Tracing Glacial Meltwater From the Greenland Ice Sheet to the Ocean Using Gliders

Hendry, Katharine R.; Briggs, Nathan; Henson, Stephanie; Opher, Jacob; Brearley, James Alexander; Meredith, Michael P.; Leng, Melanie J.; Meire, Lorenz

Abstract

The Greenland Ice Sheet (GrIS) is experiencing significant mass loss and freshwater discharge at glacier fronts. The freshwater input from Greenland will impact the physical properties of adjacent coastal seas, including important regions of deep water formation and contribute to global sea level rise. However, the biogeochemical impact of increasing freshwater discharge from the GrIS is less well constrained. Here, we demonstrate the use of bio-optical sensors on ocean gliders to track biogeochemical properties of meltwaters off southwest Greenland. Our results reveal that fresh, coastal waters, with an oxygen isotopic composition characteristic of glacial meltwater, are distinguished by a high optical backscatter and high levels of fluorescing dissolved organic matter (FDOM), representative of the overall colored dissolved organic matter pool. Reconstructions of geostrophic velocities are used to show that these particle and FDOM-enriched coastal waters cross the strong boundary currents into the Labrador Sea. Meltwater input into the Labrador Sea is likely driven by mesoscale processes, such as eddy formation and local bathymetric steering, in addition to wind-driven Ekman transport. Ocean gliders housing bio-optical sensors can provide the high-resolution observations of both dissolved and particulate glacially derived material that are needed to understand meltwater dispersal mechanisms and their sensitivity to future climatic change.

• Journal Article Type: Article
• Acceptance Date: Jul 1, 2021
• Online Publication Date: Jul 12, 2021
• Publication Date: Aug 1, 2021
• Deposit Date: Jul 21, 2021
• Publicly Available Date: Jul 21, 2021
• Journal: Journal of Geophysical Research: Oceans
• Print ISSN: 2169-9291
• Electronic ISSN: 2169-9291
• Publisher: American Geophysical Union (AGU)
• Peer Reviewed: Peer Reviewed
• Volume: 126
• Issue: 8
• Article Number: e2021JC017274
• DOI: https://doi.org/10.1029/2021JC017274
• Keywords: Earth and Planetary Sciences (miscellaneous); Space and Planetary Science; Geochemistry and Petrology; Geophysics; Oceanography
• Public URL: https://nottingham-repository.worktribe.com/output/5788823
• Publisher URL: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JC017274
• Additional Information: An edited version of this paper was published by AGU. Copyright 2021 American Geophysical Union.