Longest sediment flows yet measured show how major rivers connect efficiently to deep sea

Talling, Peter J.; Baker, Megan L.; Pope, Ed L.; Ruffell, Sean C.; Silva Jacinto, Ricardo; Heijnen, Maarten S.; Hage, Sophie; Simmons, Stephen; Hasenhündl, Martin; Heerema, Catharina J.; McGee, Claire; Apprioual, Ronan; Ferrant, Anthony; Cartigny, Matthieu J.B.; Parsons, Daniel R.; Clare, Michael A.; Tshimanga, Raphael; Trigg, Mark A.; Cula, Costa A.; Faria, Rui; Gaillot, Arnaud; Bola, Gode; Wallance, Dec; Griffiths, Allan; Nunny, Robert; Urlaub, Morelia; Peirce, Christine; Burnett, Richard; Neasham, Jeffrey; Hilton, Robert J.

Abstract

We document directly for the first time how major river floods connect to the deep-sea, by analysing the longest runout sediment flows (of any type) yet measured in action. These seafloor turbidity currents originated from the Congo River-mouth, with one flow travelling >1,130 km whilst accelerating from 5.2 to 8.0 m/s. In one year, these turbidity currents eroded 1,338-2,675 [>535-1,070] Mt of sediment from one submarine canyon, equivalent to 19-37 [>7-15] % of annual suspended sediment flux from present-day rivers. It was known earthquakes trigger canyon-flushing flows. We show river-floods also generate canyon-flushing flows, primed by rapid sediment-accumulation at the river-mouth, and sometimes triggered by spring tides weeks to months post-flood. This is the first field confirmation that eroding turbidity currents can self-accelerate, thereby travelling much further. These observations explain highly-efficient organic carbon transfer, and have important implications for hazards to seabed cables, or deep-sea impacts of terrestrial climate change.

Citation

Talling, P. J., Baker, M. L., Pope, E. L., Ruffell, S. C., Silva Jacinto, R., Heijnen, M. S., …Hilton, R. J. (2022). Longest sediment flows yet measured show how major rivers connect efficiently to deep sea. Nature communications, 13, Article 4193. https://doi.org/10.1038/s41467-022-31689-3

• Journal Article Type: Article
• Acceptance Date: May 22, 2022
• Online Publication Date: Jul 20, 2022
• Publication Date: Jul 20, 2022
• Deposit Date: May 23, 2022
• Publicly Available Date: Oct 27, 2022
• Journal: Nature communications
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Article Number: 4193
• DOI: https://doi.org/10.1038/s41467-022-31689-3
• Public URL: https://hull-repository.worktribe.com/output/4002571
• Publisher URL: Homepage: https://www.nature.com/ncomms/