential chemical alteration reactions, some of which consume carbon dioxide. "

But while reducing carbon dioxide levels in the atmosphere may seem like good news, it has an unknown cost of melting glaciers.

"The melting of glaciers in mountainous and polar regions is one of the most striking consequences of global warming, but the significance of this phenomenon is not always clear," St Pierre said.

"Many of the world's rivers, including the Athabasca and Fraser rivers, here in western Canada, come from glaciers. And yet, despite their importance in our daily lives, we know very little about the functioning of fresh water fed by glaciers. "

Future research will examine the frequency of this weathering phenomenon in the world and its differences between different glacier regions. Work in Jasper and Banff National Parks is already underway and it is planned to expand to other glacier-covered areas in Canada and around the world.

The study entitled "Proglacial freshwaters are important and not yet recognized atmospheric CO2 sinks" was published in Proceedings of the National Academy of Sciences.