RAPID: The Collapsing Ice and Ocean Ecosystem of Milne Fiord, Canada

Cornell University, Ithaca NY

Investigators

Abstract

The Canadian Arctic Archipelago hosts a cluster of ice caps and ice fields that amount to 14% of Earth’s total glaciated area. However, a warming ocean and atmosphere is melting the ice and causing it to flow into the ocean at an increasing rate. This is reducing the volume of Earth’s freshwater reservoir, increasing global sea level, and changing the Arctic marine ecosystem. These changes have global societal and environmental implications. This project will study Milne Fiord, which is the final remaining fjord along the northern coast of Ellesmere Island, Canada, with perennial ice cover – a system that is now breaking up. Milne Fiord hosts a patchwork configuration of sea ice, a marine ice shelf, and a floating glacial ice tongue that covers its sea surface year round. This configuration dams freshwater in the upper water column between floating ice bodies, above their keels, to create a unique epishelf lake ecosystem, where specific organisms reside in a freshwater layer underlain by seawater and separated by a sharp halocline. A calving event in 2020 has triggered rapid changes to this system, which is now breaking up and the epishelf lake is draining. The lake drainage and ice shelf and tongue weakening appears to center around a predominant basal channel in the ice shelf and a set of full-thickness rifts in the ice tongue near the grounding line. A total collapse of this system will result in drainage of the last epishelf lake in Arctic Canada, increased ice-ocean-atmosphere interactions in Milne Fiord, and likely acceleration of the upstream glaciers. This work proposes to test that the long-term increase in atmospheric and oceanic temperatures is increasing basal melting of the Milne ice tongue through increased turbulent ocean heat flux. The project will collect in situ hydrographic profiles and water samples across the fjord. These measurements will be compared with melt rates from phase-sensitive radar to better understand the spatial distribution in ocean forcing and glacial melting in Milne Fiord. These measurements will then be placed into the longer-term context by comparing them to previous hydrographic profiles and mooring timeseries data collected by an ongoing international project between Canadian and US researchers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.