High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th 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 th...
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2018
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ftdoajarticles:oai:doaj.org/article:364701637e6647a1bc13423632f6e46c 2023-05-15T17:30:09+02:00 High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th fluxes N. Lemaitre F. Planchon H. Planquette F. Dehairs D. Fonseca-Batista A. Roukaerts F. Deman Y. Tang C. Mariez G. Sarthou 2018-11-01T00:00:00Z https://doi.org/10.5194/bg-15-6417-2018 https://doaj.org/article/364701637e6647a1bc13423632f6e46c EN eng Copernicus Publications https://www.biogeosciences.net/15/6417/2018/bg-15-6417-2018.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-15-6417-2018 1726-4170 1726-4189 https://doaj.org/article/364701637e6647a1bc13423632f6e46c Biogeosciences, Vol 15, Pp 6417-6437 (2018) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2018 ftdoajarticles https://doi.org/10.5194/bg-15-6417-2018 2022-12-31T03:18:38Z 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 µm) 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. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Irminger Basin ENVELOPE(-36.000,-36.000,61.000,61.000) Biogeosciences 15 21 6417 6437 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 N. Lemaitre F. Planchon H. Planquette F. Dehairs D. Fonseca-Batista A. Roukaerts F. Deman Y. Tang C. Mariez G. Sarthou High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th fluxes |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
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 µm) 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 |
Article in Journal/Newspaper |
author |
N. Lemaitre F. Planchon H. Planquette F. Dehairs D. Fonseca-Batista A. Roukaerts F. Deman Y. Tang C. Mariez G. Sarthou |
author_facet |
N. Lemaitre F. Planchon H. Planquette F. Dehairs D. Fonseca-Batista A. Roukaerts F. Deman Y. Tang C. Mariez G. Sarthou |
author_sort |
N. Lemaitre |
title |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th fluxes |
title_short |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th fluxes |
title_full |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th fluxes |
title_fullStr |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th fluxes |
title_full_unstemmed |
High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234 Th fluxes |
title_sort |
high variability of particulate organic carbon export along the north atlantic geotraces section ga01 as deduced from 234 th fluxes |
publisher |
Copernicus Publications |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-15-6417-2018 https://doaj.org/article/364701637e6647a1bc13423632f6e46c |
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 |
Biogeosciences, Vol 15, Pp 6417-6437 (2018) |
op_relation |
https://www.biogeosciences.net/15/6417/2018/bg-15-6417-2018.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-15-6417-2018 1726-4170 1726-4189 https://doaj.org/article/364701637e6647a1bc13423632f6e46c |
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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1766125978316177408 |