Challenging the highstand-dormant paradigm for land-detached submarine canyons

Heijnen, Maarten, Mienis, Furu, Gates, Andrew, Bett, Brian, Hall, Rob, Hunt, James, Kane, Ian, Pebody, Corrine, Huvenne, Veerle, Soutter, Euan and Clare, Michael (2022) Challenging the highstand-dormant paradigm for land-detached submarine canyons. Nature Communications, 13. ISSN 2041-1723

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Abstract

Sediment, nutrients, organic carbon and pollutants are funnelled down submarine canyons from continental shelves by sediment-laden flows called turbidity currents, which dominate particulate transfer to the deep sea. Post-glacial sea-level rise disconnected more than three quarters of the > 9000 submarine canyons worldwide from their former river or long-shore drift sediment inputs. Existing models therefore assume that land-detached submarine canyons are dormant in the present-day; however, monitoring has focused on land-attached canyons and this paradigm remains untested. Here we present the most detailed field measurements yet of turbidity currents within a land-detached submarine canyon, documenting a remarkably similar frequency (6 yr− 1) and speed (up to 5–8 ms− 1) to those in large land-attached submarine canyons. Major triggers such as storms or earthquakes are not required; instead, seasonal variations in cross-shelf sediment transport explain temporal-clustering of flows, and why the storm season is surprisingly absent of turbidity currents. As > 1000 other canyons have a similar configuration, we propose that contemporary deep-sea particulate transport via such land detached canyons may have been dramatically under-estimated.

Item Type: Article
Additional Information: Acknowledgements: M.S.H., A.G., B.J.B., J.H., C.P., V.A.I.H., and M.A.C. acknowledge funding from Natural Environment Research Council (NERC) National Capability Programme (NE/R015953/1) “Climate Linked Atlantic Sector Science”. F.M. is supported by the Innovational Research Incentives Scheme of the Netherlands Organisation for Scientific Research (NWO-VIDI Grant no. 0.16.161.360). We thank the Captain and crew of RRS Discovery on Cruises DY103 and DY116, Nick Rundle, Paul Provost and Billy Platt for their efforts in preparing, deploying and recovering the M1 mooring. We thank the Captain and crew of RV Pelagia, as well as the NIOZ technicians, for their essential assistance during the deployment and recovery of the M2 mooring. These efforts are particularly noteworthy due to the logistical challenges of mooring recovery during the early phases of the COVID-19 pandemic. Ship time in relation to the M2 mooring was provided by the Royal Netherlands Institute for Sea Research. We thank the staff of the British Ocean Sediment Core Research Facility for assistance with analysis of sediment trap samples.
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: LivePure Connector
Date Deposited: 24 May 2022 15:00
Last Modified: 19 Jun 2022 06:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/85093
DOI: 10.21203/rs.3.rs-1431819/v1

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