High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes
In this study we report particulate organic carbon (POC) export fluxes for different biogeochemical basins in the North Atlantic as part of the GEOTRACES GA01 expedition (GEOVIDE, May–June 2014). Surface POC export fluxes were deduced by combining export fluxes of total Thorium-234 ( 234 Th ) with t...
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ftcopernicus:oai:publications.copernicus.org:bg67909 2023-05-15T17:30:07+02:00 High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes Lemaitre, Nolwenn Planchon, Frédéric Planquette, Hélène Dehairs, Frank Fonseca-Batista, Debany Roukaerts, Arnout Deman, Florian Tang, Yi Mariez, Clarisse Sarthou, Géraldine 2019-01-08 application/pdf https://doi.org/10.5194/bg-15-6417-2018 https://www.biogeosciences.net/15/6417/2018/ eng eng doi:10.5194/bg-15-6417-2018 https://www.biogeosciences.net/15/6417/2018/ eISSN: 1726-4189 Text 2019 ftcopernicus https://doi.org/10.5194/bg-15-6417-2018 2019-12-24T09:49:44Z In this study we report particulate organic carbon (POC) export fluxes for different biogeochemical basins in the North Atlantic as part of the GEOTRACES GA01 expedition (GEOVIDE, May–June 2014). Surface POC export fluxes were deduced by combining export fluxes of total Thorium-234 ( 234 Th ) with the ratio of POC to 234 Th of sinking particles at the depth of export. Particles were collected in two size classes ( >53 and 1–53 µ m) using in situ pumps and the large size fraction was considered representative of sinking material. Surface POC export fluxes revealed latitudinal variations between provinces, ranging from 1.4 mmol m −2 d −1 in the Irminger basin, where the bloom was close to its maximum, to 12 mmol m −2 d −1 near the Iberian Margin, where the bloom had already declined. In addition to the state of progress of the bloom, variations of the POC export fluxes were also related to the phytoplankton size and community structure. In line with previous studies, the presence of coccolithophorids and diatoms appeared to enhance the POC export flux, while the dominance of picophytoplankton cells, such as cyanobacteria, resulted in lower fluxes. The ratio of POC export to primary production (PP) strongly varied regionally and was generally low ( ≤14 %), except at two stations located near the Iberian Margin (35 %) and within the Labrador basin (38 %), which were characterized by unusual low in situ PP. We thus conclude that during the GEOVIDE cruise, the North Atlantic was not as efficient in exporting carbon from the surface, as reported earlier by others. Finally, we also estimated the POC export at 100 m below the surface export depth to investigate the POC transfer efficiencies. This parameter was also highly variable amongst regions, with the highest transfer efficiency at sites where coccolithophorids dominated. Text North Atlantic Copernicus Publications: E-Journals Irminger Basin ENVELOPE(-36.000,-36.000,61.000,61.000) Biogeosciences 15 21 6417 6437 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
In this study we report particulate organic carbon (POC) export fluxes for different biogeochemical basins in the North Atlantic as part of the GEOTRACES GA01 expedition (GEOVIDE, May–June 2014). Surface POC export fluxes were deduced by combining export fluxes of total Thorium-234 ( 234 Th ) with the ratio of POC to 234 Th of sinking particles at the depth of export. Particles were collected in two size classes ( >53 and 1–53 µ m) using in situ pumps and the large size fraction was considered representative of sinking material. Surface POC export fluxes revealed latitudinal variations between provinces, ranging from 1.4 mmol m −2 d −1 in the Irminger basin, where the bloom was close to its maximum, to 12 mmol m −2 d −1 near the Iberian Margin, where the bloom had already declined. In addition to the state of progress of the bloom, variations of the POC export fluxes were also related to the phytoplankton size and community structure. In line with previous studies, the presence of coccolithophorids and diatoms appeared to enhance the POC export flux, while the dominance of picophytoplankton cells, such as cyanobacteria, resulted in lower fluxes. The ratio of POC export to primary production (PP) strongly varied regionally and was generally low ( ≤14 %), except at two stations located near the Iberian Margin (35 %) and within the Labrador basin (38 %), which were characterized by unusual low in situ PP. We thus conclude that during the GEOVIDE cruise, the North Atlantic was not as efficient in exporting carbon from the surface, as reported earlier by others. Finally, we also estimated the POC export at 100 m below the surface export depth to investigate the POC transfer efficiencies. This parameter was also highly variable amongst regions, with the highest transfer efficiency at sites where coccolithophorids dominated. |
format |
Text |
author |
Lemaitre, Nolwenn Planchon, Frédéric Planquette, Hélène Dehairs, Frank Fonseca-Batista, Debany Roukaerts, Arnout Deman, Florian Tang, Yi Mariez, Clarisse Sarthou, Géraldine |
spellingShingle |
Lemaitre, Nolwenn Planchon, Frédéric Planquette, Hélène Dehairs, Frank Fonseca-Batista, Debany Roukaerts, Arnout Deman, Florian Tang, Yi Mariez, Clarisse Sarthou, Géraldine High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes |
author_facet |
Lemaitre, Nolwenn Planchon, Frédéric Planquette, Hélène Dehairs, Frank Fonseca-Batista, Debany Roukaerts, Arnout Deman, Florian Tang, Yi Mariez, Clarisse Sarthou, Géraldine |
author_sort |
Lemaitre, Nolwenn |
title |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes |
title_short |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes |
title_full |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes |
title_fullStr |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes |
title_full_unstemmed |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes |
title_sort |
high variability of particulate organic carbon export along the north atlantic geotraces section ga01 as deduced from 234th fluxes |
publishDate |
2019 |
url |
https://doi.org/10.5194/bg-15-6417-2018 https://www.biogeosciences.net/15/6417/2018/ |
long_lat |
ENVELOPE(-36.000,-36.000,61.000,61.000) |
geographic |
Irminger Basin |
geographic_facet |
Irminger Basin |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-15-6417-2018 https://www.biogeosciences.net/15/6417/2018/ |
op_doi |
https://doi.org/10.5194/bg-15-6417-2018 |
container_title |
Biogeosciences |
container_volume |
15 |
container_issue |
21 |
container_start_page |
6417 |
op_container_end_page |
6437 |
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1766125911983259648 |