Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation
18 months embargo minus one day to account for leap year. Water-column data from seven cruises in 2007–2008 reveal pronounced temporal and spatial variations in the distribution of dissolved iron (DFe, <0.4 μm) over the upper 1000 m of the Sargasso Sea near Bermuda, in the western subtropical Nor...
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Language: | English |
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Elsevier BV
2020
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Online Access: | http://hdl.handle.net/10026.1/15361 https://doi.org/10.1016/j.marchem.2019.103748 |
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ftunivplympearl:oai:pearl.plymouth.ac.uk:10026.1/15361 2024-06-09T07:48:12+00:00 Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation Sedwick, PN Bowie, AR Church, TM Cullen, JT Johnson, RJ Lohan, MC Marsay, CM McGillicuddy, DJ Sohst, BM Tagliabue, A Ussher, SJ 2020-02-20 103748-103748 application/pdf image/png http://hdl.handle.net/10026.1/15361 https://doi.org/10.1016/j.marchem.2019.103748 en eng Elsevier BV ISSN:0304-4203 ISSN:1872-7581 E-ISSN:1872-7581 0304-4203 1872-7581 103748 http://hdl.handle.net/10026.1/15361 doi:10.1016/j.marchem.2019.103748 2021-7-2 Not known Dissolved iron Seasonal variability Physicochemical speciation Sargasso Sea journal-article Article 2020 ftunivplympearl https://doi.org/10.1016/j.marchem.2019.103748 2024-05-14T23:44:04Z 18 months embargo minus one day to account for leap year. Water-column data from seven cruises in 2007–2008 reveal pronounced temporal and spatial variations in the distribution of dissolved iron (DFe, <0.4 μm) over the upper 1000 m of the Sargasso Sea near Bermuda, in the western subtropical North Atlantic Ocean. In near-surface waters, DFe exhibits a clear seasonal cycle, increasing from ~0.1–0.3 nM in spring to ~0.4–1.0 nM in summer-early fall. The observed seasonal ranges appear to reflect the extent of winter convective mixing and of summer dust deposition, both of which are closely tied to atmospheric circulation processes. Surface DFe concentrations also show significant (~two-fold) submesoscale lateral variations during summer, perhaps as a result of lateral inhomogeneities in wet deposition and wind-driven mixing. The summer vertical profiles reveal pronounced DFe minima and sometimes deeper maxima in the lower euphotic zone, which likely reflect biological uptake and shallow remineralization, and eddy-driven lateral gradients in these processes. Significant variability is also seen in the mesopelagic zone, with a DFe concentration range of ~0.4–0.7 nM at 1000 m depth, which may reflect mesoscale isopycnal displacements and/or lateral advection of iron-rich waters in the lower thermocline. Physicochemical iron speciation measurements indicate that the major fraction of DFe that accumulates in surface waters of the Sargasso Sea during summer is colloidal-sized Fe(III), which appears to be complexed by strong, iron-binding organic ligands. Concentrations of soluble iron (sFe, <0.02 μm) were considerably lower than DFe in the upper euphotic zone during summer, except over the subsurface DFe minima, where sFe accounts for ~50–100% of the DFe pool. Labile Fe(II), on average, accounted for around 20% of DFe, with maximum concentrations of around 0.1 nM in near-surface waters and in the lower thermocline. The seasonal-scale DFe changes that we have documented near Bermuda are of the same magnitude as ... Article in Journal/Newspaper North Atlantic PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) Marine Chemistry 219 103748 |
institution |
Open Polar |
collection |
PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) |
op_collection_id |
ftunivplympearl |
language |
English |
topic |
Dissolved iron Seasonal variability Physicochemical speciation Sargasso Sea |
spellingShingle |
Dissolved iron Seasonal variability Physicochemical speciation Sargasso Sea Sedwick, PN Bowie, AR Church, TM Cullen, JT Johnson, RJ Lohan, MC Marsay, CM McGillicuddy, DJ Sohst, BM Tagliabue, A Ussher, SJ Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation |
topic_facet |
Dissolved iron Seasonal variability Physicochemical speciation Sargasso Sea |
description |
18 months embargo minus one day to account for leap year. Water-column data from seven cruises in 2007–2008 reveal pronounced temporal and spatial variations in the distribution of dissolved iron (DFe, <0.4 μm) over the upper 1000 m of the Sargasso Sea near Bermuda, in the western subtropical North Atlantic Ocean. In near-surface waters, DFe exhibits a clear seasonal cycle, increasing from ~0.1–0.3 nM in spring to ~0.4–1.0 nM in summer-early fall. The observed seasonal ranges appear to reflect the extent of winter convective mixing and of summer dust deposition, both of which are closely tied to atmospheric circulation processes. Surface DFe concentrations also show significant (~two-fold) submesoscale lateral variations during summer, perhaps as a result of lateral inhomogeneities in wet deposition and wind-driven mixing. The summer vertical profiles reveal pronounced DFe minima and sometimes deeper maxima in the lower euphotic zone, which likely reflect biological uptake and shallow remineralization, and eddy-driven lateral gradients in these processes. Significant variability is also seen in the mesopelagic zone, with a DFe concentration range of ~0.4–0.7 nM at 1000 m depth, which may reflect mesoscale isopycnal displacements and/or lateral advection of iron-rich waters in the lower thermocline. Physicochemical iron speciation measurements indicate that the major fraction of DFe that accumulates in surface waters of the Sargasso Sea during summer is colloidal-sized Fe(III), which appears to be complexed by strong, iron-binding organic ligands. Concentrations of soluble iron (sFe, <0.02 μm) were considerably lower than DFe in the upper euphotic zone during summer, except over the subsurface DFe minima, where sFe accounts for ~50–100% of the DFe pool. Labile Fe(II), on average, accounted for around 20% of DFe, with maximum concentrations of around 0.1 nM in near-surface waters and in the lower thermocline. The seasonal-scale DFe changes that we have documented near Bermuda are of the same magnitude as ... |
format |
Article in Journal/Newspaper |
author |
Sedwick, PN Bowie, AR Church, TM Cullen, JT Johnson, RJ Lohan, MC Marsay, CM McGillicuddy, DJ Sohst, BM Tagliabue, A Ussher, SJ |
author_facet |
Sedwick, PN Bowie, AR Church, TM Cullen, JT Johnson, RJ Lohan, MC Marsay, CM McGillicuddy, DJ Sohst, BM Tagliabue, A Ussher, SJ |
author_sort |
Sedwick, PN |
title |
Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation |
title_short |
Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation |
title_full |
Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation |
title_fullStr |
Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation |
title_full_unstemmed |
Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation |
title_sort |
dissolved iron in the bermuda region of the subtropical north atlantic ocean: seasonal dynamics, mesoscale variability, and physicochemical speciation |
publisher |
Elsevier BV |
publishDate |
2020 |
url |
http://hdl.handle.net/10026.1/15361 https://doi.org/10.1016/j.marchem.2019.103748 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
ISSN:0304-4203 ISSN:1872-7581 E-ISSN:1872-7581 0304-4203 1872-7581 103748 http://hdl.handle.net/10026.1/15361 doi:10.1016/j.marchem.2019.103748 |
op_rights |
2021-7-2 Not known |
op_doi |
https://doi.org/10.1016/j.marchem.2019.103748 |
container_title |
Marine Chemistry |
container_volume |
219 |
container_start_page |
103748 |
_version_ |
1801379801719635968 |