Rapid coastal deoxygenation due to ocean circulation shift in the northwest Atlantic
Claret, M.; Galbraith, E.D.; Palter, J.B.; Bianchi, D.; Fennel, K.; Gilbert, D.; Dunne, J.P. (2018). Rapid coastal deoxygenation due to ocean circulation shift in the northwest Atlantic. Nat. Clim. Chang. 8(10): 868-872. https://dx.doi.org/10.1038/s41558-018-0263-1
In: Nature Climate Change. Nature Publishing Group: London. ISSN 1758-678X; e-ISSN 1758-6798, more
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| Authors | | Top |
- Claret, M.
- Galbraith, E.D.
- Palter, J.B.
- Bianchi, D.
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- Fennel, K.
- Gilbert, D.
- Dunne, J.P.
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| Abstract |
Global observations show that the ocean lost approximately 2% of its oxygen inventory over the past five decades with important implications for marine ecosystems. The rate of change varies regionally, with northwest Atlantic coastal waters showing a long-term drop that vastly outpaces the global and North Atlantic basin mean deoxygenation rates. However, past work has been unable to differentiate the role of large-scale climate forcing from that of local processes. Here, we use hydrographic evidence to show that a Labrador Current retreat is playing a key role in the deoxygenation on the northwest Atlantic shelf. A high-resolution global coupled climate–biogeochemistry model reproduces the observed decline of saturation oxygen concentrations in the region, driven by a retreat of the equatorward-flowing Labrador Current and an associated shift towards more oxygen-poor subtropical waters on the shelf. The dynamical changes underlying the shift in shelf water properties are correlated with a slowdown in the simulated Atlantic Meridional Overturning Circulation (AMOC). Our results provide strong evidence that a major, centennial-scale change of the Labrador Current is underway, and highlight the potential for ocean dynamics to impact coastal deoxygenation over the coming century. |
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