Observations of diapycnal upwelling within a sloping submarine canyon

• 成果类型: Article
• 署名作者: Wynne-Cattanach, Bethan L.; Couto, Nicole; Drake, Henri F.; Ferrari, Raffaele; Le Boyer, Arnaud; Mercier, Herle; Messias, Marie-Jose; Ruan, Xiaozhou; Spingys, Carl P.; van Haren, Hans; Voet, Gunnar; Polzin, Kurt; Garabato, Alberto C. Naveira; Alford, Matthew H.
• 署名单位: University of California System; University of California San Diego; Scripps Institution of Oceanography; University of California System; University of California Irvine; Massachusetts Institute of Technology (MIT); Institut de Recherche pour le Developpement (IRD); Ifremer; Universite de Bretagne Occidentale; Centre National de la Recherche Scientifique (CNRS); University of Exeter; Boston University; NERC National Oceanography Centre; Utrecht University; Royal Netherlands Institute for Sea Research (NIOZ); Woods Hole Oceanographic Institution; University of Southampton
• 刊物名称: Nature
• ISSN/ISSBN: 0028-4271
• DOI: 10.1038/s41586-024-07411-2
• 发表日期: 2024-06-27
• 关键词: antarctic bottom water; deep-ocean; rough topography; kaena ridge; turbulent; circulation; DISSIPATION; transport; patterns; tracer

摘要

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 work2-5 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 upwelling3,6-8. The upwelling rates observed were approximately 10,000 times higher than the global average value required for approximately 30 x 106 m3 s-1 of net upwelling globally9. A dye-release experiment within a sloping submarine canyon provides direct evidence that vigorous mixing at topographic features, such as canyons, leads to rapid diapycnal upwelling of deep water.