How Greenland’s glacial channels influence oceanic circulation

Fountain: Geophysics Research Magazine: Oceans

He Southpiece of Atlantic (AMOC) circulation It serves as the Atlantic Ocean conveyor belt, transporting warm water to the north to the Arctic Circle and returning cold and dense water back to the tropics. The areas close to the coast in Greenland are critical sites in AMOC, which influence heat redistribution and nutrients worldwide.

The continental platform along the coast of Greenland is marked by deep grooves called glacial channels that extend from the mouths of glacially carved fjords to the open ocean. Research in Antarctica suggests that glacial channels improve the mix of cold and warm waters, but few observations have been collected to determine if the same is true for the Greenland channels.

Aboard R/V. Neil Armstrong At the end of the summer of 2022, as part of a Back in the North Atlantic Subpolar program cruise funded by the National Science Foundation, Nelson et al. explored how channels influence oceanic circulation Around Greenland. They collected data in southwest Greenland in the Narsaq channel, which has 30 kilometers wide in its mouth and reaches 600 meters at its deepest point, approximately 4 times deeper than the average of the surrounding continental platform. The collection of measurements along multiple ship tracks allowed researchers to compare water mass properties inside and outside the channel, describe flows inside and around it and estimate the mixture of water with different temperatures and nutrient concentrations.

The results showed that the Narsaq channel provides a route for warm and salty Atlantic water to end the continental platform and mix with cold and fresh polar waters. Consequently, the waters on the channel are cooler, richer in oxygen, less rich in nutrients and, sometimes, colder than the high seas waters. These changes in water conditions can slightly limit the merger of glacial ice in the adjacent fjord. In addition, the channel creates a subsurface circulation that probably exports the modified water of the channel, which can increase stratification and decrease Deep water formation outside the continental platform.

The study offers new ideas about the little studied glacial authors of Greenland and their role in the modulation of the climate system, say the authors. However, they point out that more work is needed to establish the cumulative effects of the channels on global oceanic circulation. (Geophysics Research Magazine: Oceans, https://doi.org/10.1029/2024JC0222462025)

—Aaron Sidder, scientific writer

Citation: Sidder, A. (2025), how Greenland’s glacial channels influence oceanic circulation, EOS, 106, https://doi.org/10.1029/2025o250205. Posted on May 29, 2025.

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