Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing
The Arctic Ocean and adjacent seas are undergoing increased freshwater influx due to enhanced glacial and sea ice melt, precipitation, and runoff. Accurate delineation of these freshwater sources is vital as they critically modulate ocean composition and circulation with widespread and varied impact...
Published in: | Journal of Geophysical Research: Oceans |
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ftmichigantuniv:oai:digitalcommons.mtu.edu:michigantech-p2-1929 2024-09-30T14:22:25+00:00 Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing Kopec, Ben Klein, Eric S. Feldman, Gene C. Pedron, Shawn A. Bailey, Hannah Causey, Douglas Hubbard, Alun Marttila, Hannu Welker, Jeffrey M. 2024-07-01T07:00:00Z https://digitalcommons.mtu.edu/michigantech-p2/930 https://doi.org/10.1029/2023JC020583 unknown Digital Commons @ Michigan Tech https://digitalcommons.mtu.edu/michigantech-p2/930 doi:10.1029/2023JC020583 https://doi.org/10.1029/2023JC020583 Michigan Tech Publications, Part 2 Arctic Ocean climate change freshwater stable isotopes water cycle Great Lakes Research Center Physical Sciences and Mathematics text 2024 ftmichigantuniv https://doi.org/10.1029/2023JC020583 2024-09-10T00:06:46Z The Arctic Ocean and adjacent seas are undergoing increased freshwater influx due to enhanced glacial and sea ice melt, precipitation, and runoff. Accurate delineation of these freshwater sources is vital as they critically modulate ocean composition and circulation with widespread and varied impacts. Despite this, the delineation of freshwater sources using physical oceanographic measurements (e.g., temperature, salinity) alone is challenging and there is a requirement to improve the partitioning of ocean water masses and their mixing relationships. Here, we complement traditional oceanographic measurements with continuous surface seawater isotopic analysis (δ18O and deuterium excess) across a transect extending from coastal Alaska to Baffin Bay and the Labrador Sea conducted from the US Coast Guard Cutter Healy in Autumn 2021. We find that the diverse isotopic signatures of Arctic freshwater sources, coupled with the high freshwater proportion in these marine systems, facilitates detailed fingerprinting and partitioning. We observe the highest freshwater composition in the Beaufort Sea and Amundsen Gulf regions, with heightened freshwater content in eastern Baffin Bay adjacent to West Greenland. We apply isotopic analysis to delineate freshwater sources, revealing that in the Western Arctic freshwater inputs are dominated by meteoric water inputs—specifically the Mackenzie River—with a smaller sea ice meltwater component and in Baffin Bay the primary sources are local precipitation and glacial meltwater discharge. We demonstrate that such freshwater partitioning cannot be achieved using temperature-salinity relationships alone, and highlight the potential of seawater isotopic tracers to assess the roles and importance of these evolving freshwater sources. Text Amundsen Gulf Arctic Arctic Ocean Baffin Bay Baffin Bay Baffin Beaufort Sea Climate change Greenland Labrador Sea Sea ice Alaska Michigan Technological University: Digital Commons @ Michigan Tech Arctic Arctic Ocean Baffin Bay Greenland Journal of Geophysical Research: Oceans 129 7 |
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Michigan Technological University: Digital Commons @ Michigan Tech |
op_collection_id |
ftmichigantuniv |
language |
unknown |
topic |
Arctic Ocean climate change freshwater stable isotopes water cycle Great Lakes Research Center Physical Sciences and Mathematics |
spellingShingle |
Arctic Ocean climate change freshwater stable isotopes water cycle Great Lakes Research Center Physical Sciences and Mathematics Kopec, Ben Klein, Eric S. Feldman, Gene C. Pedron, Shawn A. Bailey, Hannah Causey, Douglas Hubbard, Alun Marttila, Hannu Welker, Jeffrey M. Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing |
topic_facet |
Arctic Ocean climate change freshwater stable isotopes water cycle Great Lakes Research Center Physical Sciences and Mathematics |
description |
The Arctic Ocean and adjacent seas are undergoing increased freshwater influx due to enhanced glacial and sea ice melt, precipitation, and runoff. Accurate delineation of these freshwater sources is vital as they critically modulate ocean composition and circulation with widespread and varied impacts. Despite this, the delineation of freshwater sources using physical oceanographic measurements (e.g., temperature, salinity) alone is challenging and there is a requirement to improve the partitioning of ocean water masses and their mixing relationships. Here, we complement traditional oceanographic measurements with continuous surface seawater isotopic analysis (δ18O and deuterium excess) across a transect extending from coastal Alaska to Baffin Bay and the Labrador Sea conducted from the US Coast Guard Cutter Healy in Autumn 2021. We find that the diverse isotopic signatures of Arctic freshwater sources, coupled with the high freshwater proportion in these marine systems, facilitates detailed fingerprinting and partitioning. We observe the highest freshwater composition in the Beaufort Sea and Amundsen Gulf regions, with heightened freshwater content in eastern Baffin Bay adjacent to West Greenland. We apply isotopic analysis to delineate freshwater sources, revealing that in the Western Arctic freshwater inputs are dominated by meteoric water inputs—specifically the Mackenzie River—with a smaller sea ice meltwater component and in Baffin Bay the primary sources are local precipitation and glacial meltwater discharge. We demonstrate that such freshwater partitioning cannot be achieved using temperature-salinity relationships alone, and highlight the potential of seawater isotopic tracers to assess the roles and importance of these evolving freshwater sources. |
format |
Text |
author |
Kopec, Ben Klein, Eric S. Feldman, Gene C. Pedron, Shawn A. Bailey, Hannah Causey, Douglas Hubbard, Alun Marttila, Hannu Welker, Jeffrey M. |
author_facet |
Kopec, Ben Klein, Eric S. Feldman, Gene C. Pedron, Shawn A. Bailey, Hannah Causey, Douglas Hubbard, Alun Marttila, Hannu Welker, Jeffrey M. |
author_sort |
Kopec, Ben |
title |
Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing |
title_short |
Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing |
title_full |
Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing |
title_fullStr |
Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing |
title_full_unstemmed |
Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing |
title_sort |
arctic freshwater sources and ocean mixing relationships revealed with seawater isotopic tracing |
publisher |
Digital Commons @ Michigan Tech |
publishDate |
2024 |
url |
https://digitalcommons.mtu.edu/michigantech-p2/930 https://doi.org/10.1029/2023JC020583 |
geographic |
Arctic Arctic Ocean Baffin Bay Greenland |
geographic_facet |
Arctic Arctic Ocean Baffin Bay Greenland |
genre |
Amundsen Gulf Arctic Arctic Ocean Baffin Bay Baffin Bay Baffin Beaufort Sea Climate change Greenland Labrador Sea Sea ice Alaska |
genre_facet |
Amundsen Gulf Arctic Arctic Ocean Baffin Bay Baffin Bay Baffin Beaufort Sea Climate change Greenland Labrador Sea Sea ice Alaska |
op_source |
Michigan Tech Publications, Part 2 |
op_relation |
https://digitalcommons.mtu.edu/michigantech-p2/930 doi:10.1029/2023JC020583 https://doi.org/10.1029/2023JC020583 |
op_doi |
https://doi.org/10.1029/2023JC020583 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
129 |
container_issue |
7 |
_version_ |
1811634071149740032 |