In July 2020, the Milne Ice Sheet on Ellesmere Island shattered, causing a rare freshwater lake to drain into the Arctic Ocean. this collapse, which erased 40% of the shelf's surface in only 48 hours, effectively ended the last major Canadian Arctic epishelf lake.
The 40% loss of the Milne Ice Sheet in 48 hours
In July 2020, the Milne Ice Sheet on northern Ellesmere Island experienced a catastrophic structural failure. According to the report, the collapse erased more than 40% of the ice shelf's total area in a mere two-day window.
This sudden disintegration left the remaining ice shelf at approximately 80 square kilometers, which represents only one-third of its original extent. The lake had formed through the slow accumulation of glacial meltwater behind the ice shelf over many centuries,creating a stable freshwater reservoir that was suddenly lost when the ice dam failed.
A dual-layered habitat of zooplankton and sea anemones
Epishelf lakes create a unique ecological corridor where freshwater sits atop denser saltwater, separated only by a thin boundary of density. This stratification supports a specialized biological community: freshwater zooplanton and phytoplankton thrive near the surface,while marine invertebrates such as brittle stars, sea anemones, and scallops occupy the dark, underlying meltwater channels. The disappearance of this rare corridor highlights the extreme vulnerability of sea-ice-dependent life forms that rely on these specific density boundaries to survive.
Monitoring since 2011 by Hamilton and Bonneau
Researchers from the University of Alberta and Université Laval have been tracking these environmental shifts for over a decade. As reported in the journal Scientific Reports, oceanographer Andrew Hamilton and professor Jérémie Bonneau utilized satellite imagery and oceanographic tools to monior the ice since 2011.
The study highlights that while the ice had been thinning for years, the 2020 breakup was the final catalyst for the lake's disappearance. Hamilton noted that his 2017 observation of an outflow channel beneath the ice shelf revealed a robust marine community living in total darkness, a sight that underscored the fragility of these ecosystems before they were lost.
Will Antarctic deep-water warming trigger similar collapses?
While the study provides a clear timeline of the Milne Fiord collapse, several questions remain regarding the broader global impact.. The report notes that warming Antarctic deep ocean waters are currently melting South Pole ice shelves, yet it remains unverified if this will lead to the same type of epishelf lake drainage seen in the Canadian Arctic. Additionally, while the researchers present the permanent loss of these systems as a certainty under current climate trajectories, the report primarily focuses on the Milne Fiord event, leaving the specific temperature thresholds required to safeguard other polar habitats as a matter of scientific inference rather than direct observation.
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