Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms
Lithogenic particles, such as desert dust, have been postulated to influence particulate organic carbon (POC) export to the deep ocean by acting as mineral ballasts. However, an accurate understanding and quantification of the POC–dust association that occurs within the upper ocean is required in or...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-02-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/1007/2014/bg-11-1007-2014.pdf |
| _version_ | 1819232257200619520 |
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| author | M. Bressac C. Guieu D. Doxaran F. Bourrin K. Desboeufs N. Leblond C. Ridame |
| author_facet | M. Bressac C. Guieu D. Doxaran F. Bourrin K. Desboeufs N. Leblond C. Ridame |
| author_sort | M. Bressac |
| collection | DOAJ |
| description | Lithogenic particles, such as desert dust, have been postulated to influence
particulate organic carbon (POC) export to the deep ocean by acting as
mineral ballasts. However, an accurate understanding and quantification of
the POC–dust association that occurs within the upper ocean is required in
order to refine the "ballast hypothesis". In the framework of the DUNE (a
DUst experiment in a low-Nutrient, low-chlorophyll Ecosystem) project, two
artificial seedings were performed seven days apart within large mesocosms.
A suite of optical and biogeochemical measurements were used to quantify
surface POC export following simulated dust events within a low-nutrient,
low-chlorophyll ecosystem. The two successive seedings led to a 2.3–6.7-fold
higher POC flux than the POC flux observed in controlled
mesocosms. A simple linear regression analysis revealed that the lithogenic
fluxes explained more than 85% of the variance in POC fluxes. On the
scale of a dust-deposition event, we estimated that 42–50% of POC fluxes
were strictly associated with lithogenic particles (through aggregation and
most probably sorption processes). Lithogenic ballasting also likely
impacted the remaining POC fraction which resulted from the fertilization
effect. The observations support the "ballast hypothesis" and provide a
quantitative estimation of the surface POC export abiotically triggered by
dust deposition. In this work, we demonstrate that the strength of such a
"lithogenic carbon pump" depends on the biogeochemical conditions of the
water column at the time of deposition. Based on these observations, we
suggest that this lithogenic carbon pump could represent a major
component of the biological pump in oceanic areas subjected to intense
atmospheric forcing. |
| first_indexed | 2024-12-23T11:57:59Z |
| format | Article |
| id | doaj.art-9a7e4eab5dc244c08e129b2dcf069fe1 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-23T11:57:59Z |
| publishDate | 2014-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-9a7e4eab5dc244c08e129b2dcf069fe12022-12-21T17:48:02ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-02-011141007102010.5194/bg-11-1007-2014Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosmsM. Bressac0C. Guieu1D. Doxaran2F. Bourrin3K. Desboeufs4N. Leblond5C. Ridame6ACRI-ST, BP 234, 06904 Sophia-Antipolis, FranceCNRS-INSU, Université Pierre et Marie Curie-Paris 6, UMR7093, Laboratoire d'Océanographie de Villefranche/Mer, Observatoire Océanologique, 06230 Villefranche-sur-Mer, FranceCNRS-INSU, Université Pierre et Marie Curie-Paris 6, UMR7093, Laboratoire d'Océanographie de Villefranche/Mer, Observatoire Océanologique, 06230 Villefranche-sur-Mer, FranceUniversité de Perpignan Via Domitia, CEFREM, CNRS-UPVD, UMR5110, 52 avenue Paul Alduy, 66860 Perpignan, FranceUniversité Paris Diderot, Sorbonne Paris Cité, Université Paris Est Créteil, UMR CNRS 7583, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), 61 av. Gal de Gaulle, 94010 C FranceObservatoire Océanologique de Villefranche/Mer, CNRS, Université Pierre et Marie Curie-Paris 6, 06230 Villefranche-sur-Mer, FranceCNRS-INSU-IRD, Université Pierre et Marie Curie, UMR7159, LOCEAN: Laboratoire d'Océanographie et du Climat: Expérimentation et Approches Numériques, 4 Place Jussieu – 75252 Paris Cedex 05, FranceLithogenic particles, such as desert dust, have been postulated to influence particulate organic carbon (POC) export to the deep ocean by acting as mineral ballasts. However, an accurate understanding and quantification of the POC–dust association that occurs within the upper ocean is required in order to refine the "ballast hypothesis". In the framework of the DUNE (a DUst experiment in a low-Nutrient, low-chlorophyll Ecosystem) project, two artificial seedings were performed seven days apart within large mesocosms. A suite of optical and biogeochemical measurements were used to quantify surface POC export following simulated dust events within a low-nutrient, low-chlorophyll ecosystem. The two successive seedings led to a 2.3–6.7-fold higher POC flux than the POC flux observed in controlled mesocosms. A simple linear regression analysis revealed that the lithogenic fluxes explained more than 85% of the variance in POC fluxes. On the scale of a dust-deposition event, we estimated that 42–50% of POC fluxes were strictly associated with lithogenic particles (through aggregation and most probably sorption processes). Lithogenic ballasting also likely impacted the remaining POC fraction which resulted from the fertilization effect. The observations support the "ballast hypothesis" and provide a quantitative estimation of the surface POC export abiotically triggered by dust deposition. In this work, we demonstrate that the strength of such a "lithogenic carbon pump" depends on the biogeochemical conditions of the water column at the time of deposition. Based on these observations, we suggest that this lithogenic carbon pump could represent a major component of the biological pump in oceanic areas subjected to intense atmospheric forcing.http://www.biogeosciences.net/11/1007/2014/bg-11-1007-2014.pdf |
| spellingShingle | M. Bressac C. Guieu D. Doxaran F. Bourrin K. Desboeufs N. Leblond C. Ridame Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms Biogeosciences |
| title | Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms |
| title_full | Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms |
| title_fullStr | Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms |
| title_full_unstemmed | Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms |
| title_short | Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms |
| title_sort | quantification of the lithogenic carbon pump following a simulated dust deposition event in large mesocosms |
| url | http://www.biogeosciences.net/11/1007/2014/bg-11-1007-2014.pdf |
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