In a recent study, researchers have confirmed that Canada’s last remaining epishelf lake, which comprised freshwater floating on saltwater, has disappeared along with its unique ecosystem. Jérémie Bonneau, an assistant professor at Laval University in Quebec City and the lead author of the study, expressed sadness over the loss of the Milne Fiord epishelf lake on Ellesmere Island in Nunavut, highlighting its significance as the final known occurrence of its kind in Canada.
The complete vanishing of this once prevalent phenomenon serves as a stark indicator of the Arctic’s transformation due to a warming climate. While the lake’s demise had been previously documented, the new study, recently published in the journal Scientific Reports, provides detailed insights into the event and emphasizes that its irreversible loss signifies a significant shift and marks the conclusion of a 4000-year era.
Epishelf lakes form as a result of glaciers damming freshwater from flowing into the sea, allowing it to accumulate on top of the Arctic Ocean’s saltwater due to the freshwater’s lower density. The Milne Fiord epishelf lake, covered by a year-round ice layer, had been accumulating freshwater for over four millennia. The lake’s unique ecosystem, consisting of separate freshwater and saltwater communities living in close proximity, showcased a distinct biological diversity rarely found elsewhere.
Following the collapse of the Milne Ice Shelf off the coast of Ellesmere Island in 2020, the lake was no longer contained, resulting in the drainage of its freshwater contents within two months. The sudden mixing of freshwater with seawater led to the immediate demise of the lake’s inhabitants. With epishelf lakes now extinct in Canada, similar ecosystems in Greenland and Antarctica face an uncertain future, underscoring the irreversible impact of climate change on these remarkable natural phenomena.