Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise)
The Southern Ocean (SO) is of global importance to the carbon cycle, and processes such as mesopelagic remineralisation that impact the efficiency of the biological carbon pump in this region need to be better constrained. During this study early austral winter barium excess (Ba xs ) concentrations...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2022
|
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-19-3209-2022 https://doaj.org/article/65f6fb131ed8466c8a4d8812377f060c |
id |
ftdoajarticles:oai:doaj.org/article:65f6fb131ed8466c8a4d8812377f060c |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:65f6fb131ed8466c8a4d8812377f060c 2023-05-15T18:25:43+02:00 Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise) N. R. van Horsten H. Planquette G. Sarthou T. J. Ryan-Keogh N. Lemaitre T. N. Mtshali A. Roychoudhury E. Bucciarelli 2022-07-01T00:00:00Z https://doi.org/10.5194/bg-19-3209-2022 https://doaj.org/article/65f6fb131ed8466c8a4d8812377f060c EN eng Copernicus Publications https://bg.copernicus.org/articles/19/3209/2022/bg-19-3209-2022.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-19-3209-2022 1726-4170 1726-4189 https://doaj.org/article/65f6fb131ed8466c8a4d8812377f060c Biogeosciences, Vol 19, Pp 3209-3224 (2022) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/bg-19-3209-2022 2022-12-30T21:16:01Z The Southern Ocean (SO) is of global importance to the carbon cycle, and processes such as mesopelagic remineralisation that impact the efficiency of the biological carbon pump in this region need to be better constrained. During this study early austral winter barium excess (Ba xs ) concentrations were measured for the first time, along 30 ∘ E in the southern Indian Ocean. Winter Ba xs concentrations of 59 to 684 pmol L −1 were comparable to those observed throughout other seasons. The expected decline of the mesopelagic Ba xs signal to background values during winter was not observed, supporting the hypothesis that this remineralisation proxy likely has a longer timescale than previously reported. A compilation of available SO mesopelagic Ba xs data, including data from this study, shows an accumulation rate of ∼0.9 µ mol m −2 d −1 from September to July that correlates with temporally integrated remotely sensed primary productivity (PP) throughout the SO from data spanning ∼20 years, advocating for a possible annual timescale of this proxy. The percentage of mesopelagic particulate organic carbon (POC) remineralisation as calculated from estimated POC remineralisation fluxes over integrated remotely sensed PP was ∼2 -fold higher south of the polar front (19 ± 15 %, n =39 ) than north of the polar front (10 ± 10 %, n =29 ), revealing the higher surface carbon export efficiency further south. By linking integrated remotely sensed PP to mesopelagic Ba xs stock, we could obtain better estimates of carbon export and remineralisation signals within the SO on annual and basin scales. Article in Journal/Newspaper Southern Ocean Directory of Open Access Journals: DOAJ Articles Southern Ocean Austral Indian Biogeosciences 19 13 3209 3224 |
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. R. van Horsten H. Planquette G. Sarthou T. J. Ryan-Keogh N. Lemaitre T. N. Mtshali A. Roychoudhury E. Bucciarelli Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise) |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
The Southern Ocean (SO) is of global importance to the carbon cycle, and processes such as mesopelagic remineralisation that impact the efficiency of the biological carbon pump in this region need to be better constrained. During this study early austral winter barium excess (Ba xs ) concentrations were measured for the first time, along 30 ∘ E in the southern Indian Ocean. Winter Ba xs concentrations of 59 to 684 pmol L −1 were comparable to those observed throughout other seasons. The expected decline of the mesopelagic Ba xs signal to background values during winter was not observed, supporting the hypothesis that this remineralisation proxy likely has a longer timescale than previously reported. A compilation of available SO mesopelagic Ba xs data, including data from this study, shows an accumulation rate of ∼0.9 µ mol m −2 d −1 from September to July that correlates with temporally integrated remotely sensed primary productivity (PP) throughout the SO from data spanning ∼20 years, advocating for a possible annual timescale of this proxy. The percentage of mesopelagic particulate organic carbon (POC) remineralisation as calculated from estimated POC remineralisation fluxes over integrated remotely sensed PP was ∼2 -fold higher south of the polar front (19 ± 15 %, n =39 ) than north of the polar front (10 ± 10 %, n =29 ), revealing the higher surface carbon export efficiency further south. By linking integrated remotely sensed PP to mesopelagic Ba xs stock, we could obtain better estimates of carbon export and remineralisation signals within the SO on annual and basin scales. |
format |
Article in Journal/Newspaper |
author |
N. R. van Horsten H. Planquette G. Sarthou T. J. Ryan-Keogh N. Lemaitre T. N. Mtshali A. Roychoudhury E. Bucciarelli |
author_facet |
N. R. van Horsten H. Planquette G. Sarthou T. J. Ryan-Keogh N. Lemaitre T. N. Mtshali A. Roychoudhury E. Bucciarelli |
author_sort |
N. R. van Horsten |
title |
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise) |
title_short |
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise) |
title_full |
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise) |
title_fullStr |
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise) |
title_full_unstemmed |
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise) |
title_sort |
early winter barium excess in the southern indian ocean as an annual remineralisation proxy (geotraces gipr07 cruise) |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/bg-19-3209-2022 https://doaj.org/article/65f6fb131ed8466c8a4d8812377f060c |
geographic |
Southern Ocean Austral Indian |
geographic_facet |
Southern Ocean Austral Indian |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Biogeosciences, Vol 19, Pp 3209-3224 (2022) |
op_relation |
https://bg.copernicus.org/articles/19/3209/2022/bg-19-3209-2022.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-19-3209-2022 1726-4170 1726-4189 https://doaj.org/article/65f6fb131ed8466c8a4d8812377f060c |
op_doi |
https://doi.org/10.5194/bg-19-3209-2022 |
container_title |
Biogeosciences |
container_volume |
19 |
container_issue |
13 |
container_start_page |
3209 |
op_container_end_page |
3224 |
_version_ |
1766207336510128128 |