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

Heijnen, Maarten; Mienis, F.; Gates, Andrew ORCID: https://orcid.org/0000-0002-2798-5044; Bett, Brian ORCID: https://orcid.org/0000-0003-4977-9361; Hall, R. A.; Hunt, James; Kane, I. A.; Pebody, Corinne; Huvenne, Veerle ORCID: https://orcid.org/0000-0001-7135-6360; Soutter, E. L.; Clare, Michael ORCID: https://orcid.org/0000-0003-1448-3878. 2022 Challenging the highstand-dormant paradigm for land-detached submarine canyons. Nature Communications, 13 (1). https://doi.org/10.1038/s41467-022-31114-9

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Official URL: http://dx.doi.org/10.1038/s41467-022-31114-9

Abstract/Summary

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:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1038/s41467-022-31114-9
Programmes:	NOC Programmes > Ocean BioGeosciences
ISSN:	2041-1723
Date made live:	20 Jul 2022 12:47 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/532855

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1038/s41467-022-31114-9

Programmes:

NOC Programmes > Ocean BioGeosciences

ISSN:

2041-1723

Date made live:

20 Jul 2022 12:47 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/532855