Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect
We report here the results of total mercury (HgT) determinations along the 2014 G eotraces Geovide cruise (GA01 transect) in the North Atlantic Ocean (NA) from Lisbon (Portugal) to the coast of Labrador (Canada). HgT concentrations in unfiltered samples (HgT UNF ) were log-normally distributed and r...
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2018
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Online Access: | https://doi.org/10.5194/bg-15-2309-2018 https://www.biogeosciences.net/15/2309/2018/ |
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ftcopernicus:oai:publications.copernicus.org:bg62978 2023-05-15T16:28:56+02:00 Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect Cossa, Daniel Heimbürger, Lars-Eric Pérez, Fiz F. García-Ibáñez, Maribel I. Sonke, Jeroen E. Planquette, Hélène Lherminier, Pascale Boutorh, Julia Cheize, Marie Menzel Barraqueta, Jan Lukas Shelley, Rachel Sarthou, Géraldine 2018-09-27 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/bg-15-2309-2018 https://www.biogeosciences.net/15/2309/2018/ eng eng info:eu-repo/grantAgreement/EC/FP7/265113 doi:10.5194/bg-15-2309-2018 https://www.biogeosciences.net/15/2309/2018/ info:eu-repo/semantics/openAccess eISSN: 1726-4189 info:eu-repo/semantics/Text 2018 ftcopernicus https://doi.org/10.5194/bg-15-2309-2018 2019-12-24T09:50:28Z We report here the results of total mercury (HgT) determinations along the 2014 G eotraces Geovide cruise (GA01 transect) in the North Atlantic Ocean (NA) from Lisbon (Portugal) to the coast of Labrador (Canada). HgT concentrations in unfiltered samples (HgT UNF ) were log-normally distributed and ranged between 0.16 and 1.54 pmol L −1 , with a geometric mean of 0.51 pmol L −1 for the 535 samples analysed. The dissolved fraction (< 0.45 µm) of HgT (HgT F ), determined on 141 samples, averaged 78 % of the HgT UNF for the entire data set, 84 % for open seawaters (below 100 m) and 91 % if the Labrador Sea data are excluded, where the primary production was high (with a winter convection down to 1400 m). HgT UNF concentrations increased eastwards and with depth from Greenland to Europe and from subsurface to bottom waters. The HgT UNF concentrations were similarly low in the subpolar gyre waters ( ∼ 0.45 pmol L −1 ), whereas they exceeded 0.60 pmol L −1 in the subtropical gyre waters. The HgT UNF distribution mirrored that of dissolved oxygen concentration, with highest concentration levels associated with oxygen-depleted zones. The relationship between HgT F and the apparent oxygen utilization confirms the nutrient-like behaviour of Hg in the NA. An extended optimum multiparameter analysis allowed us to characterize HgT UNF concentrations in the different source water types (SWTs) present along the transect. The distribution pattern of HgT UNF , modelled by the mixing of SWTs, show Hg enrichment in Mediterranean waters and North East Atlantic Deep Water and low concentrations in young waters formed in the subpolar gyre and Nordic seas. The change in anthropogenic Hg concentrations in the Labrador Sea Water during its eastward journey suggests a continuous decrease in Hg content in this water mass over the last decades. Calculation of the water transport driven by the Atlantic Meridional Overturning Circulation across the Portugal–Greenland transect indicates northward Hg transport within the upper limb and southward Hg transport within the lower limb, with resulting net northward transport of about 97.2 kmol yr −1 . Other/Unknown Material Greenland Labrador Sea Nordic Seas North Atlantic North East Atlantic Copernicus Publications: E-Journals Canada Greenland Biogeosciences 15 8 2309 2323 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
