Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic
The remineralisation of sinking particles by prokaryotic heterotrophic activity is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May–...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/261743 2023-08-20T04:07:50+02:00 Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic Lemaitre, Nolwenn Planquette, Helene Planchon, Frédéric Sarthou, Géraldine Jacquet, Stéphanie García-Ibáñez, Maribel I. Gourain, Arthur Cheize, Marie Monin, Laurence André, Luc Laha, Priya Terryn, Herman Dehairs, Frank 2018 application/application/pdf https://hdl.handle.net/20.500.11850/261743 https://doi.org/10.3929/ethz-b-000261743 en eng Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-15-2289-2018 info:eu-repo/semantics/altIdentifier/wos/000430485900001 http://hdl.handle.net/20.500.11850/261743 doi:10.3929/ethz-b-000261743 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International Biogeosciences, 15 (8) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2018 ftethz https://doi.org/20.500.11850/26174310.3929/ethz-b-00026174310.5194/bg-15-2289-2018 2023-07-30T23:47:39Z The remineralisation of sinking particles by prokaryotic heterotrophic activity is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May–June 2014) using the particulate biogenic barium (excess barium; Baxs) proxy. Important mesopelagic (100–1000 m) Baxs differences were observed along the transect depending on the intensity of past blooms, the phytoplankton community structure, and the physical forcing, including downwelling. The subpolar province was characterized by the highest mesopelagic Baxs content (up to 727 pmol L−1), which was attributed to an intense bloom averaging 6 mg chl a m−3 between January and June 2014 and by an intense 1500 m deep convection in the central Labrador Sea during the winter preceding the sampling. This downwelling could have promoted a deepening of the prokaryotic heterotrophic activity, increasing the Baxs content. In comparison, the temperate province, characterized by the lowest Baxs content (391 pmol L−1), was sampled during the bloom period and phytoplankton appear to be dominated by small and calcifying species, such as coccolithophorids. The Baxs content, related to oxygen consumption, was converted into a remineralisation flux using an updated relationship, proposed for the first time in the North Atlantic. The estimated fluxes were of the same order of magnitude as other fluxes obtained using independent methods (moored sediment traps, incubations) in the North Atlantic. Interestingly, in the subpolar and subtropical provinces, mesopelagic POC remineralisation fluxes (up to 13 and 4.6 mmol C m−2 d−1, respectively) were equalling and occasionally even exceeding upper-ocean POC export fluxes, deduced using the 234Th method. These results highlight the important impact of the mesopelagic remineralisation on the biological carbon pump of the studied area with a near-zero, deep (> 1000 m) carbon sequestration ... Article in Journal/Newspaper Labrador Sea North Atlantic ETH Zürich Research Collection |
institution |
Open Polar |
collection |
ETH Zürich Research Collection |
op_collection_id |
ftethz |
language |
English |
description |
The remineralisation of sinking particles by prokaryotic heterotrophic activity is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May–June 2014) using the particulate biogenic barium (excess barium; Baxs) proxy. Important mesopelagic (100–1000 m) Baxs differences were observed along the transect depending on the intensity of past blooms, the phytoplankton community structure, and the physical forcing, including downwelling. The subpolar province was characterized by the highest mesopelagic Baxs content (up to 727 pmol L−1), which was attributed to an intense bloom averaging 6 mg chl a m−3 between January and June 2014 and by an intense 1500 m deep convection in the central Labrador Sea during the winter preceding the sampling. This downwelling could have promoted a deepening of the prokaryotic heterotrophic activity, increasing the Baxs content. In comparison, the temperate province, characterized by the lowest Baxs content (391 pmol L−1), was sampled during the bloom period and phytoplankton appear to be dominated by small and calcifying species, such as coccolithophorids. The Baxs content, related to oxygen consumption, was converted into a remineralisation flux using an updated relationship, proposed for the first time in the North Atlantic. The estimated fluxes were of the same order of magnitude as other fluxes obtained using independent methods (moored sediment traps, incubations) in the North Atlantic. Interestingly, in the subpolar and subtropical provinces, mesopelagic POC remineralisation fluxes (up to 13 and 4.6 mmol C m−2 d−1, respectively) were equalling and occasionally even exceeding upper-ocean POC export fluxes, deduced using the 234Th method. These results highlight the important impact of the mesopelagic remineralisation on the biological carbon pump of the studied area with a near-zero, deep (> 1000 m) carbon sequestration ... |
format |
Article in Journal/Newspaper |
author |
Lemaitre, Nolwenn Planquette, Helene Planchon, Frédéric Sarthou, Géraldine Jacquet, Stéphanie García-Ibáñez, Maribel I. Gourain, Arthur Cheize, Marie Monin, Laurence André, Luc Laha, Priya Terryn, Herman Dehairs, Frank |
spellingShingle |
Lemaitre, Nolwenn Planquette, Helene Planchon, Frédéric Sarthou, Géraldine Jacquet, Stéphanie García-Ibáñez, Maribel I. Gourain, Arthur Cheize, Marie Monin, Laurence André, Luc Laha, Priya Terryn, Herman Dehairs, Frank Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic |
author_facet |
Lemaitre, Nolwenn Planquette, Helene Planchon, Frédéric Sarthou, Géraldine Jacquet, Stéphanie García-Ibáñez, Maribel I. Gourain, Arthur Cheize, Marie Monin, Laurence André, Luc Laha, Priya Terryn, Herman Dehairs, Frank |
author_sort |
Lemaitre, Nolwenn |
title |
Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic |
title_short |
Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic |
title_full |
Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic |
title_fullStr |
Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic |
title_full_unstemmed |
Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic |
title_sort |
particulate barium tracing of significant mesopelagic carbon remineralisation in the north atlantic |
publisher |
Copernicus |
publishDate |
2018 |
url |
https://hdl.handle.net/20.500.11850/261743 https://doi.org/10.3929/ethz-b-000261743 |
genre |
Labrador Sea North Atlantic |
genre_facet |
Labrador Sea North Atlantic |
op_source |
Biogeosciences, 15 (8) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-15-2289-2018 info:eu-repo/semantics/altIdentifier/wos/000430485900001 http://hdl.handle.net/20.500.11850/261743 doi:10.3929/ethz-b-000261743 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International |
op_doi |
https://doi.org/20.500.11850/26174310.3929/ethz-b-00026174310.5194/bg-15-2289-2018 |
_version_ |
1774719738155368448 |