Colored dissolved organic matter (CDOM) alters the seasonal physics and biogeochemistry of the Arctic Mackenzie River plume
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bg-22-6607-2025.pdf
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Published version
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7.51 MB
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Author(s)
Bertin, Clément
Le Fouest, Vincent
Carroll, Dustin
Dutkiewicz, Stephanie
Menemenlis, Dimitris
Matsuoka, Atsushi
Manizza, Manfredi
Miller, Charles E
Date Issued
November 7, 2025
Journal
Biogeosciences
Publisher
Copernicus GmbH
Citation
Bertin, C., Le Fouest, V., Carroll, D., Dutkiewicz, S., Menemenlis, D., Matsuoka, A., Manizza, M., and Miller, C. E.: Colored dissolved organic matter (CDOM) alters the seasonal physics and biogeochemistry of the Arctic Mackenzie River plume, Biogeosciences, 22, 6607–6629.
Version
Final published version
Abstract
Arctic warming affects land-to-ocean fluxes of organic matter through increased permafrost thaw, coastal erosion or river discharge, with significant impacts on coastal ecosystems and air-sea CO2 fluxes. In this study, we modify a regional version of the Estimating the Circulation and Climate of the Ocean model coupled to the Darwin ocean biogeochemistry module (ECCO-Darwin) to simulate Mackenzie River export of colored dissolved organic matter (CDOM) and its effect on light attenuation, marine carbon cycling, and water-column heating from UV-A to visible light absorption. We find that CDOM light attenuation triggers both a two-week delay in the seasonal phytoplankton bloom and an increase in sea-surface temperature (SST) by 1.7 °C. While the change in phytoplankton phenology has limited effect on air-sea CO2 fluxes, the local increase in SST due to terrestrial organic matter input switches the coastal zone from an annual sink of atmospheric CO2 to a source (7.35 Gg C yr−1). Our work suggests that the projected increase in terrestrial CDOM has strong implications for phytoplankton phenology and coastal air-sea carbon exchange in the Arctic.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.5194/bg-22-6607-2025
