Tracing glacial meltwater from the Greenland Ice Sheet to the ocean using gliders

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

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

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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 coloured 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.
Original languageEnglish
Article numbere2021JC017274
Number of pages17
JournalJournal of Geophysical Research: Oceans
Volume126
Issue number8
Early online date12 Jul 2021
DOIs
Publication statusPublished - 1 Aug 2021

Bibliographical note

Funding Information:
Many thanks to the Captain, crew, National Marine Facility technicians and all the scientists aboard RRS Discovery expedition DY081 for their assistance in deploying and retrieving the gliders, and project manager, Daniel Comben, National Oceanography Center Southampton (NOCS). Many thanks to David White, Steve Woodward, and Candice Cameron for their assistance with glider preparation, deployment and piloting. Funding for DY081 was from the European Research Council (ERC Starting Grant 678371 ICY-LAB). JO is funded by NERC DTP studentship NE/L002582/1. Thanks to H. Claustre (CNRS) for curating the Argo float data. NB and SH were supported by a European Research Council Consolidator grant (GOCART, agreement number 724416) to SH. LM was funded by research program VENI (016.Veni.192.150, NWO). Many thanks to the editor and two anonymous reviewers who provided constructive and detailed suggestions for improving the manuscript.

Funding Information:
Many thanks to the Captain, crew, National Marine Facility technicians and all the scientists aboard RRS Discovery expedition DY081 for their assistance in deploying and retrieving the gliders, and project manager, Daniel Comben, National Oceanography Center Southampton (NOCS). Many thanks to David White, Steve Woodward, and Candice Cameron for their assistance with glider preparation, deployment and piloting. Funding for DY081 was from the European Research Council (ERC Starting Grant 678371 ICY‐LAB). JO is funded by NERC DTP studentship NEL0025821. Thanks to H. Claustre (CNRS) for curating the Argo float data. NB and SH were supported by a European Research Council Consolidator grant (GOCART, agreement number 724416) to SH. LM was funded by research program VENI (016.Veni.192.150, NWO). Many thanks to the editor and two anonymous reviewers who provided constructive and detailed suggestions for improving the manuscript.

Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.

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