Particle flux in the oceans: Challenging the steady state assumption
Atmospheric carbon dioxide levels are strongly controlled by the depth at which the organic matter that sinks out of the surface ocean is remineralized. This depth is generally estimated from particle flux profiles measured using sediment traps. Inherent in this analysis is a steady state assumption...
Published in: | Global Biogeochemical Cycles |
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ftsouthampton:oai:eprints.soton.ac.uk:404499 2023-07-30T04:05:32+02:00 Particle flux in the oceans: Challenging the steady state assumption Giering, Sarah L.C. Sanders, Richard Martin, Adrian P. Henson, Stephanie A. Riley, Jennifer Marsay, Chris M. Johns, David 2017-01-28 text https://eprints.soton.ac.uk/404499/ https://eprints.soton.ac.uk/404499/1/gbc20503.pdf https://eprints.soton.ac.uk/404499/2/Giering_et_al_2017_Global_Biogeochemical_Cycles.pdf en English eng https://eprints.soton.ac.uk/404499/1/gbc20503.pdf https://eprints.soton.ac.uk/404499/2/Giering_et_al_2017_Global_Biogeochemical_Cycles.pdf Giering, Sarah L.C., Sanders, Richard, Martin, Adrian P., Henson, Stephanie A., Riley, Jennifer, Marsay, Chris M. and Johns, David (2017) Particle flux in the oceans: Challenging the steady state assumption. Global Biogeochemical Cycles, 31 (1), 159-171. (doi:10.1002/2016GB005424 <http://dx.doi.org/10.1002/2016GB005424>). Article PeerReviewed 2017 ftsouthampton https://doi.org/10.1002/2016GB005424 2023-07-09T22:12:47Z Atmospheric carbon dioxide levels are strongly controlled by the depth at which the organic matter that sinks out of the surface ocean is remineralized. This depth is generally estimated from particle flux profiles measured using sediment traps. Inherent in this analysis is a steady state assumption; that export from the surface does not significantly change in the time it takes material to reach the deepest trap. However, recent observations suggest that a significant fraction of material in the mesopelagic zone sinks slowly enough to bring this into doubt. We use data from a study in the North Atlantic during July/August 2009 to challenge the steady state assumption. An increase in biogenic silica flux with depth was observed which we interpret, based on vertical profiles of diatom taxonomy, as representing the remnants of the spring diatom bloom sinking slowly (<40?m d-1). We were able to reproduce this behaviour using a simple model using satellite-derived export rates and literature-derived remineralization rates. We further provide a simple equation to estimate ‘additional’ (or ‘excess’) POC supply to the dark ocean during non-steady state conditions, which is not captured by traditional sediment trap deployments. In seasonal systems, mesopelagic net organic carbon supply could be wrong by as much as 25% when assuming steady state. We conclude that the steady state assumption leads to misinterpretation of particle flux profiles when input fluxes from the upper ocean vary on the order of weeks, such as in temperate and polar regions with strong seasonal cycles in export. Article in Journal/Newspaper North Atlantic University of Southampton: e-Prints Soton Global Biogeochemical Cycles 31 1 159 171 |
institution |
Open Polar |
collection |
University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
Atmospheric carbon dioxide levels are strongly controlled by the depth at which the organic matter that sinks out of the surface ocean is remineralized. This depth is generally estimated from particle flux profiles measured using sediment traps. Inherent in this analysis is a steady state assumption; that export from the surface does not significantly change in the time it takes material to reach the deepest trap. However, recent observations suggest that a significant fraction of material in the mesopelagic zone sinks slowly enough to bring this into doubt. We use data from a study in the North Atlantic during July/August 2009 to challenge the steady state assumption. An increase in biogenic silica flux with depth was observed which we interpret, based on vertical profiles of diatom taxonomy, as representing the remnants of the spring diatom bloom sinking slowly (<40?m d-1). We were able to reproduce this behaviour using a simple model using satellite-derived export rates and literature-derived remineralization rates. We further provide a simple equation to estimate ‘additional’ (or ‘excess’) POC supply to the dark ocean during non-steady state conditions, which is not captured by traditional sediment trap deployments. In seasonal systems, mesopelagic net organic carbon supply could be wrong by as much as 25% when assuming steady state. We conclude that the steady state assumption leads to misinterpretation of particle flux profiles when input fluxes from the upper ocean vary on the order of weeks, such as in temperate and polar regions with strong seasonal cycles in export. |
format |
Article in Journal/Newspaper |
author |
Giering, Sarah L.C. Sanders, Richard Martin, Adrian P. Henson, Stephanie A. Riley, Jennifer Marsay, Chris M. Johns, David |
spellingShingle |
Giering, Sarah L.C. Sanders, Richard Martin, Adrian P. Henson, Stephanie A. Riley, Jennifer Marsay, Chris M. Johns, David Particle flux in the oceans: Challenging the steady state assumption |
author_facet |
Giering, Sarah L.C. Sanders, Richard Martin, Adrian P. Henson, Stephanie A. Riley, Jennifer Marsay, Chris M. Johns, David |
author_sort |
Giering, Sarah L.C. |
title |
Particle flux in the oceans: Challenging the steady state assumption |
title_short |
Particle flux in the oceans: Challenging the steady state assumption |
title_full |
Particle flux in the oceans: Challenging the steady state assumption |
title_fullStr |
Particle flux in the oceans: Challenging the steady state assumption |
title_full_unstemmed |
Particle flux in the oceans: Challenging the steady state assumption |
title_sort |
particle flux in the oceans: challenging the steady state assumption |
publishDate |
2017 |
url |
https://eprints.soton.ac.uk/404499/ https://eprints.soton.ac.uk/404499/1/gbc20503.pdf https://eprints.soton.ac.uk/404499/2/Giering_et_al_2017_Global_Biogeochemical_Cycles.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://eprints.soton.ac.uk/404499/1/gbc20503.pdf https://eprints.soton.ac.uk/404499/2/Giering_et_al_2017_Global_Biogeochemical_Cycles.pdf Giering, Sarah L.C., Sanders, Richard, Martin, Adrian P., Henson, Stephanie A., Riley, Jennifer, Marsay, Chris M. and Johns, David (2017) Particle flux in the oceans: Challenging the steady state assumption. Global Biogeochemical Cycles, 31 (1), 159-171. (doi:10.1002/2016GB005424 <http://dx.doi.org/10.1002/2016GB005424>). |
op_doi |
https://doi.org/10.1002/2016GB005424 |
container_title |
Global Biogeochemical Cycles |
container_volume |
31 |
container_issue |
1 |
container_start_page |
159 |
op_container_end_page |
171 |
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1772817520665821184 |