Canada has lost its last remaining epishelf lake, a unique ecosystem where freshwater floated on top of saltwater, according to scientists. The disappearance of the Milne Fiord epishelf lake on Ellesmere Island in Nunavut marks the end of a 4000-year era. The lead author, Jérémie Bonneau, expressed sadness over the loss, emphasizing that this phenomenon’s complete vanishing underscores the impact of a warming climate on the Arctic.
The recent study, published in Scientific Reports, delves into the process of how the lake vanished after the collapse of the Milne Ice Shelf. The lake’s formation, with a freshwater layer sitting atop the denser saltwater due to a natural damming effect by the ice shelf, created a unique environment. The lake had been accumulating freshwater for millennia, with a significant depth of around 18 meters in 1983.
The ecosystem within the epishelf lake was distinct, showcasing separate communities of bacteria, viruses, and phytoplankton in the freshwater and saltwater layers. The study revealed species not previously documented in the Arctic, highlighting the lake’s ecological significance. The lake also supported a diverse marine ecosystem below its surface, as observed by researchers using a remotely operated vehicle.
The collapse of the Milne Ice Shelf in 2020 led to the lake’s drainage, causing the freshwater and saltwater to mix, ultimately leading to the demise of the unique organisms residing in the lake. The disappearance of the lake highlights the irreversible impact of environmental changes in the Arctic due to climate warming.
While epishelf lakes no longer exist in Canada, a few still survive in Greenland and Antarctica. Scientists fear that these ecosystems are also at risk, emphasizing the need for conservation efforts to protect such unique natural wonders.
