Ellesmere Island in Canada’s Nunavut territory once held a rare natural feature that no longer exists. An epishelf lake formed when an ice shelf blocked a fjord, allowing freshwater from melting ice to pool on top of denser seawater below. The two layers stayed separate, supporting both freshwater and marine life in the same body of water. That lake at Milne Fjord drained away after the ice shelf broke apart in 2020, and researchers say it will not return. ([1])
A Delicate Balance That Once Existed
The setup depended on the ice shelf acting like a dam. Meltwater collected in the fjord and floated because it was lighter than the seawater underneath. This created a stable freshwater layer on top that could reach significant depth while the salt water remained below. Species adapted to each environment lived side by side without mixing freely. Such lakes were once more common along Ellesmere’s northern coast. Estimates from earlier decades placed the number between 10 and 17. Each one formed in a similar way behind ice shelves that extended from the land into the sea. The arrangement offered a glimpse of how polar ecosystems can function when ice remains intact for long periods.
The Break That Ended the Lake
The Milne Ice Shelf calved in 2020, opening a path for the freshwater to flow out to sea. Without the barrier, the layered system collapsed. Scientists who studied the site afterward concluded the lake is unlikely to re-form even if new ice develops, because the underlying conditions have shifted. Meltwater still gathers in depressions on the remaining ice shelf each summer. Those seasonal pools, however, no longer stay trapped behind a solid dam. The change marks the end of Canada’s last known example of this type of lake.
Signals From the Last Ice Area
Ellesmere Island sits inside the region scientists call the Last Ice Area. The name reflects the expectation that sea ice would persist here longer than in other parts of the Arctic as global temperatures rise. The loss at Milne Fjord shows that even this relatively protected zone is experiencing rapid change. Study co-author Derek Mueller noted that events in the Arctic carry consequences far beyond the region itself. The disappearance of the lake adds to a pattern of ice shelves fracturing and retreating along the coast. Earlier in the 20th century, multiple epishelf lakes existed in similar settings. Their steady decline tracks the broader retreat of ice in the area.
Looking Ahead
The loss removes one of the few places where researchers could observe a layered freshwater and marine system in a polar setting. Future monitoring will focus on how the fjord ecosystem adjusts without the ice dam and whether any similar features appear elsewhere. For communities and scientists who track Arctic conditions, the change serves as a concrete reminder that long-standing assumptions about ice stability are being tested. The outcome at Milne Fjord leaves open questions about what other features tied to ice shelves may face next.
