Canada’s sole remaining epishelf lake, characterized by freshwater floating above saltwater, has vanished, along with its distinct ecosystem, as confirmed by scientists in a recent study. Jérémie Bonneau, the study’s lead author and an assistant professor at Laval University in Quebec City, expressed sadness over the disappearance of the Milne Fiord epishelf lake on Ellesmere Island in Nunavut, emphasizing that it was the last of its kind in Canada.
The loss of this unique phenomenon underscores the impact of a warming climate on the Arctic region. While the demise of the lake had been previously reported, the newly published study in the journal Scientific Reports elaborates on the event, describing it as an irreversible loss signifying the end of a 4000-year era.
Epishelf lakes form due to the damming effect of ice shelves, such as the Milne Ice Shelf in this case, which prevented freshwater from mixing with seawater, resulting in a distinct freshwater layer floating on top of the denser saltwater. The lake, hidden beneath a layer of ice year-round, had been accumulating freshwater for millennia.
The lake supported two separate ecosystems within its layers, with minimal overlap between the freshwater and saltwater communities. The disappearance of the lake following the collapse of the Milne Ice Shelf in 2020 led to the rapid mixing of freshwater and seawater, causing the demise of organisms adapted to the lake’s unique conditions.
The study details the rapid draining of the freshwater from the fiord after the ice shelf’s collapse, leading to the immediate loss of the lake’s inhabitants. While epishelf lakes no longer exist in Canada, similar features can still be found in Greenland and Antarctica. However, researchers warn that these ecosystems are also at risk due to ongoing environmental changes, highlighting the fragility of our planet’s unique natural wonders.
