Yukon River Affected By Permafrost Loss With Global Effects

Climate change is causing not only permafrost loss in Alaska but also changing the freshwater chemistry and hydrology of Alaska's Yukon River Basin. These changes could have a profound impact on global climate, as revealed in a study published in Geophysical Research Letters.

Led by Ryan Toohey of the Department of the Interior's Alaska Climate Science Center, the study presents the cascading effects of such significant chemical changes on freshwater, oceanic, and high-latitude ecosystems, the carbon cycle, and the rural communities that rely on the Yukon River.

A depository of millennia of frozen water, minerals, nutrients and contaminants, permafrost could be found below the Yukon River Basin. Above the permafrost is the 'active layer' of soil that freezes and thaws each year, providing flora and fauna with minerals and nutrients. With the thawing of the permafrost, the chemical composition of both surface water and groundwater are altered.

"As the climate gets warmer, the thawing permafrost not only enables the release of more greenhouse gases to the atmosphere, but our study shows that it also allows much more mineral-laden and nutrient-rich water to be transported to rivers, groundwater and eventually the Arctic Ocean," explained Toohey. "Changes to the chemistry of the Arctic Ocean could lead to changes in currents and weather patterns worldwide."

Closely related to Toohey's research is the study by University of Alberta scientist Suzanne Tank who recorded similar changes on the Mackenzie River, a major Arctic river in Canada. Toohey observed that "these trends strongly suggest that permafrost loss is leading to massive changes in hydrology within the arctic and boreal forest that may have consequences for the carbon cycle, fish and wildlife habitat and other ecosystem services."

Upon analyzing more than 30 years of data, Toohey's research reveals how climate change is already affecting the aquatic ecosystems of the Yukon River. These changes could ultimately cause changes in the Arctic Ocean by eventually transforming the way that high-latitude, Northern Hemisphere ecosystems function.