We report here the results of total mercury (HgT) determinations along the 2014 G eotraces Geovide cruise (GA01 transect) in the North Atlantic Ocean (NA) from Lisbon (Portugal) to the coast of Labrador (Canada). HgT concentrations in unfiltered samples (HgT UNF ) were log-normally distributed and ranged between 0.16 and 1.54 pmol L −1 , with a geometric mean of 0.51 pmol L −1 for the 535 samples analysed. The dissolved fraction (< 0.45 µm) of HgT (HgT F ), determined on 141 samples, averaged 78 % of the HgT UNF for the entire data set, 84 % for open seawaters (below 100 m) and 91 % if the Labrador Sea data are excluded, where the primary production was high (with a winter convection down to 1400 m). HgT UNF concentrations increased eastwards and with depth from Greenland to Europe and from subsurface to bottom waters. The HgT UNF concentrations were similarly low in the subpolar gyre waters ( ∼ 0.45 pmol L −1 ), whereas they exceeded 0.60 pmol L −1 in the subtropical gyre waters. The HgT UNF distribution mirrored that of dissolved oxygen concentration, with highest concentration levels associated with oxygen-depleted zones. The relationship between HgT F and the apparent oxygen utilization confirms the nutrient-like behaviour of Hg in the NA. An extended optimum multiparameter analysis allowed us to characterize HgT UNF concentrations in the different source water types (SWTs) present along the transect. The distribution pattern of HgT UNF , modelled by the mixing of SWTs, show Hg enrichment in Mediterranean waters and North East Atlantic Deep Water and low concentrations in young waters formed in the subpolar gyre and Nordic seas. The change in anthropogenic Hg concentrations in the Labrador Sea Water during its eastward journey suggests a continuous decrease in Hg content in this water mass over the last decades. Calculation of the water transport driven by the Atlantic Meridional Overturning Circulation across the Portugal–Greenland transect indicates northward Hg transport within the upper limb and southward Hg transport within the lower limb, with resulting net northward transport of about 97.2 kmol yr −1 . |
format |
Other/Unknown Material |
author |
Cossa, Daniel Heimbürger, Lars-Eric Pérez, Fiz F. García-Ibáñez, Maribel I. Sonke, Jeroen E. Planquette, Hélène Lherminier, Pascale Boutorh, Julia Cheize, Marie Menzel Barraqueta, Jan Lukas Shelley, Rachel Sarthou, Géraldine |
spellingShingle |
Cossa, Daniel Heimbürger, Lars-Eric Pérez, Fiz F. García-Ibáñez, Maribel I. Sonke, Jeroen E. Planquette, Hélène Lherminier, Pascale Boutorh, Julia Cheize, Marie Menzel Barraqueta, Jan Lukas Shelley, Rachel Sarthou, Géraldine Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect |
author_facet |
Cossa, Daniel Heimbürger, Lars-Eric Pérez, Fiz F. García-Ibáñez, Maribel I. Sonke, Jeroen E. Planquette, Hélène Lherminier, Pascale Boutorh, Julia Cheize, Marie Menzel Barraqueta, Jan Lukas Shelley, Rachel Sarthou, Géraldine |
author_sort |
Cossa, Daniel |
title |
Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect |
title_short |
Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect |
title_full |
Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect |
title_fullStr |
Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect |
title_full_unstemmed |
Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect |
title_sort |
mercury distribution and transport in the north atlantic ocean along the geotraces-ga01 transect |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-15-2309-2018 https://www.biogeosciences.net/15/2309/2018/ |
geographic |
Canada Greenland |
geographic_facet |
Canada Greenland |
genre |
Greenland Labrador Sea Nordic Seas North Atlantic North East Atlantic |
genre_facet |
Greenland Labrador Sea Nordic Seas North Atlantic North East Atlantic |
op_source |
eISSN: 1726-4189 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/265113 doi:10.5194/bg-15-2309-2018 https://www.biogeosciences.net/15/2309/2018/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-15-2309-2018 |
container_title |
Biogeosciences |
container_volume |
15 |
container_issue |
8 |
container_start_page |
2309 |
op_container_end_page |
2323 |
_version_ |
1766018620417114112 |