Observations of diapycnal upwelling within a sloping submarine canyon
Wynne-Cattanach, B.L.; Couto, N.; Drake, H.F.; Ferrari, R.; Le Boyer, A.; Mercier, H.; Messias, M.-J.; Ruan, X.; Spingys, C.P.; van Haren, H.; Voet, G.; Polzin, K.; Naveira Garabato, A.C.; Alford, M.H. (2024). Observations of diapycnal upwelling within a sloping submarine canyon. Nature (Lond.) 630(8018): 884-890. https://dx.doi.org/10.1038/s41586-024-07411-2 In: Nature: International Weekly Journal of Science. Nature Publishing Group: London. ISSN 0028-0836; e-ISSN 1476-4687, more |   |
| Authors | | Top | - Wynne-Cattanach, B.L.
- Couto, N.
- Drake, H.F.
- Ferrari, R.
- Le Boyer, A.
| - Mercier, H.
- Messias, M.-J.
- Ruan, X.
- Spingys, C.P.
- van Haren, H., more
| - Voet, G.
- Polzin, K.
- Naveira Garabato, A.C.
- Alford, M.H.
|
| Abstract | Small-scale turbulent mixing drives the upwelling of deep water masses in the abyssal ocean as part of the global overturning circulation1. However, the processes leading to mixing and the pathways through which this upwelling occurs remain insufficiently understood. Recent observational and theoretical work has suggested that deep-water upwelling may occur along the ocean’s sloping seafloor; however, evidence has, so far, been indirect. Here we show vigorous near-bottom upwelling across isopycnals at a rate of the order of 100 metres per day, coupled with adiabatic exchange of near-boundary and interior fluid. These observations were made using a dye released close to the seafloor within a sloping submarine canyon, and they provide direct evidence of strong, bottom-focused diapycnal upwelling in the deep ocean. This supports previous suggestions that mixing at topographic features, such as canyons, leads to globally significant upwelling. The upwelling rates observed were approximately 10,000 times higher than the global average value required for approximately 30 × 106 m3 s−1 of net upwelling globally. |
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