Sediment accumulation and carbon burial in four hadal trench systems
Oguri, Kazumasa (Japan Agency for Marine-Earth Science and Technology. Research Institute for Global Change)
Masqué Barri, Pere (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Zabel, Matthias (University of Bremen. Center for Marine Environmental Sciences)
Stewart, Heather A. (Lyell Centre. British Geological Survey)
MacKinnon, Gillian (Scottish Universities Environmental Research Centre)
Rowden, Ashley A. (Victoria University of Wellington)
Berg, Peter (University of Virginia. Department of Environmental Sciences)
Wenzhöfer, Frank (Max-Planck-Institute for Marine Microbiology)
Glud, Ronnie N. (University of Southern Denmark. Department of Biology)
Universitat Autònoma de Barcelona. Departament de Física

Fecha:	2022
Resumen:	Hadal trenches are considered to act as depocenters for organic material, although pathways for the material transport and deposition rates are poorly constrained. Here we assess focusing, deposition and accumulation of material and organic carbon in four hadal trench systems underlying different surface ocean productivities; the eutrophic Atacama and Kuril-Kamchatka trenches, the mesotrophic Kermadec trench and the oligotrophic Mariana Trench. The study is based on the distributions of naturally occurring 210Pbex, 137Cs and total organic carbon from recovered sediment cores and by applying previously quantified benthic mineralization rates. Periods of steady deposition and discreet mass-wasting deposits were identified from the profiles and the latter were associated with historic recorded seismic events in the respective regions. During periods without mass wasting, the estimated focusing factors along trench axes were elevated, suggesting more or less continuous downslope focusing of material toward the interior of the trenches. The estimated organic carbon deposition rates during these periods exhibited extensive site-specific variability, but were generally similar to values encountered at much shallower settings such as continental slopes and margins. Organic carbon deposition rates during periods of steady deposition were not mirrored by surface ocean productivity, but appeared confounded by local bathymetry. The inclusion of deposition mediated by mass-wasting events enhanced the sediment and organic carbon accumulations for the past ∼150 years by up to a factor of ∼4. Thus, due to intensified downslope material focusing and infrequent mass-wasting events, hadal trenches are important sites for deposition and sequestration of organic carbon in the deep sea.
Ayudas:	European Commission 669947 Ministerio de Economía y Competitividad MDM2015-0552
Nota:	Unidad de excelencia María de Maeztu CEX2019-000940-M
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Focusing factor ; Hadal trench ; Mass accumulation rate ; Mass-wasting event ; Organic carbon deposition rate ; Radionuclides
Publicado en:	Journal of Geophysical Research: Biogeosciences, Vol. 127, Issue 10 (October 2022) , art. e2022JG006814, ISSN 2169-8961

DOI: 10.1029/2022JG006814

23 p, 1.2 MB

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