Canada’s sole remaining epishelf lake, a rare body of freshwater floating on saltwater, has disappeared, along with its distinctive ecosystem, as confirmed by scientists in a recent study. Jérémie Bonneau, an assistant professor at Laval University in Quebec City and the study’s lead author, expressed sadness over the loss of the Milne Fiord epishelf lake on Ellesmere Island in Nunavut, emphasizing that it was the last of its kind in Canada.
Bonneau highlighted that the vanishing of this once common phenomenon serves as a clear indicator of the impact of a warming climate on the Arctic region. While previous reports had documented the lake’s demise, the latest study, recently published in the journal Scientific Reports, provides a detailed account of the events leading to its disappearance, describing the irreversible loss as the end of a 4000-year era and a significant regime shift.
Epishelf lakes, formed when freshwater accumulates on top of denser saltwater due to natural barriers like ice shelves, create unique ecosystems. The Milne Fiord epishelf lake, connected to the ocean by an under-ice channel, had been accumulating freshwater for millennia, with a distinct separation between the freshwater and saltwater communities within its layers.
Researchers studying the lake discovered a diverse array of bacteria, viruses, and phytoplankton in the two distinct layers, with minimal overlap between the ecosystems. The sudden collapse of the Milne Ice Shelf in 2020 led to the lake’s drainage, resulting in the demise of its inhabitants as freshwater mixed with seawater, drastically altering the marine environment in the fiord.
Although epishelf lakes have disappeared from Canada, some still exist in Greenland and Antarctica. However, scientists warn that these unique ecosystems may also be at risk due to ongoing climate changes. This loss underscores the fragility of these remarkable natural systems and the urgent need for conservation efforts to protect our planet’s diverse ecosystems.